Oil leak additive effectiveness and related question

My 1986 Camry had been burning about a quart of oil every 500 miles. Last
Monday, I filled it with oil at least up to the oil dipstick full mark,
probably past it.

The next day, about noon, after having driven it about 300 miles, I noticed
that oil was leaking off the engine somewhere, quite likely at the
camshaft's oil seal. While it's possible the leak is coming from the oil pan
gasket, it probably isn't. It's hard for me to tell because I can't easily
prop up the car, and it's been cold and wet here. The leak seemed to develop
fairly suddenly.

If the camshaft oil seal IS leaking, it looks to me like this would be quite
an expensive, labor-intensive repair.

I've seen that auto parts stores sell additives that can be added to motor
oil that supposedly stop or slow oil leaks through seals. I'm interested in
feedback about the effectiveness of these additives - or the lack thereof.
And does anyone have any particular brand(s) or these additives to
recommend - or warn me away from?

A related question - can anyone think of a scenario where overfilling the
oil level might lead to an oil leak. For example, by increasing the oil pump
pressure enough to cause a leak at a weakening point in a seal?

Thanks. Any help would be much appreciated.

Mike

(I posted this on alt.autos.toyota.camry yesterday; I post it here for wider
circulation.)

"M. Hamill" <mhamill@fuse.net> wrote in message
news:79f8a$43a6a5af$d8441f84$9633@FUSE.NET...[color=blue]
> My 1986 Camry had been burning about a quart of oil every 500 miles. Last
> Monday, I filled it with oil at least up to the oil dipstick full mark,
> probably past it.
>
> The next day, about noon, after having driven it about 300 miles, I
> noticed
> that oil was leaking off the engine somewhere, quite likely at the
> camshaft's oil seal. While it's possible the leak is coming from the oil
> pan
> gasket, it probably isn't. It's hard for me to tell because I can't easily
> prop up the car, and it's been cold and wet here. The leak seemed to
> develop
> fairly suddenly.
>
> If the camshaft oil seal IS leaking, it looks to me like this would be
> quite
> an expensive, labor-intensive repair.[/color]

Another possibility is the distributor shaft O-ring, which is a relatively
easy thing to repair. Just make sure the distributor is timed correctly
when replacing it.
[color=blue]
>
> I've seen that auto parts stores sell additives that can be added to motor
> oil that supposedly stop or slow oil leaks through seals. I'm interested
> in
> feedback about the effectiveness of these additives - or the lack thereof.
> And does anyone have any particular brand(s) or these additives to
> recommend - or warn me away from?[/color]

Generally, I do not recommend using any kinds of leak-stopping additives,
whether to the engine oil or cooling system because they may clog internal
passages. There are circumstances where it is worth trying, like on a 20
year old car that the owner does not intend to keep for long anyway.
[color=blue]
>
> A related question - can anyone think of a scenario where overfilling the
> oil level might lead to an oil leak. For example, by increasing the oil
> pump
> pressure enough to cause a leak at a weakening point in a seal?
>
> Thanks. Any help would be much appreciated.
>
> Mike
>
> (I posted this on alt.autos.toyota.camry yesterday; I post it here for
> wider circulation.)[/color]
Overfilling the engine oil generally will not lead to an oil leak.
--
Ray O
correct the return address punctuation to reply

How expensive is it to replace the valve seals? Does that require the
head being off? If they replace those, can they replace all seals that
could possibly be leaking?

I have a 11 year old car that burns some oil....about 1 qt / 3000 even
with the "max life" oil added.

"st-bum" <kennykabuki@yahoo.com> wrote in message
news:1135012231.592299.34890@g43g2000cwa.googlegroups.com...[color=blue]
> How expensive is it to replace the valve seals? Does that require the
> head being off? If they replace those, can they replace all seals that
> could possibly be leaking?
>
> I have a 11 year old car that burns some oil....about 1 qt / 3000 even
> with the "max life" oil added.
>[/color]

Assuming you are talking about valve stem seals, the answer depends a lot on
the engine. The more cylinders and valves per cylinder, the more expensive
it will be, and V-6 or V-8 engines will cost more than an in-line 4 or
cylinder engine. Engines with stuff obstructing access to the valve cover
will be more expensive than engines with unobstructed access.

For most engines, the valve stem seals can be replaced without having to
remove the head.

Replacing all seals that could possibly be leaking is very expensive and is
a lot more involved. Possibilities include valve cover gaskets, distributor
o-rings, front and rear crankshaft seals, camshaft seals on some engines,
head gaskets, and oil pan gaskets.
--
Ray O
correct the return address punctuation to reply

snip
[color=blue]
> I've seen that auto parts stores sell additives that can be added to motor
> oil that supposedly stop or slow oil leaks through seals. I'm interested
> in
> feedback about the effectiveness of these additives - or the lack thereof.
> And does anyone have any particular brand(s) or these additives to
> recommend - or warn me away from?[/color]

I don't know what you are using for oil but, before trying to use additives,
try using a heavier weight oil, like 10W40, 15W40 or even 20WX0 just to see
if it helps.