[mjam0714]

1996 camry 5sfe The a/c wasn't blowing cold as it should. i finally after years of prognosticating broke out the gauges and added some 134a from a 30 lb container to the system.It would not take very much at all. the a/c started blowing warmer air. instead of just letting some out, I sucked it down and tried to reinstall from scratch. now it only takes about 5 oz of Freon, and only on the high side! I am assuming the system is clogged! now my question is where? because it will only take Freon on the high side would it be the condenser? is the condenser between the high side and the low side?

 

[Tripleguy]

Shouldn't be adding refrigerant to high side, only low side. If it leaks down too low, it won't be able to draw it in. You probably waited too long. Best to take it to a shop where they're equipped to deal with it.

 

[mjam0714]

Shouldn't be adding refrigerant to high side, only low side. If it leaks down too low, it won't be able to draw it in. You probably waited too long. Best to take it to a shop where they're equipped to deal with it.

I only added Freon on the high side because at that point i was frustrated. the system holds a vacuum, and has been working for years! If what leaks down too low? the system?

 

[Tripleguy]

If there is no refrigerant in it and the compressor wont come on it won't take a charge. The system has a low pressure switch that shuts it down if the pressure is low.

Recover - deep vac - and then charge the HIGH SIDE

If moist air was exposed to the inside of the system it wont work properly either. You really need to have it evacuated, maybe even change the drier?

 

[Stillrunning]

1996 camry 5sfe The a/c wasn't blowing cold as it should. i finally after years of prognosticating broke out the gauges and added some 134a

I assume then that the system had some pressure over those years to prevent air and moisture from getting inside?

the a/c started blowing warmer air.

So you were getting some cold but then no cold?

I sucked it down and tried to reinstall from scratch.

You pulled a vacuum with a pump for at least 1/2 hour? What vacuum did you get?

is the condenser between the high side and the low side?

The condenser is on the high side after the compressor, after the condenser is the TXV valve, after the TXV is the low side.

 

[mjam0714]

I assume then that the system had some pressure over those years to prevent air and moisture from getting inside?



So you were getting some cold but then no cold?




You pulled a vacuum with a pump for at least 1/2 hour? What vacuum did you get?



The condenser is on the high side after the compressor, after the condenser is the TXV valve, after the TXV is the low side.
[/QUOTE

i Know from prior Camry's I have owned the air was not up to their standards, so i added Freon. I am assuming when I added Freon to this system "and I only added a very small amount" it did something to the system and it stopped blowing cold and started blowing cool air. I had in prior years purchased a dryer and expansion valve for future use with the engine hot I replaced the dryer only.
I used Harbor Freight Gauges, and Vacuum pump. vacuumed for !/2 hour. What is the TXV valve?

 

[mjam0714]

The system worked it blew cold air! from owning prior Camry's I knew it was not up to par! Added small amount of Freon to system and it went from blowing Cold Air to Cool Air.

 

[mjam0714]

I assume then that the system had some pressure over those years to prevent air and moisture from getting inside?

the system worked just not up to par.

So you were getting some cold but then no cold?

Cold then cool air after adding small amount to a system that has worked for years!


You pulled a vacuum with a pump for at least 1/2 hour? What vacuum did you get?

Harbor freight Vacuum and yes !/2 hr.

The condenser is on the high side after the compressor, after the condenser is the TXV valve, after the TXV is the low side.

What is the TXV valve and can it clog up like a condensor?

 

[Stillrunning]

Harbor freight Vacuum and yes !/2 hr.

What vacuum reading did you get on the gauges?

If you vac'd out properly, and the vacuum held, then there should have been enough negative pressure in the system to automatically draw in at least one small can of refrigerant without running the compressor. The static pressure in the system then will be equal in both the low and high sides. It is recommended to do this type of fill on the high side (compressor off). Once that is done there should be enough pressure to close the low pressure switch which will allow the compressor to run, at which time you can add the required amount of refrigerant (by weight, not volume) to the system.

What is the TXV valve and can it clog up like a condensor?

The TXV is a thermo expansion valve that responds to heat transfer requirements in the system. It regulates the amount of refrigerant sprayed into the low side evaporator. It is what creates a low and high side. The valve can clog or not work and will present as a restriction in the system.

 

[OleAvalon]

What is the TXV valve and can it clog up like a condensor?

It can clog up worse than the condenser. The condenser has multiple passages, the expansion valve has only one tiny internal orifice.

The shop that did my a/c last summer (new compressor & condenser) got a particle in the system that clogged the expansion valve. Since it's buried behind 5 hours of dashboard R&R, I left it as is. Over time, flow has returned and a/c works ok, but not 100%, I'm assuming because the valve opens and closes and potentially the clog was broken up. Mostly.

 

[mjam0714]

What vacuum reading did you get on the gauges?

If you vac'd out properly, and the vacuum held, then there should have been enough negative pressure in the system to automatically draw in at least one small can of refrigerant without running the compressor. The static pressure in the system then will be equal in both the low and high sides. It is recommended to do this type of fill on the high side (compressor off). Once that is done there should be enough pressure to close the low pressure switch which will allow the compressor to run, at which time you can add the required amount of refrigerant (by weight, not volume) to the system.



The TXV is a thermo expansion valve that responds to heat transfer requirements in the system. It regulates the amount of refrigerant sprayed into the low side evaporator. It is what creates a low and high side. The valve can clog or not work and will present as a restriction in the system.

