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Schrader valve defective? Porsche 964 small a/c leak problem!
Hello. I am a new to here, but I've been digging around Rennlist so much times for last decade.
Ok, Mine is Early 90 964 C4 cab and 108,000 on it. Everything was recovered, especially I've been fighting for a/c problem.
Until on May, it was perfectly freezing, but now warm air is blowing all of sudden.
I have replaced lo/hi schrader valves.(r12 type abolutely) on last year December.
Problem is again at six months.
What do you think my friends?
Overpressure?
Defective schrader valve?
Other things?
Who knows? It appears that after 30 years many of our cars have slow leaks somewhere. Anecdotally, many site leaks at the expansion valve. R-mm and I are taking the totally change every seal in the system approach including some components as we convert our cars to R134a. I am also going to rebuild my compressor with a seal kit. So you have UV dye in your system now?
I also noticed some dye around my fill ports so I am replacing mine too. Apparently the schrader valves are a common failure point for ACs in general, but as others have noted there are plenty of places to look for leaks in a 964.
You are just replacing the valve insert, correct? Not he outer housing with the threads. I am about to reseal my compressor and this makes sense to add to my To-Do list.
You are just replacing the valve insert, correct? Not he outer housing with the threads. I am about to reseal my compressor and this makes sense to add to my To-Do list.
Yes I replaced just schrader valve only.
You know what housing is too expensive, but I strongly agree that housing's r12 outer line is probably worn out?
I told my friend's Porsche dealer to quote a housing price. (I think whether it is stock or not)
Last edited by #bylee_car_geek; 06-16-2020 at 05:21 PM.
Interesting thought on the valve being the culprit and now I wonder if mine has the same issue. My shop pulled vacuum on the system and it held but this would never confirm if the valve is leaking since it’s depressed during testing. I may have mine changed as well before recharging it.
Interesting thought on the valve being the culprit and now I wonder if mine has the same issue. My shop pulled vacuum on the system and it held but this would never confirm if the valve is leaking since it’s depressed during testing. I may have mine changed as well before recharging it.
Marine Blue, yeah I want to say it's a moon talk, but dye came out and ruined valve cap.
Normally small leakage's vacuum test is not movable, as far as I know.
Well.. I'll replace the another schrader valve re-charge the R-134 again.
Replacing the cores is easy, there are tools to do so without loosing pressure even. Keep in mind that some refrigerant therefore dye always comes out when you attach/remove the gauges therefore seeing dye there is to be expected. If you want to be double sure you didn't mess up the valves you can get a torque screwdriver and follow the valve core specs.
Replacing the cores is easy, there are tools to do so without loosing pressure even. Keep in mind that some refrigerant therefore dye always comes out when you attach/remove the gauges therefore seeing dye there is to be expected. If you want to be double sure you didn't mess up the valves you can get a torque screwdriver and follow the valve core specs.
Thanks for this info, very helpful! How is it that the valve won’t leak when changing the core? I guess I should disassemble one to understand better.
There are fancy tools designed to allow you to replace valves while not releasing pressure however I sincerely doubt the tool would fit the high pressure port it may fit the low pressure port but regardless it is pretty simple to evacuate the system before changing
06-16-2020, 09:35 AM
Schrader valve defective? Porsche 964 small a/c leak problem!
