84 300SD a/c issues still - PeachParts Mercedes-Benz Forum

Joepilot · #1 03-08-2006, 08:17 PM

Hi, All been very busy trying to get the a/c going in this car.. When I got the car it had a seized compressor. Thats all I know of its history.. Here is what I did....

Put in a rebuilt compressor, Dryer, and expansion valve..I flushed out all the lines and the evaparator.. and vacuumed the system and refilled with R134. the compressor engages but its not blowing cold air... I was told its probably the evaparator, but of course I want try everything I can before that adventure..#1 when I flushed out the evaparator liquid did come out the other end and it doesnt leak...how can I be sure its the evaparator first before I R/R it????
Is there a possibility there is something near the evaparator that is directing heat mixed with cold air making it appear to not be circulating... Im at a loss..does anyone have any suggestions at this point..have I done everything that I can without pulling out the evaparator... thakns in advance... JOE

dannym · #2 03-08-2006, 10:13 PM

I would look at the condenser before the evaporator.Acording to your post you neither replaced or flushed it.

How much oil did you add?
How much refrigerant did you add?
What are your high and low side pressures?

Danny

Matt L · #3 03-08-2006, 11:32 PM

If the refridgerant is evaporating in the evaporator, you will have colder air than otherwise. Evaporators generally fail by leaking, and never by failing to actually evaporate the refridgerant. The expansion valve is much more likely to cause trouble.

I assume that you didn't check the pressures with the compressor running. Do that first, otherwise you're completely in the dark.

Joepilot · #4 03-09-2006, 01:24 PM

Hi, I did flush both the condenser and evaparator... still warm air

dannym · #5 03-09-2006, 03:13 PM

How much oil did you add?
How much refrigerant did you add?
What are your high and low side pressures?

AFIK when you get the Black Death and you don't replace the condenser your just asking for trouble.

Danny

boneheaddoctor · #6 03-09-2006, 03:17 PM

You need to add ambient temps also to coorelate to the refigerant chart.

Joepilot · #7 03-09-2006, 09:50 PM

low side 25 psi, high side 125..... I was told the evaparator is more likely to go before the condensor... the condensor is much easier to replace. maybe replace the condensor first and see if it works what do you all think..

Diesel Giant · #8 03-09-2006, 10:00 PM

Check this out for a good overview on how to do the ac.

http://dieselgiant.com/repairyourac.htm

Matt L · #9 03-10-2006, 10:03 AM

Quote:

Originally Posted by Joepilot

low side 25 psi, high side 125..... I was told the evaparator is more likely to go before the condensor... the condensor is much easier to replace. maybe replace the condensor first and see if it works what do you all think..

Unless it was really cold outside and inside the car, you have too little refridgerant in it. Your high side should probably be a lot higher. Otherwise, the compressor or expansion valve could be bad, but I'd expect higher low-side pressures with that situation (if the refridgerant level were correct).

What was the temperature when you took these pressure readings?

dannym · #10 03-10-2006, 10:37 AM

Quote:

Originally Posted by Matt L

Unless it was really cold outside and inside the car, you have too little refridgerant in it. Your high side should probably be a lot higher. Otherwise, the compressor or expansion valve could be bad, but I'd expect higher low-side pressures with that situation (if the refridgerant level were correct).

What was the temperature when you took these pressure readings?

BHD already mentioned this. I wonder why we have to keep asking him for information? Doesn't he want us to help him?

If he would take a minute and put his location in his profile then we would know where he is and get an idea of the temperatures in his area.

DAnny