Got a 2008 gl450 90,000 mi with a a/c issue, It is blowing out warm air, so far I vacuumed it an recharged it to specs, tested pressures and read 100 on discharge side and 65 to 70 on suction side, I don't believe I have a Leak! I put a scanner on system

This is what i read through the scanner
but this should not affect my temps? Scanner also said pannel was ok! Rcv valve? This unit does not help a txv valve?where can I get a book on the whole system layout? thank you!

 

The two pressures being similar is a symptom of a worn compressor, no?

 

Having similar issues. 09 GL320. After evac and light charge. My pressure's are the same as before. low side 85, high 150 no codes, just hot air. So what the best replacement compressor reman or?

 

you can not go wrong with Denso. Around $400 for brand new one. Part # 471-1594, but 471-1436 also works, which is about $70 cheaper. Just pay attention to the oil balancing.
You need to replace the dryer as well, I chose behr 2518350047. Both dryer and compressor are the original manufactures for Mercedes.

 

Certainly, my is GL550. Please double check yours.

 

I have a new compressor on the way 465.00 hard to find, I really no better than to trow parts at a car problem, I really believe its the rcv or actuator valve on the compressor, but Im real busy and just no time right now to troubleshoot, so I guess I have to pay !

 

Initially, I thought it was control valve, I did purchased it and try to replace it w/o take out the compressor. It it not possible. The power string tube blocked the valve. I still need to loose the compressor, and replaced control vale, but no luck. I did have bad compressor.

 

not in a static situation, for example when shut off for a while - or when the compressor is not running for some reason. If running; then yes.

OP: 100 on high side is way low, and 65 on low side is way high. That could be an indication of a failed compressor or control valve IF those readings were taken with the compressor engaged.

Make sure you have compressor engagement before you go and replace it. Ensure there are no trouble codes for air temperature sensors or blowers and pressure sensor.

 

Does anyone measure pressures static?!? I was under the impression compressor running is the default.

If the compressor is not running, shouldn't the pressures be identical?

 

Static pressure is an indicator of an over/under/rightcharged system. You'd measure that with the car off for some time. What you'd expect to see there are equal low and high side pressures, in line with the pressure/temperature chart for R134. If the compressor is not running and the pressures have had time to equalize, and they are not - then there's a blockage somewhere. What's not clear from OP is during what condition these readings were taken.

 

Good info. I'm a little skeptical of the ability to diagnose fill based on static pressure, though. Seems to me with increasing fill, you'd see a rising pressure up to the point that some of the refrigerant is in liquid form, and after that, no increase in pressure (until the system is grossly overfilled and physically will not accept any more).

 

Thanks to you guys, and 460 George Washington's, the compressor warehouse , it was replaced took me some searching, but got it! replaced it and filter dryer, charged it, its too cold now! it could have been the valve on back but , no time to experiment ! thanks again guys !

 

Do the Denso compressors really vary by part number? I've seen 471-1441 is the part for my 2009 GL320 (on the DensoProducts.com Web site), but I've also seen other part numbers referenced such as 471-1594 and 471-1436. Any practical difference? I'm trying not to buy an aftermarket one.

 

Not sure about 471-1441, but 471-1594 and 471-1436 are same.