My MCS Cabrio 2005 a/c does not cool but blows ambient temp air. Also there is a plastic/metal odor from the vents when a/c or heat is on. I switched the fuse/relay and no go. Can someone give me the test procedures for this? I have a multi meter and have some experience with autos since I am a ACVW nut.

RB

 

So - No one has any help on this problem? I've spent several days searching for ways to test the a/c but nothing comes up that tells me how to test it.

 

The best thing I can think of is first test to see if your A/C has some cooling effect...

...turn on the A/C and the air recycle button, and check to see if you are getting some air flowing that is lower temp then just ambient air.

If the answer is nope... then I would have a A/C specialist check the condition of your system. Put it under pressure and check for leaks.

With a 2005 we are getting into the age where things are just going to wear out, like seals and seams on the A/C condenser (more likely here because it is on the High Pressure side, and more subject to debris) but also check the Evaporator ... especially if you have a really sour smell, it is possible that there has been a lot of condensation on it and that has started to mold ... hench the bad smell. Sometimes you can turn the fan on full and spray a can a Lysol or similar (germ/mold killing) product into the fresh air inlet and it will be pulled through the evaporator and can help kill off the mold spores and freshen up the smell of the car. But you have to remember you will be blowing it into the cabin of the car, so remove small children and pets while you are doing it, or they may get overcome with the spray, having the rear hatch open will allow faster air circulation.

That is about as much as I can do at home, the rest is better off left to someone who has the correct A/C equipment to find, isolate and repair leaks.

But my money is on a hole/torn seam in the condenser.

Best of luck.

Motor on!

 

unless you have a set of, and know how to use a/c pressure gauges




I recommend to take it to someplace that does . . .

what you smell may be leaking refrigerant . . .

 

Thank you much. Some new information:

1. I have determined that the clutch turns when the a/c is on but does not
turn when the a/c is off. Sounds like the comp kicks in. Can't see the center of the clutch but the outside turns when a/c is on. I have the single button type. The light does not blink but remains on when the snowflake is pushed. Off when button is pushed again. No change when pushing the recirc button.

2. The fan behind the radiator does not turn at idle but turns when I rev the
engine for a minute or two. No overheating. Temp on gauge +/- 180 after running for 10+ min.

3. I checked the fuse in the box and all looks OK.

4. I switched out the relay in the box with another and it performs the same.

5. The smell I get is not a moldy smell but more like warm plastic or metal
smell. I get it when the heat is on too.
6. I have checked the low side pressure with the gauge on a bottle of 134A.
Reads 35# when a/c is on. Did not add any 134A.

7. The cabin air filter is not full of crap.

8. I'm pretty handy with tools and feel I should be able to R&R anything.

9. I replaced the white water pump bushing and I have a aftermarket stainless reservoir.

 

I'm pretty handy with tools and feel I should be able to R&R anything.

when I was a computer programmer I had this sign hanging in my office where I could see it ALL THE TIME

When you are sure everything is right

and the program does not work

something you are sure of is wrong

I made this sign after searching for a problem for weeks .... ignoring an area I KNEW was OK

I don't see where you checked the gas pressure

 

Thanks Cap.

I did check the low side with the gauge on the 134a bottle but not the high side.
I don't have the gauge setup. Did not add any as the pressure was 35# when running. None of my 5 ACVWs has air so don't have them but have about every other tool. The pressure does not change when the comp cycles on/off. Not sure what spec is for the low side.

Appreciate your input.

 

I just decided to put the refrigerant can and gauge on and watch the gauge to see what happened when the comp started to cycle on and off for a few minutes.

Lo and behold the damn thing started to cycle between 27# and 35#, so I added a little at a time and the damn thing started to blow cold. I added the whole freakin' can and stayed at about 40# on the top end at 68* ambient and a freeze-out inside.

I've been sweatin' bullets over this for days. Was afraid to over-charge the system. Now I'm thinkin' about going to Goldendale (Wa.) where it was 106* when I left there last Thurs. Here on the SW Wa. coast I rarely use the a/c unless it's too hot to have the top down. (like never).

Thanks for the replies.

 

If your problem comes back, suspect the heater valve. They can get stuck open and the engin heat will overpower the AC. Symptoms are cold air shortly after startup (cold engine) that turns to warm air once the engine warms up.

You could have been low on refrigerant AND have a leaky heater valve...

 

David.R53 has a good point about the heater valve ... (I have to remember that)

Motor on!