bbrain

i read this forum often, but i just registered recently

i have an '03 c240 and my AC blows cold only when i am driving and is cooler when i am not facing the sun.

the dealer said it was my freon my last checkup before my warranty was out =/

but that was during the fall, and now it is summer and i am dying.

do you think it is the condenser fan or the compressor?
or any other ideas?

thanks alot for any help

Defiant

I'd go with the dealer's guess of it being your refrigerant level. Doesn't a '94 use 134a?

bbrain

mine is a 2003-2004 model

i thought it was that too, but when i am driving on the freeway it blows nice and cold for even a trip that lasts hours?

confuses me =/

bbrain

bump for summer coming back into play, and i sold my civic so this is now my only mode of transportation.

same deal, AC works while car is driving without stops (such as being on the freeway)
also realised in the shade the ac works better ..

fyi my stepper motor is out as well, but even last year when it was working i felt the heat

any suggestions besides asking dealer to bend me over?.. im melting

thanks in advance

dnlow

I would think it is a weak or dead cooling fan. Since the air blows cold when you are moving, it seems like the AC compressor is working. There is a relay that turns up the fan speed, when needed, so that may not be working also.

Also. was the refrigerant level corrected? This would cause problems, too.

bbrain

thanks, the refrigerant level was corrected. do you know what the relay is called? i will have that checked this week.
and there is only one fan correct?

dnlow

the c230 only has one. I am not sure about the c240. I do not know what the relay is called , but since the fan is multi-speed I am assuming there is one. If I had an electrical schematic for your car I could figure it out right away. Sorry I can not be of more help.

All I can say is that I am almost sure there is some issue with the fan. The refrigerant needs air moving across it to remove the heat that is in the refrigerant. No fan, no air movement across AC coils, no cooling.

Good luck.

gallaghp2

My C230 has a leak, so I lose about 40% of the freon. I am taking mine to a shop tomorrow to check if the added dye has helped at all. How long does that dye typically last for?

Right now the AC is working, as I had the EC Rest button reset and a full recharge, but the shop did not find the leak - said they had to put the dye in. I hope that helps~!

I also have the stepper issue for the left foot well.

danev6972

Did you get it fixed bbrain? I have the same problem too.
It takes forever to cool even after a ref refill.

bbrain

getting it diagnosed tomorrow morning at the stealer.. been driving around my civic i got back from a non paying buyer on the hotter days. heh

i will let you know what they say, easy way to tell it is the fan.. is if your car does not sound like an airplane anymore

chokaay

I just had my 2002 C240 AC System refilled with Freon a month ago. Symptoms of low freon included: AC blowing hot (or not as cold as it should be) air all the time, and hearing the compressor (or some kind of pump) keep trying to initiate all the time. After the refill, AC is blowing ice-cold air, and the compressor/pump sound went away.

According to my SA, it's "normal" for Freon to need to be refilled after 7 years, and this was a "maintainence item"... but it is NOT checked nor done on any Service A or B. It's apparently only checked/done if the owner complains. IMO if it's considered a "maintainence item", then it should be routinely checked (either at Service A or B)... why the heck wouldn't it be checked?!?

Glyn M Ruck

These cars have a refrigerant pressure sensor. If all the 134a is gone the aircon will refuse to switch on. I you still have a partial refrigerant charge it can give the symptoms you describe.

Glyn M Ruck

See this:

https://mbworld.org/forums/c-class-w...on-always.html

Are you absolutely sure you don't have a refrigerant leak. You have to sort that out first! - or you can't diagnose anything else properly.

bbrain

my SA informed me that my fan was only blowing at 20% due to a faulty regulator, went on to inform me that the fan assembly only comes as a whole, so i agreed to replace it (a $500 part) . after two hours i checked in, they installed the new fan assembly only to get my fan up to 40%, he continued on to say the compressor was only working at 70% as well (irrelevant imo) so my car will remain with them until monday, hopefully they find out why else the fan would not be going up to normal levels.

only upside is i get a c350 for 4 days.

Glyn M Ruck

The idiots simply can't diagnose. I'll bet there was nothing wrong with your fan.

LILBENZ230

Ugh part swappers. It's different when they throw parts at it while it's under warranty but when it is on your dime I'd be miffed.

bbrain

ya, it is troublesome when you are in desperation and they seem like they know know what they are talking about.. i do hope they solve whatever it is. any way i can get them to fix the true problem for free if the fan was not the issue? anyone ever have luck with that?

bbrain

ok, the SA called me and informed me that the fans are running at 70% and the compressor is running at 70% giving about 53° when it should be at least 40°.. the foreman says that the fans are listening to the compressor and will only run up to the 70%, but they also say the fans just randomly cut out.. they are saying that if they replace the compressor and expansion valve (mucho dinero) everything 'should' work at 100%

thoughts? any other reasons the aux fans will not be running at 100% ?

thanks in advnace

Glyn M Ruck

I'm no aircon specialist but there is some logic to what they are saying if the system is fully gassed - I don't know about why the expansion valve needs replacing but if the compressor is not up to snuff then you will be dissipating less heat across the condensor so the fans do not require to run flat out & are sensing correctly.

What mileage has the vehicle done? This is a very rough guide because aircons/ compressors that are used regularly usually last longer than those that are not.

bbrain

the mileage is 165k, and the aircon was used regularly.

i just do not get how the fans were running at 20% then the new ones were running at 70%, but they say it may not be the fans

thanks for your help

Glyn M Ruck

Have they replaced the fans??? - I doubt there is anything wrong with the fans. At that mileage a compressor replacement is reasonable - it's not a long way for the engine but it is for the compressor.

bbrain

yes they replaced the fans, that was the first thing they did, they did not call me today, so i will call tomorrow. just dreading the bill to replace the compressor

skittles

i have the same problem with bbrain. cold when running and tends to heat up when standing still.. also sometimes (i always use the auto button) the ac turns off by itself. i press auto again to turn it on but after 10 secs it shuts off again. but sometimes just stays on. i thought it was a temp thing like the car feels like its cold enough thats why it turns off.. is this an issue i should be concerned with? or is it normal?

Glyn M Ruck

Yes - compressor is darn expensive. I would query the fan/fans. They either work or they don't.

Glyn M Ruck

The most common cause of the AC shutting itself down is low gas pressure. On auto it should start with the fan howling until the temp in the car is reduced & then it should continue at low fan speed. What mileage has your car done?