Ease of Leak-Down Test During Change of Valve Seals

I recently described a problem with a used engine (not remanufactured)
that was installed in my 97 tercel. Some fumes were entering the car
when driving, even with the fan on recirculate (but more noticable
when set to ventilate). Sometimes smelling like deisle fumes (burnt
oil), somtimes like burnt rubber or burnt sugar, sometimes
chemical-like, sometimes like dusty air, Most of the time, it is
caustic enough to aggravate the eyes and lungs/throat.

My mechanic will change the valve seals and do a pressure test of the
air heating system. Considering what he is doing, would it be simple
to do a leak-down test? I read about the concept after a friend
pointed it out, but I'm not sure if it would be easy to do in practice
if one is going change the valve seals and pressure test the cooling
system. It /seems/ straightforward, since the shop air is fed through
the spark-plug port. I guess the engine doesn't need to be taken apart
too much to do this?

Tercel Owner

On Wed, 09 Mar 2005 23:47:44 -0500, Tercel Owner <Toyota@Tercel.com>
wrote:
[color=blue]
>I recently described a problem with a used engine (not remanufactured)
>that was installed in my 97 tercel. Some fumes were entering the car
>when driving, even with the fan on recirculate (but more noticable
>when set to ventilate). Sometimes smelling like deisle fumes (burnt
>oil), somtimes like burnt rubber or burnt sugar, sometimes
>chemical-like, sometimes like dusty air, Most of the time, it is
>caustic enough to aggravate the eyes and lungs/throat.
>
>My mechanic will change the valve seals and do a pressure test of the
>air heating system. Considering what he is doing, would it be simple
>to do a leak-down test? I read about the concept after a friend
>pointed it out, but I'm not sure if it would be easy to do in practice
>if one is going change the valve seals and pressure test the cooling
>system. It /seems/ straightforward, since the shop air is fed through
>the spark-plug port. I guess the engine doesn't need to be taken apart
>too much to do this?
>[/color]

it seems you need to be looking for something on the outside of the
engine, possibly leaking onto the exhaust manifold or something like
crankcase vent dumping into the engine comparment. I don't know why the
mechanic is changing the valve seals, does the engine burn a lot of oil?

"Tercel Owner" <Toyota@Tercel.com> wrote in message
news:422FD16F.34E4E34F@Tercel.com...[color=blue]
>I recently described a problem with a used engine (not remanufactured)
> that was installed in my 97 tercel. Some fumes were entering the car
> when driving, even with the fan on recirculate (but more noticable
> when set to ventilate). Sometimes smelling like deisle fumes (burnt
> oil), somtimes like burnt rubber or burnt sugar, sometimes
> chemical-like, sometimes like dusty air, Most of the time, it is
> caustic enough to aggravate the eyes and lungs/throat.
>
> My mechanic will change the valve seals and do a pressure test of the
> air heating system. Considering what he is doing, would it be simple
> to do a leak-down test? I read about the concept after a friend
> pointed it out, but I'm not sure if it would be easy to do in practice
> if one is going change the valve seals and pressure test the cooling
> system. It /seems/ straightforward, since the shop air is fed through
> the spark-plug port. I guess the engine doesn't need to be taken apart
> too much to do this?
>
> Tercel Owner
>[/color]
When you say "pressure test of the air heating system" I assume that you
mean pressure test the cooling system.

Pressure testing the cooling system is easy to do if you have the proper kit
and adapters. Basically, you attach a pump and gauge to the radiator neck
in place of the regular radiator cap. There is also a tool to check the
integrity of the radiator cap itself.

A cylinder leak-down test is slightly more involved but not that difficult
either if you have the proper tools. Basically, you remove a spark plug and
install a pressure gauge in the spark plug port and crank the engine over.
Then you remove the gauge, squirt some oil in, and repeat to see if the
readings change drastically. A change might indicate a piston ring problem.
If the readings are equally low wet or dry, then a valve not seating
properly is probably the culprit. If you're burning oil and the rings are
good, then valve stem seals are probably the culprit.

