My 1999 C230 was driven through a lot of water recently. The MAF was replaced as well as the the cabin filter. Apparently, water went through the air ducts and was expelled into the interior of the car. The fan would not operate. The dealer changed the MAF, changed the oil, cabin filter, etc. but didn't check the AC. Took the car back and they recharged it. Went to 41 degrees but a week later no AC. I'm taking it back in on Monday.

I need some help because the insurance company doesn't want to pay to fix the AC. It worked perfectly until this water incident. Did the water allow pressure to build up in the system and cause a refrigerant leak? Any theories? Thanks.

most likely refrigerant leak. check all a/c hoses if you see an refrigerant oil build up somewhere within the lines. if you find one thats the culprit
good luck

That's what it was. There was a leak in the condensor. Unfortunately, the dealer could not say that the leak was caused by driving it though the water. It seems to me that somehow the water caused pressure to build up in the system and that caused the leak. If anyone has any theories how driving through high water could cause a refrigerant leak I would appreciate it. It would save me $1,300.

The condenser is in front of the radiator. Any debris going through the grille of the car will hit the condenser first. Where was the leak? Was it in a location consistent with debris impacting the condenser?

Brett

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1997 S600 sedan

Good point. However, the dealer told me the leak was in the rear of the condensor, the side facing the radiator.

the condenser gets very hot when the AC is on because the heat in the cabin is transferred to the refrigerant and the refrigerant dissipates the heat in the condenser.
The physical structure of the condenser is very vulnerable, you have so many corners and weldings and weak corners of that sort where the little tubes going across connect to the main column that brings in the pressurized refrigerant.
Metals show the most expansion and contraction due to temperature changes, the condenser is made of metal (aluminum i think???) so when it's hot it is in the expanded state.
What I think happened is that the water which was cold hit the condenser when it was hot and the "heat shock" caused it to crack due to "rapid" and "uneven" contraction of the different parts I say uneven because water did not cool down the condenser in a uniform manner but rather a random pattern of water splashing on the condenser. The water caused a heat shock to the condenser and the non uniform cooling caused some parts to contract while some parts are still hot in their expanded state. Like a tooth, eating ice cream after a hot cup of tea is not such a good idea and causes a crack in your tooth.
see if they'll buy this from you. try to get a hold of the old condenser and hope that there is a crack no matter how small where it looks like some one pulled on both sides of the crack to sort of rip apart the condenser. (it doesn't have to exactly look like that but that's how I'm picturing it in my head) I would expect the leak to be in a corner, corners are the weakest spots.

Sounds like the water may have put pressure on trash that was already between the radiator and the condenser...May have only been a matter of time before you sprung a leak anyways...

My a/c was working intermittently on my '91 300d. They finally found the dampner and idler pully were a bit warped, due to be changed, and they recommended the serpentine belt be changed. They figured what might be happening, is that the belt, even though it was not loose to the eye, might be skipping just a bit. They said if it slips just a tiiiiiiny bit, it will shut the a/c off. I had the repairs done, and a/c works fine now.

They also said to make sure the belly pan is on (the thing at the bottom of the engine to catch fluids). They said it keeps water off all the electrical stuff, as well as keeps road noises down.

Good luck.

I do agree with the water pressure against the condenser. that is more likely what happened as opposed to the thermal shock. I still believe that sudden changes in temperature dramatically weakens joints and structures, but the huge amount of water pressing against the condenser is probably a better explaination in this situation.