Das AMG

I need an experienced person to give me some advice. I have some experience on this a.c system based on digesting as much info on the internet as I dared about the W210 a.c system. In my past life I rebuilt 911 engines, but no experience with a/c. Why don't I bite the bullet and take it to the dealer? Well, that means I wouldn't gain the experience and have the fun and satisfaction, AND the real reason...
most mechanics are incompetent (and destructive) just replacing thing$ until the problem goes away. I do know my limitations and my philosophy is to do no harm.

Most information I encountered is either bad, misleading, or mostly clueless. It seems most people can't even find the high pressure port. I found some poor fools recharging through the high pressure side. So as a last resort to get up to speed I RTFM (read the f'ing manual).

I've run a diagnosis using the climate control buttons. It shows low refrigerant, 3 bars. The only FAULT that is picked up is B1419 electromagnetic clutch. This is expected because of low refrigerant and so the clutch will not engage the compressor. By the way my econo button does NOT light as expected for low 134a pressure. It will light when I put it in econo mode.

One interesting thing is that the high pressure port's schrader valve leaks pressure. I noticed this when I removed the cap. The cap is a backup seal and may seal the system even though the valve leaks. Not a problem that I'm going to deal with now.

My system was nearly empty of refrigerant, not good, but the car is 15 years old so probably normal behavior.

I used manifold gauges with a vacuum pump to attempt to fully recharge my a/c system. This process is simple and straight-forward enough. It is not rocket science.

The system will not hold a vacuum. Now wait ... this does not necessarily imply that there is a leak in the system. I tested the manifold gauges and found that they leak vacuum even when the gauges are not attached to the car. This Is probably normal? The lines are attached okay and the pump is working fine. Could be the manifold gauges are bad but I doubt it.


I may try another set of manifold gauges.

Any thoughts ......

Das AMG

What, no reply from this sleepy little forum?

bluechipbenz

Don't know anything about this, but that's a hell of a way to reach out to people who could potentially help you.

benzokirk

what he said ^ +10

I think the reason you're not getting any responses is that, while most of us do our own work on our cars, AC isn't an item high on the DYI list for us.

As for you slamming us as a "sleepy little forum" if you check posts on other subjects you'll find a fair amount of responses on various issues.

NAFT1

I'd tackle that faulty schrader valve now; lubricant is mixed with refrigerant, so it's bad for the compressor when the mixture is low. Can't remember if the compressor is clutched or if it is variable volume like my Audi;if it is the latter it compounds the damage done on low refrigerant.

tantinjan

See my profile photo album i got A/C recharge values for gauge low / high pressure.With some fault finding.

tantinjan

A /c system should hold pressure after vacuum is been pull . if not you got a leak .Most of the time it is the o rings .Good practice to replace the ones you can get to .With re gas put a/c oil in they leak out with the gas if there is a leak.OILY patch on a/c system indication of oil leak.To much oil and the system will not cool down to max to little and you risk of seize compressor.A dye in the oil will show future oil leaks test with ultra violet light.

Schweinhund

You would probably do better in the non-AMG forum. Although our cars are substantially modified, the AC-system is not- its like all the rest and there is a lot more activity over there.

But, FWIW, get that valve replaced.

michalk

I am troubleshooting my system, and I charged my buddies system. First, I got myself a DAS, and that's helped me get comfortable with what's going on here.

My car evaporator won't get down into the <6C range. I still haven't fully figured out what's wrong with mine. However, my buddy drives a CLS550, and his was low on freon. I connected my gauges, set the compressor to 70%, turned the A/C on to max, and measured subcooling. His was plainly obvious even without measuring the subcooling that it was low on freon.

I applied the procedure that I found elsewhere on the net, but the objective is to get the A/C into a stable operating mode, then add freon until the performance levels out. I added freon to the low side very slowly, meaning one 12oz can over about two minutes. My buddy read off the evaporator temperature while I watched the gauges. At the end of the first can, the evap temp was still dropping. So, we began to add a second can. When the evap temp rate of change begins to slow down, then the A/C is full. I measured subcool again, and it was within the ballpark figures I've read about elsewhere : 8F.

To do it right, you need to evacuate it, then recharge by weight. If you have the tools, I think you can get within 10% of correct.

My buddy came in with evap temps around 25C. He pulled out of my driveway with evap temps at 8C. He called me from the road, and was getting 1C.

I wish my car responded like his. For some reason mine is showing a good charge, and good subcool, but the compressor is throttling itself.

Das AMG

It's been 3 weeks since I solved the A/C problem.

For the benefit of others with AC problems here is what happened --

Replaced the leaking high pressure port.

The system fault said magnetic clutch fault. Turns out the compressor clutch was bad. It would not engage the compressor. Compressor was 15 years old so time to get a new compressor.

I bought a new oem "Denso" compressor from Pelican Parts for $385 and new Drier.
Installed the new compressor and Drier, then evacuated and recharged with 1 Kg of r134a refrigerant.

Started engine and new compressor engaged, thermometer got down to 34F degrees. AC has been working fine so far with no problems. What a relief in this hot Washington metro area heat and humidity.

I thinked I lucked out because it was a straight-forward fix. Every time I get behind the wheel I realize what an incredible car, this E55 AMG. I love the face-melting, hand-of-god surge of power and performance from this big sedan.

Thanks to all for the helpful advice. I apologize for my rocky start in this thread, chalk it up to frustration and impatience. It's all good now.

mrobinso

Appreciate you posting up the solution to your problem and glad you got it fixed, and for a relative bargain by doing it yourself. I always try to post up the solution if I have started a thread - I can't tell you how many times I have read through a thread thinking "This sounds identical to my problem!" only to get to the end to find that the OP never posted an update . Enjoy that cold AC - someone will thank you for this info later!

trinitony

lol..this aint rennlist or pelican..

Schweinhund

Thanks for the follow-up. I am impressed you did the AC yourself. That is something I have always avoided on every car I've owned!