The engine does not need to be removed from the car or taken apart to do a
cooling system or cylinder compression test.
--
Ray O
correct the return address punctuation to reply

JeB wrote:
[color=blue]
> On Wed, 09 Mar 2005 23:47:44 -0500, Tercel Owner <Toyota@Tercel.com>
> wrote:
>[color=green]
> >I recently described a problem with a used engine (not remanufactured)
> >that was installed in my 97 tercel. Some fumes were entering the car
> >when driving, even with the fan on recirculate (but more noticable
> >when set to ventilate). Sometimes smelling like deisle fumes (burnt
> >oil), somtimes like burnt rubber or burnt sugar, sometimes
> >chemical-like, sometimes like dusty air, Most of the time, it is
> >caustic enough to aggravate the eyes and lungs/throat.
> >
> >My mechanic will change the valve seals and do a pressure test of the
> >air heating system. Considering what he is doing, would it be simple
> >to do a leak-down test? I read about the concept after a friend
> >pointed it out, but I'm not sure if it would be easy to do in practice
> >if one is going change the valve seals and pressure test the cooling
> >system. It /seems/ straightforward, since the shop air is fed through
> >the spark-plug port. I guess the engine doesn't need to be taken apart
> >too much to do this?
> >[/color]
>
> it seems you need to be looking for something on the outside of the
> engine, possibly leaking onto the exhaust manifold or something like
> crankcase vent dumping into the engine comparment. I don't know why the
> mechanic is changing the valve seals, does the engine burn a lot of oil?[/color]

Yes, big time. It is possible that there is a outside leak of oil onto
a hot piece of the exhaust systemIt is also possible for that to be
unrelated to the burning of oil.

Tercel Owner

JeB wrote:
[color=blue]
> On Wed, 09 Mar 2005 23:47:44 -0500, Tercel Owner <Toyota@Tercel.com>
> wrote:
>[color=green]
> >I recently described a problem with a used engine (not remanufactured)
> >that was installed in my 97 tercel. Some fumes were entering the car
> >when driving, even with the fan on recirculate (but more noticable
> >when set to ventilate). Sometimes smelling like deisle fumes (burnt
> >oil), somtimes like burnt rubber or burnt sugar, sometimes
> >chemical-like, sometimes like dusty air, Most of the time, it is
> >caustic enough to aggravate the eyes and lungs/throat.
> >
> >My mechanic will change the valve seals and do a pressure test of the
> >air heating system. Considering what he is doing, would it be simple
> >to do a leak-down test? I read about the concept after a friend
> >pointed it out, but I'm not sure if it would be easy to do in practice
> >if one is going change the valve seals and pressure test the cooling
> >system. It /seems/ straightforward, since the shop air is fed through
> >the spark-plug port. I guess the engine doesn't need to be taken apart
> >too much to do this?
> >[/color]
>
> it seems you need to be looking for something on the outside of the
> engine, possibly leaking onto the exhaust manifold or something like
> crankcase vent dumping into the engine comparment. I don't know why the
> mechanic is changing the valve seals, does the engine burn a lot of oil?[/color]

Yes, big time. It is possible that there is a outside leak of oil onto
a hot piece of the exhaust system. It is also possible for that to be
unrelated to the burning of oil.

