tm33133

I've been following alot of the air con threads and can't seem to find an answer to my issues.

before I pay someone to rip out my dash to replace the evaporator [and buy a rebuilt compress] was wondering whether anyone has any other ideas. Not sure how much of this is relevant, but

1 The ac cools sometimes and at other times doesnt. The clutch seems to engage in both cases . always check the ec switch, that's not the issue.

2 The problem usually happens when the engine is hot and the car has been sitting in the sun.

3 Had evap sensor replaced

4. had it recharged with refrigerant and there may be a slow leak somewhere, probably evaporator, according to mechanic who used an electonic leak detector and couldnt find anything. compressor wasnt engaging at the time.

5. Also, had a clogged ac drain tube that was cleaned out. Water was spilling into the drivers side footwell.

6 Fan works and when ac is not cooling I get a smell from the vents, mold and maybe oil.

7. yesterday, after the AC had been out for awhile, I ran the heater on hi for 30 minutes. The next day the AC was working again.

I'm hoping there is an easy, relatively cheap answer, but I'm not finding any.

stim141

I don't get it - you took it to a AC guy and they found nothing yet the system still doesn't work properly? Did you do the climate control display diags? What are your pressures/temps - need to know the bar and evap temps as well as the outside temps to determine what is going on.

If he used a leak detector and found nothing why do you think you need an evaporator? The temps are important because it will help determining if you have a stuck duovalve (controls the coolant into the cabin (heat). Check your in cabin filter and replace it.

If the pressures are fine then you don't have a leak - how much was added when it was topped off. Did they say the operating pressures were to spec.

Last summer I thought my compressor was dying or something else that costs a ton of money was going. Took it to a AC guy who only does AC - said I was low by a really small amount of freon. Charged it after an evac, pull. Got temps out of the evaporator with outside temps in the 100F range to 36-38F which for a car this old is REALLY great. Cost was only 80 to do the service + freon. Total cost about 100. Compressor is strong, etc.

tm33133

Thanks for the reply.

Reason he thinks there's a leak is that refrigerant level is down by 20% after being filled this summer.

Reason he thinks it's a slow leak in evaporator is no leak detected elsewhere and oil smell from vents.

Compressor wasnt cooling when he looked at it

Readings when the ac works are like this at start

#1 Inside 77
#2 Outside 79
#3 Left core 54
#4 Right core 55
#5 Evaporator 136
#6 Coolant 171
#7 Refrig press 10
#8 Refrigtemp 88

I'm wondering whether drain tube blockage and water backing up can result in this intermittent failure

stim141

#7 is a little low and your number 5 is totally off - should reflect temperature of a cool evaporator and ranges from in the mid 30's when working perfectly to in the low 40's. Possibly a bad sensor. Don't remember if the thing is screwed into the evaporator - if the sensor is leaking that could be your problem - maybe.

Dash removal according to the dealership isn't that big of a deal - you have pull a bunch of things but the wiring is very neatly stowed. I did a VW Gti VR6 a few years ago in December temps and it was a major PITA - wiring wasn't clipped down and not wrapped. Getting it back together to even come close to a factory install was impossible. 90's Jags are REALLY bad!

MarcusF

Good news. If it is the evaporator temperature, the dash doesn’t come out. The sensor is accessed by removing the cover under the driver’s side foot well. The first photo (neither photo are mine) was shot looking straight up while laying in the foot well and is what you would see laying on your back.

For orientation:
The yellow circle is the top of the accelerator pedal arm.

The red circle is the part in question.

The part is displayed in the second photo.

Autohaus AZ has the sensor. $36 for the OEM part or $26 for a non-OEM version.

I hope that helps.

etownbala

I would check and potentially clean the duo valve just to rule it out. Cheap clean/fix.

KRis

Lorenzo

where is the duo valve

etownbala

Upper passenger side of engine bay near the window...near the fuse box.

johnaresch

Sounds like some one in the know. My 2000 CLK 320 with 130,000 miles AC blows hot hot hot


no error msgs
but when checked for sensor readings this is what came up.


#1 Inside102
#2 Outside 92
#3 Left core 108
#4 Right core 108
#5 Evaporator 104
#6 Coolant 199
#7 Refrig press 7


Any help greatly appreciated. When got off the shelf ac charge kit showed I was in pressure alert area, but sensor reading doesn't indicate that.


Hot in florida right now so top is down


Thanks for any help.

miatawnt2b

Looks like everything is normal... I'd jump the compressor to see if starts pumping cold. If not, you'll need a new one.

johnaresch

Ugh, was wishing it was one of those 36.00 sensors. When looking in engine, while car running but parked and blocked compressor is spinning...How hard is a compressor pull and replacement. I just finished a CPK on my wife's car 2007 C280 4 matic and that was a bear. is the compressor of equal or harder effort.