engindin

Hi all,

I read all the related treads and planning to change my A/C compressor but still questions in my mind...





A/C was blowing cool air but it was not enough (70to77 F) so at first I thought it may be low of refrigerant and I add some but then system just went off and had to remove some. I summarized what I did and observed below;





1) A/C was blowing not cold enough, I check the low side pressure and it was 60 to 80 PSI. In secret menu, "07-Refrigerant sensor" was showing 15bar so I filled the system with 134a.

2) A/C turned itself off (protection) ref. sensor was showing 21bar last moments and air was not cool enough also. low side pressure was 100PSI

3)Went to local A/C shop, ask them to remove most of the gas. He removed and told me that my compressor is bad but I didn't trust him because he is not familiar with this kind of A/C

4)Came back to my garage, started to fill R134a with small amount in between adding also small oil. A/C kicked in when ref.sensor was at 7bars. Low pressure side was again 60 to 80 PSI. this time coolant performance was better of all time but still was not enough

5)continued to filling, and reached ref.sensor 19bar and stopped. Cooling Performance is very bad.





So I have new compressor, drier and expansion valve but I don't want to change a working compressor(its a big work).




Can we rely on pressure sensor which is showing compressor is doing its job? Is it possible that it is just a bad expansion valve or something else(elec. sensor)?

​​​​​

tusabes

Drain the system again and recharge with envirosafe

it's http://www.es-refrigerants.com/products/w/id/310/t/alternate-ac-recharge-kit--refrigerant-equivalent-to-598-oz-134a/details.asp

super cold I use it in all my cars , and owners of older mercedes use it in them old systems as it works so much better and doesn't leak out

I bet you won't need to change any of your AC components

engindin

Thanks Tusabes but i believe it wont help, i need 20-25 F cooler, there must be another problem.

amstel78

If the compressor is OK and depending on ambient temps, you should be seeing between 25-55 psi on the low pressure side, and 155-340 psi on the high side. When I recharged my system because of warmish air coming out of the rear passenger ducts, I stopped refilling when pressures where around 35 psi on the low side and around 160 on the high. Ambient temp was 75-77ish that day.

If after refilling the system and pressures are good, perhaps the duovalves, front under the cowling, or rear duovalve by the front passenger wheel well are bad.

tusabes

you won't know if it will help if you don't try

DrDoe

tusabes,
When you said "super cold", do you know what temperature it's blowing in LO fresh air mode?
I trust you but I want to have a number that I can compare to my current system: it's blowing constant 41F.

tusabes

I haven't measured it with a thermometer but it's probably in the 30s

engindin

Thank you all, turns that compressor was bad. I changed together with drier and expansion valve and it is okay now.


to whom planning to do the job; be careful with 2 allen bolts that connects high/low lines to compressor