Tercel Owner

Ray O wrote:
[color=blue]
> "Tercel Owner" <Toyota@Tercel.com> wrote in message
> news:422FD16F.34E4E34F@Tercel.com...[color=green]
> >I recently described a problem with a used engine (not remanufactured)
> > that was installed in my 97 tercel. Some fumes were entering the car
> > when driving, even with the fan on recirculate (but more noticable
> > when set to ventilate). Sometimes smelling like deisle fumes (burnt
> > oil), somtimes like burnt rubber or burnt sugar, sometimes
> > chemical-like, sometimes like dusty air, Most of the time, it is
> > caustic enough to aggravate the eyes and lungs/throat.
> >
> > My mechanic will change the valve seals and do a pressure test of the
> > air heating system. Considering what he is doing, would it be simple
> > to do a leak-down test? I read about the concept after a friend
> > pointed it out, but I'm not sure if it would be easy to do in practice
> > if one is going change the valve seals and pressure test the cooling
> > system. It /seems/ straightforward, since the shop air is fed through
> > the spark-plug port. I guess the engine doesn't need to be taken apart
> > too much to do this?[/color]
>
>
> When you say "pressure test of the air heating system" I assume that you
> mean pressure test the cooling system.[/color]

Yes. It was suggested in this group. I always thought of the cooling system
as the pathways running through the engine and the rad, and the air-heating
system as the place where air gets heated before it enters the part of the
car occupied by people. But it's all connected.

[color=blue]
> Pressure testing the cooling system is easy to do if you have the proper kit
> and adapters. Basically, you attach a pump and gauge to the radiator neck
> in place of the regular radiator cap. There is also a tool to check the
> integrity of the radiator cap itself.
>
> A cylinder leak-down test is slightly more involved but not that difficult
> either if you have the proper tools. Basically, you remove a spark plug and
> install a pressure gauge in the spark plug port and crank the engine over.
> Then you remove the gauge, squirt some oil in, and repeat to see if the
> readings change drastically. A change might indicate a piston ring problem.
> If the readings are equally low wet or dry, then a valve not seating
> properly is probably the culprit. If you're burning oil and the rings are
> good, then valve stem seals are probably the culprit.
>
> The engine does not need to be removed from the car or taken apart to do a
> cooling system or cylinder compression test.[/color]

From googling (and from speaking to a friend), a leak-down test differs from
a compression test in that shop air is pumped into the combustion chamber
through the hole for the spark plug. Pressure is measured via a gauge on the
hose that supplies the air. One listens for hissing in the exhaust, and the hole
where the driver tops up with oil. One also looks for bubbling in the coolant.
From my picking people's brains (and googling), the difference with compression
testing is that the latter is less revealing, and the pressure for the latter is from
turning the engine.

It turns out that pressure testing the cooling system and the leak-down test is not
too involved (for a professional mechanic's shop), and it was done. No problems.
The leak-down test gave less than 10% (I'm not sure of what), which is suppose
to be good; 20% is considered acceptable. I'll ask about whether he listened for
hissing or checked for coolant bubbles when I pick up the car. I hope he isn't too
aggravated by my telling him how to do his job. He says that the symptoms don't
really indicate the kind of problem that these tests would track down. In fact, this
same oddity was expressed by the person who told me about the leak-down tests.

Tercel Owner

"Tercel Owner" <Toyota@Tercel.com> wrote in message
news:4230BEBB.E1C1E7CF@Tercel.com...[color=blue]
>
>
> Ray O wrote:
>[color=green]
>> "Tercel Owner" <Toyota@Tercel.com> wrote in message
>> news:422FD16F.34E4E34F@Tercel.com...[color=darkred]
>> >I recently described a problem with a used engine (not remanufactured)
>> > that was installed in my 97 tercel. Some fumes were entering the car
>> > when driving, even with the fan on recirculate (but more noticable
>> > when set to ventilate). Sometimes smelling like deisle fumes (burnt
>> > oil), somtimes like burnt rubber or burnt sugar, sometimes
>> > chemical-like, sometimes like dusty air, Most of the time, it is
>> > caustic enough to aggravate the eyes and lungs/throat.
>> >
>> > My mechanic will change the valve seals and do a pressure test of the
>> > air heating system. Considering what he is doing, would it be simple
>> > to do a leak-down test? I read about the concept after a friend
>> > pointed it out, but I'm not sure if it would be easy to do in practice
>> > if one is going change the valve seals and pressure test the cooling
>> > system. It /seems/ straightforward, since the shop air is fed through
>> > the spark-plug port. I guess the engine doesn't need to be taken apart
>> > too much to do this?[/color]
>>
>>
>> When you say "pressure test of the air heating system" I assume that you
>> mean pressure test the cooling system.[/color]
>
> Yes. It was suggested in this group. I always thought of the cooling
> system
> as the pathways running through the engine and the rad, and the
> air-heating
> system as the place where air gets heated before it enters the part of the
> car occupied by people. But it's all connected.
>[/color]

