Hey again. I have a 1998 C280, and the other day I noticed that the AC is not as cold as it should be. Are there some problems that are very common for this model? The AC turns on, just isn't that cold. And sometimes after having the vent on and then turning it off it doesn't come on at all. I was thinking maybe a leak. How difficult is it to replace the compressor? If I can't do it myself, how much should it cost?

Thanks,
Frank Allen

 

thorough check must be done before confiming it's really the compressor.

replacing it needs the car to be lifted... not so difficult after removing the belt. only 4 bolts are holding it.

check the refrigirant pressure by reading from the display. normal is about 12-16 bar with engine running and a/c on.

 

Sometimes they just leak down for some ghostly reason. Mine all of a sudden quit blowing cold air. It seemed sudden, anyway. One day it was cold, the next day it wasn't. I refilled the freon last year and have had no problems since. It costs about $20 (I think) for a refill kit.

I think you can buy a leak detection kit as well. You get a can of freon with dye in it so you see where a leak is. You might want to check into it so you don't replace the compressor unnecessarily.

Replacing the compressor is supposed to be done by a pro, or a person with the necessary equipment. You need to flush the freon from the system, but you can't legally flush it into the air. It's supposed to be contained and put back into the system after repairs are complete.

 

I didn't see sleepwalkers post until after I posted. Do what he says.

BTW, the freon refill kit I bought had a pressure gauge.

 

How long have you owned the car? do you use economy mode if you live in a cold climate in the winter? I was told many years ago, to run the compressor at least once a month in cold weather, to keep it oiled properly as this will cause a compressor failure eventually. My son learned a lesson of a Porsche 944 he had, He never used the AC and one day after 4 years of ownership the compressor started smoking as it siezed up. the mechanic also told him to turn on the compressor in the winter. If you like in a warm climate this does not apply. I have a 99 C280 for almost 5 years and very seldom use the economy feature, as I have see no big difference in gas comsumption with the eco mode as I call it. I agree with sleepwalker and lugnut probably the compressor is going or as lugnut said sometimes the AC stuff just disappears. if You can get some dye AC the system with freon, (it's not real freon as that is banned for decades) with dye you might find a leak. Also, do you have the climate control, if so the ambient temp inside the car has a lot to do with how cold the AC gets especially in winter climates on a mild day. I have seen my go on at 72 degrees in the winter and the outside temp is 40 degrees bu the sun is beating down on the car and the ambient temp sensor tells the system to turn on but at a higher temp.

 

I appreciate the speedy input. I think I will try to refill it first and see if that helps. also is there way to check and add oil to the compressor? How does that work?

 

I don't think they're serviceable. The wiz means that running the AC once a month will keep the seals from drying out, cracking, and causing leaks--self "oiling" if you will.

Your system uses R134 freon/refrigerant. It's easy to find in any discount auto parts store. My system, which I assumed was nearly empty, took two cans.

The next trick is to find the low-pressure valve on your car. There's a high-pressure valve that the kit won't fit without adapters. Don't fit it on this larger valve. The freon can will explode if you do. Hopefully, sleepwalker can tell you where the low-pressure valve is located on your car.

 

Sleepwalker help! Can you tell me where the low pressure valve is?