Last time I tried it vacuumed to -28 low side and pegged out negative high side. i left the engine off and opened to gauge with 30 lb container upside down on high side, the compressor ran and it stopped accepting Freon. after a while with the compressor running and low side gauge open and the Freon bottle on a scale it would not move the scale (postal scale from Harbor Freight ) zeroed out the scale with the Freon container on it.
Now that you explained the Expansion Valve and what it does in the system, i am assuming the Expansion Valve is clogged !
is the expansion Valve on the firewall on a 96 camry or is it under the dash?

 

[Stillrunning]

is the expansion Valve on the firewall on a 96 camry or is it under the dash?

The -28hg is what you want to see. I'm not sure about using a 30 LB container for initial static charge though.
That may be why you could not get any more refrigerant in. What running pressures were you getting after the initial charge - high and low?

The valve is before the evaporator - yes under the dash. Can be very difficult to get to as has been stated.

 

[Riick]

Back in the 1960's I was taught that you never charged an A/C system using fluid (tank upside down) only with gas. Reason was the compressors used reed valves (?) that could fail if fluid was used, and large slug of fluid hit valves. By time of these cars, did Toyota go to a rotary compressor? If not, compressor may now be trashed.

You explain that the system blew cold air, but not cold enough, then you added R134a, and system no longer produced any cold air. That's consistent with overcharging system, as-in adding too much refrigerant.

So what kind of pressures are you getting High & Low sides?

 

[Stillrunning]

Back in the 1960's I was taught that you never charged an A/C system using fluid (tank upside down) only with gas.

On an initial fill with system off the vacuum in the system turns the liquid to gas pretty fast. After that fill on low side with gas, but that can take a lot of time. I tend to quick turn the can up/down and wait a short bit to speed things up.

 

[mjam0714]

The -28hg is what you want to see. I'm not sure about using a 30 LB container for initial static charge though.
That may be why you could not get any more refrigerant in. What running pressures were you getting after the initial charge - high and low?

The valve is before the evaporator - yes under the dash. Can be very difficult to get to as has been sta

The -28hg is what you want to see. I'm not sure about using a 30 LB container for initial static charge though.
That may be why you could not get any more refrigerant in. What running pressures were you getting after the initial charge - high and low?

The valve is before the evaporator - yes under the dash. Can be very difficult to get to as has been stated.

5 low 100 high side after initial charge.

 

[mjam0714]

Back in the 1960's I was taught that you never charged an A/C system using fluid (tank upside down) only with gas. Reason was the compressors used reed valves (?) that could fail if fluid was used, and large slug of fluid hit valves. By time of these cars, did Toyota go to a rotary compressor? If not, compressor may now be trashed.

You explain that the system blew cold air, but not cold enough, then you added R134a, and system no longer produced any cold air. That's consistent with overcharging system, as-in adding too much refrigerant.

So what kind of pressures are you getting High & Low sides?

before I added Freon to the system the sight glass was running and idling with bubbles after adding Freon it was clearing up only when the compressor cycled off. before I added Freon to the system the pressure readings were 20 low and 200 high. after adding Freon the pressure readings went down as low as 10 low and 165 high. After removing all the Freon from the System and doing a initial charge to the system the compressor cycled on the reading were 5 low 100 high.

 

[Stillrunning]

5 low 100 high side after initial charge.

If those are your readings after what you thought was full charge then they are way to low. R134 runs at higher pressures than R12. From my FSM normal pressures should be Low = 21 to 35, High = 199 to 227 (psi)

As has been suggested I would start again with full vacuum pull for 1/2 to 3/4 hour, then do initial fill with one can to start, then continue filling from your 30 lb canister. Due to your inexperience I would take it to an A/C tech who can also reclaim the old R134 in an environmentally proper method and confirm a TXV blockage.

My take on your problem is a blocked TXV. I don't know if the system can be back blown through the TXV to maybe clear it, but you'd have to break into connections to do that and use compressor air.

Another thought might be a blocked filter/dryer since the system was unused so long - that's just a guess, but a cheap fix.

 

[CamryFL]

Last time I tried it vacuumed to -28 low side and pegged out negative high side.

5 low 100 high side after initial charge.

That would indicate a connection leak, while attempting to do the initial recharge of the system (been there, done that), and/or a blockage.

The Receiver/Dryer would be the first & most obvious item to diag/replace and re-attempt the procedure. ... +1 on having a shop w/ proper equipment doing the evac / reclaim on refrigerant, before another attempt.

 

[mjam0714]

If those are your readings after what you thought was full charge then they are way to low. R134 runs at higher pressures than R12. From my FSM normal pressures should be Low = 21 to 35, High = 199 to 227 (psi)

As has been suggested I would start again with full vacuum pull for 1/2 to 3/4 hour, then do initial fill with one can to start, then continue filling from your 30 lb canister. Due to your inexperience I would take it to an A/C tech who can also reclaim the old R134 in an environmentally proper method and confirm a TXV blockage.

My take on your problem is a blocked TXV. I don't know if the system can be back blown through the TXV to maybe clear it, but you'd have to break into connections to do that and use compressor air.

Another thought might be a blocked filter/dryer since the system was unused so long - that's just a guess, but a cheap fix.

ok I guess I'm going to attempt to back blow the TXV ! then I will try a initial fill with a can of Freon. if that doesn't work it looks like a 2 week dash removal !!
yes I said 2 weeks I'm a little older than I used to be ! LOL

 

[mjam0714]

oh buy the way the first thing i did was replace the dryer.