Yes, the heater is basically a mini-radiator.
[color=blue]
>[color=green]
>> Pressure testing the cooling system is easy to do if you have the proper
>> kit
>> and adapters. Basically, you attach a pump and gauge to the radiator
>> neck
>> in place of the regular radiator cap. There is also a tool to check the
>> integrity of the radiator cap itself.
>>
>> A cylinder leak-down test is slightly more involved but not that
>> difficult
>> either if you have the proper tools. Basically, you remove a spark plug
>> and
>> install a pressure gauge in the spark plug port and crank the engine
>> over.
>> Then you remove the gauge, squirt some oil in, and repeat to see if the
>> readings change drastically. A change might indicate a piston ring
>> problem.
>> If the readings are equally low wet or dry, then a valve not seating
>> properly is probably the culprit. If you're burning oil and the rings
>> are
>> good, then valve stem seals are probably the culprit.
>>
>> The engine does not need to be removed from the car or taken apart to do
>> a
>> cooling system or cylinder compression test.[/color]
>
> From googling (and from speaking to a friend), a leak-down test differs
> from
> a compression test in that shop air is pumped into the combustion chamber
> through the hole for the spark plug. Pressure is measured via a gauge on
> the
> hose that supplies the air. One listens for hissing in the exhaust, and
> the hole
> where the driver tops up with oil. One also looks for bubbling in the
> coolant.
> From my picking people's brains (and googling), the difference with
> compression
> testing is that the latter is less revealing, and the pressure for the
> latter is from
> turning the engine.[/color]

Looking back, I actually described a compression test, not a leak-down test,
as you correctly pointed out.
[color=blue]
>
> It turns out that pressure testing the cooling system and the leak-down
> test is not
> too involved (for a professional mechanic's shop), and it was done. No
> problems.
> The leak-down test gave less than 10% (I'm not sure of what), which is
> suppose
> to be good; 20% is considered acceptable. I'll ask about whether he
> listened for
> hissing or checked for coolant bubbles when I pick up the car.[/color]

If the engine is holding air that tightly, it is not very unlikely that
there is a head gasket leak, which would cause the bubbling in the coolant.

Another sign of a head gasket leak is oil in the coolant or coolant in the
oil. In the case of coolant in the oil, the oil will have a milky
appearance.

I hope he isn't too[color=blue]
> aggravated by my telling him how to do his job. He says that the symptoms
> don't
> really indicate the kind of problem that these tests would track down. In
> fact, this
> same oddity was expressed by the person who told me about the leak-down
> tests.
>
> Tercel Owner
>[/color]
True, which is why I had recommended that you let your technician diagnose
the cause of the odor.
--
Ray O
correct the return address punctuation to reply

Ray O wrote:[color=blue]
> A cylinder leak-down test is slightly more involved but not that
> difficult either if you have the proper tools. Basically, you remove
> a spark plug and install a pressure gauge in the spark plug port and
> crank the engine over. Then you remove the gauge, squirt some oil in,
> and repeat to see if the readings change drastically. A change might
> indicate a piston ring problem. If the readings are equally low wet
> or dry, then a valve not seating properly is probably the culprit. If
> you're burning oil and the rings are good, then valve stem seals
> are probably the culprit.[/color]

RayO... BZZZZZZZZZZZZZZZZZZZZzT

You have described a "compression test." (dry test followed by wet test).

A "Cylinder Leakdown Test" is quite a different procedure.

A pressure gauge with an adjustable pressure regulator is needed. This is a
special tool

The crank shaft is positioned at TDC (starting with #1) and secured so that
it cannot turn. Spark plug is removed. Hose adaptor to pressure gauge
installed. Pressure gauge is calibrated using the pressure regulator to the
available shop air pressure line. Gauge is connected to the adaptor hose.
Cylinder is pressurized. Any reading less that ZERO is shown in percent
leak. This is the measured air escaping the pressurized cylinder. A very
tight engine has less than 4% leakdown. One with considerable pressure loss
in need of repairs will have more than 20% leakage.

Need to know more?

This test is not a reliable test for a leaking head gasket. Shop line
pressure is only 120 psi while a running engine is considerably more at the
moment of peak combustion pressure.

--

- Philip

"Philip" <1chip-state1@earthlink.n0t> wrote in message
news:oO6Yd.763$qf2.378@newsread2.news.atl.earthlink.net...[color=blue]
> Ray O wrote:[color=green]
>> A cylinder leak-down test is slightly more involved but not that
>> difficult either if you have the proper tools. Basically, you remove
>> a spark plug and install a pressure gauge in the spark plug port and
>> crank the engine over. Then you remove the gauge, squirt some oil in,
>> and repeat to see if the readings change drastically. A change might
>> indicate a piston ring problem. If the readings are equally low wet
>> or dry, then a valve not seating properly is probably the culprit. If
>> you're burning oil and the rings are good, then valve stem seals
>> are probably the culprit.[/color]
>
> RayO... BZZZZZZZZZZZZZZZZZZZZzT
>
> You have described a "compression test." (dry test followed by wet test).
>
> A "Cylinder Leakdown Test" is quite a different procedure.
>
> A pressure gauge with an adjustable pressure regulator is needed. This is
> a
> special tool
>
> The crank shaft is positioned at TDC (starting with #1) and secured so
> that
> it cannot turn. Spark plug is removed. Hose adaptor to pressure gauge
> installed. Pressure gauge is calibrated using the pressure regulator to
> the
> available shop air pressure line. Gauge is connected to the adaptor hose.
> Cylinder is pressurized. Any reading less that ZERO is shown in percent
> leak. This is the measured air escaping the pressurized cylinder. A very
> tight engine has less than 4% leakdown. One with considerable pressure
> loss
> in need of repairs will have more than 20% leakage.
>
> Need to know more?
>
> This test is not a reliable test for a leaking head gasket. Shop line
> pressure is only 120 psi while a running engine is considerably more at
> the moment of peak combustion pressure.
>
> --
>
> - Philip
>[/color]
Philip,

Thanks for the reminder, I already corrected my earlier post. And they say
the eyes are the first thing to go! It seems like I've been having more
than my share of brain farts recently!
--
Ray O
correct the return address punctuation to reply

Ray O wrote:
[color=blue]
> "Tercel Owner" <Toyota@Tercel.com> wrote in message
> news:4230BEBB.E1C1E7CF@Tercel.com...[color=green]
> >
> > It turns out that pressure testing the cooling system and the leak-down
> > test is not
> > too involved (for a professional mechanic's shop), and it was done. No
> > problems.
> > The leak-down test gave less than 10% (I'm not sure of what), which is
> > suppose
> > to be good; 20% is considered acceptable. I'll ask about whether he
> > listened for
> > hissing or checked for coolant bubbles when I pick up the car.[/color]
>
> If the engine is holding air that tightly, it is not very unlikely that
> there is a head gasket leak, which would cause the bubbling in the coolant.[/color]

Bit confused by "not very unlikely". Do you mean "not very likely"?

[color=blue]
> Another sign of a head gasket leak is oil in the coolant or coolant in the
> oil. In the case of coolant in the oil, the oil will have a milky
> appearance.[/color]

Yes, and I have checked for this. It doesn't appear to be the case. My
mechanic also mentioned this symptom, and said it was absent.

[color=blue]
> I hope he isn't too[color=green]
> > aggravated by my telling him how to do his job. He says that the symptoms
> > don't
> > really indicate the kind of problem that these tests would track down. In
> > fact, this
> > same oddity was expressed by the person who told me about the leak-down
> > tests.
> >[/color]
> True, which is why I had recommended that you let your technician diagnose
> the cause of the odor.[/color]

I left a phone message saying that I don't presume to be able to advise him on
the best course of action, and that these were just ideas that came up in discussion.
I also mentioned that the person that introduced the idea of a leak-down test also
was puzzled by the disparity between the actual symptoms and those symptoms
which the test was suppose to troubleshoot. Basically, I left it the judgement up
to the mechanic. The guy who told me about the leak-down test thinks it is actually
oil dripping externally onto a hot part of the exhaust system, and I forwarded this
to the mechanic in case he thought I was bent on having him do a leak-down test
against his better judgement. Externally dripping oil theory makes perfect sense,
since that's the most convincing explanation for how fumes are getting into the
people-compartment. Even though it is the best explanation, it still has some
difficulties. For example, the gasket around the hood is in place, so it is strange
that the fumes can get to the vent intakes below the wipers.

As I said, the mechanic said he did those tests, and no problems came up. I asked
if he did it just to appease me, and the answer was yes. I think he went beyond the
call of duty to be accommodating. The labour was covered by the engine warranty.

Tercel Owner

Ray O wrote:[color=blue]
> "Philip" <1chip-state1@earthlink.n0t> wrote in message
> news:oO6Yd.763$qf2.378@newsread2.news.atl.earthlink.net...[color=green]
>> Ray O wrote:[color=darkred]
>>> A cylinder leak-down test is slightly more involved but not that
>>> difficult either if you have the proper tools. Basically, you
>>> remove a spark plug and install a pressure gauge in the spark plug port
>>> and
>>> crank the engine over. Then you remove the gauge, squirt some oil
>>> in, and repeat to see if the readings change drastically. A change
>>> might indicate a piston ring problem. If the readings are equally
>>> low wet or dry, then a valve not seating properly is probably the
>>> culprit.
>>> If you're burning oil and the rings are good, then valve stem seals
>>> are probably the culprit.[/color]
>>
>> RayO... BZZZZZZZZZZZZZZZZZZZZzT
>>
>> You have described a "compression test." (dry test followed by wet
>> test). A "Cylinder Leakdown Test" is quite a different procedure.
>>
>> A pressure gauge with an adjustable pressure regulator is needed. This is
>> a
>> special tool
>>
>> The crank shaft is positioned at TDC (starting with #1) and secured
>> so that
>> it cannot turn. Spark plug is removed. Hose adaptor to pressure
>> gauge installed. Pressure gauge is calibrated using the pressure
>> regulator to the
>> available shop air pressure line. Gauge is connected to the adaptor
>> hose. Cylinder is pressurized. Any reading less that ZERO is shown
>> in percent leak. This is the measured air escaping the pressurized
>> cylinder. A very tight engine has less than 4% leakdown. One with
>> considerable pressure loss
>> in need of repairs will have more than 20% leakage.
>>
>> Need to know more?
>>
>> This test is not a reliable test for a leaking head gasket. Shop
>> line pressure is only 120 psi while a running engine is considerably
>> more at the moment of peak combustion pressure.
>>
>> --
>>
>> - Philip
>>[/color]
> Philip,
>
> Thanks for the reminder, I already corrected my earlier post. And
> they say the eyes are the first thing to go! It seems like I've been
> having more than my share of brain farts recently![/color]

Is Beano available as an injectable? I'll try some too! LOL
--

- Philip

Philip wrote:
[color=blue]
> A "Cylinder Leakdown Test" is quite a different procedure.
>
> A pressure gauge with an adjustable pressure regulator is needed. This is a
> special tool
>
> The crank shaft is positioned at TDC (starting with #1) and secured so that
> it cannot turn. Spark plug is removed. Hose adaptor to pressure gauge
> installed. Pressure gauge is calibrated using the pressure regulator to the
> available shop air pressure line. Gauge is connected to the adaptor hose.
> Cylinder is pressurized. Any reading less that ZERO is shown in percent
> leak. This is the measured air escaping the pressurized cylinder. A very
> tight engine has less than 4% leakdown. One with considerable pressure loss
> in need of repairs will have more than 20% leakage.
>
> Need to know more?
>
> This test is not a reliable test for a leaking head gasket. Shop line
> pressure is only 120 psi while a running engine is considerably more at the
> moment of peak combustion pressure.[/color]

Yes, I believe he said the shop air was between 90psi & some high number
(120 to 150, can't remember). He also said that in actual operation, the
pressure actually approaches 200psi or more, so any problem caught by
the leakdown test would have shown up big time in normal operation.
He described an example whose details I'm trying to recall. Something
about pressurizing the coolant, and causing it to overflow.

When he did the test, he had the valves disengaged from the cam shaft.
I guess this was part of changing the valve seals. So the piston didn't
have to be at TDC for input & output valves to be closed. He could
quickly test the each cylinder one after another for 5 minutes each. Leakage
varied between 8% and 9%. Since the valve cover was off, he didn't
bother trying to listen for hissing at the hole for topping off engine oil. He
also casually mentioned quickly listening for air at the intake and exhaust.

One thing I didn't clarify was whether the leak-down test was done
before or after the valve seals were replaced.

The old valve seals were quite hard, and the inside diameter was
wider than new valve seals by enough to be discernible to the
naked eye. He is sure that the old valve seals were responsible for
the black sooty exhaust during the first 10 seconds of engine operation.
When the car is turned off for some time, oil leaks down to the seam
between the valve and the rest of the combustion chamber. When the
engine is started, the oil gets drawn into the combustion chamber.
The fact that the exhaust is black rather than blue is not unusual, even
though black is often an indication that there is too much gas in the
mixture.

He also "pressure test[ed] coolant system -- check heater core for leaks,
none found....Check[ed] for external oil leaks -- none found". So much
for the theory of oil externally dripping on to a hot portion of the exahaust
system. Other things done include "flush engine & perform teradan" (can't
make out spelling of last word, but I guess it's a machine to analyze the
make-up of the exhaust), pre- & post-combustion cleaner (again,
last word not clear).

After all of that, the smell seems mostly gone, though there seems to be the
very occassional hint of it. Most of the new smell is the cleaning agents
used to clean the engine, which is quite strong, but not too bad-smelling.
It should burn away shortly. I have my fingers crossed that the problem is
gone. Only small amount of coughing since picking up the car, and that
may be psychological. Only time can tell.

I understand that it is part of the warranty, but I certainly feel that
he is putting alot of extra work into it. I only hope that it is being covered
by the place from which he got the used engine (I assume that there is a
guarantee associated with it, and that they worked out a deal in which he
makes it good, and they pay him rather than replacing the engine).

Tercel Owner

Tercel Owner wrote:
[color=blue]
> One thing I didn't clarify was whether the leak-down test was done
> before or after the valve seals were replaced.[/color]

Not that this should matter, since the valves are closed.

Tercel Owner

Tercel Owner wrote:[color=blue]
> Philip wrote:
>[color=green]
>> A "Cylinder Leakdown Test" is quite a different procedure.
>>
>> A pressure gauge with an adjustable pressure regulator is needed.
>> This is a special tool
>>
>> The crank shaft is positioned at TDC (starting with #1) and secured
>> so that it cannot turn. Spark plug is removed. Hose adaptor to
>> pressure gauge installed. Pressure gauge is calibrated using the
>> pressure regulator to the available shop air pressure line. Gauge
>> is connected to the adaptor hose. Cylinder is pressurized. Any
>> reading less that ZERO is shown in percent leak. This is the
>> measured air escaping the pressurized cylinder. A very tight engine
>> has less than 4% leakdown. One with considerable pressure loss in
>> need of repairs will have more than 20% leakage.
>>
>> Need to know more?
>>
>> This test is not a reliable test for a leaking head gasket. Shop
>> line pressure is only 120 psi while a running engine is considerably
>> more at the moment of peak combustion pressure.[/color]
>
> Yes, I believe he said the shop air was between 90psi & some high
> number (120 to 150, can't remember). He also said that in actual
> operation, the pressure actually approaches 200psi or more, so any
> problem caught by
> the leakdown test would have shown up big time in normal operation.[/color]

Actual pressure spike at peak combustion pressure is roughly 3 to 3.5 times
cranking compression. Throttle position has a considerable influence on the
peak pressure just as it does on simple cranking compression tests.

[color=blue]
> He described an example whose details I'm trying to recall. Something
> about pressurizing the coolant, and causing it to overflow.[/color]

This is a DIFFERENT test. Pressurizing only the cooling system typically
does not exceed 19-20 psi. Is administerd at the radiator cap with a special
adaptor.

[color=blue]
> When he did the test, he had the valves disengaged from the cam shaft.
> I guess this was part of changing the valve seals. So the piston
> didn't have to be at TDC for input & output valves to be closed. He
> could quickly test the each cylinder one after another for 5 minutes each.
> Leakage varied between 8% and 9%. Since the valve cover was off, he
> didn't
> bother trying to listen for hissing at the hole for topping off
> engine oil. He also casually mentioned quickly listening for air at
> the intake and exhaust.
>
> One thing I didn't clarify was whether the leak-down test was done
> before or after the valve seals were replaced.[/color]
snipped for brevity.[color=blue]
>
> Tercel Owner[/color]

Would not matter. The valve *stem* seals have NOTHING to do with the valves
sealing the combustion chamber.
--

- Philip

Philip wrote:
[color=blue]
> Tercel Owner wrote:[color=green]
> > Philip wrote:[color=darkred]
> >> Shop
> >> line pressure is only 120 psi while a running engine is considerably
> >> more at the moment of peak combustion pressure.[/color]
> >
> > Yes, I believe he said the shop air was between 90psi & some high
> > number (120 to 150, can't remember). He also said that in actual
> > operation, the pressure actually approaches 200psi or more, so any
> > problem caught by
> > the leakdown test would have shown up big time in normal operation.[/color]
>
> Actual pressure spike at peak combustion pressure is roughly 3 to 3.5 times
> cranking compression. Throttle position has a considerable influence on the
> peak pressure just as it does on simple cranking compression tests.[/color]

snip
[color=blue][color=green]
> > He described an example whose details I'm trying to recall. Something
> > about pressurizing the coolant, and causing it to overflow.[/color]
>
> This is a DIFFERENT test. Pressurizing only the cooling system typically
> does not exceed 19-20 psi. Is administerd at the radiator cap with a special
> adaptor.[/color]

It didn't seem like he was desribing a test. I think he was describing symptoms
during normal engine operation. Something about coolant overflowing into the
reservoir. He might also have said that bubbles in the coolant would show under
normal operation. Many details were mentioned, and I didn't stop him and get
clarification on all of them (just a few).
[color=blue][color=green]
> > One thing I didn't clarify was whether the leak-down test was done
> > before or after the valve seals were replaced.[/color]
>
> Would not matter. The valve *stem* seals have NOTHING to do with the valves
> sealing the combustion chamber.[/color]

Yes, I posted a follow up with that exact observation, after some thought.

Tercel Owner