So, I've been encountering a strange problem lately between my clutch and my AC. Seems whenever I start the car (regardless if the engine is cold, hot, or has time to warm up) and turn the AC unit on (not full blast, just one or two levels) the clutch almost immediately tightens. It seems to happen quicker when it's hotter outside, like just after class around noon or after work around six, but has occasionally happened in the mornings and later on in the evenings. Also, if I'm driving and turn off the AC, the clutch will return to its semi-normal pressure within a few minutes.

My commute is under a half hour and isn't horribly stop and go, but it's also not autobahn speeds.

Any ideas on why these two seemingly unrelated systems would cause this problem?

I have an engine light on BUT it's only throwing O2 sensor codes and that light is intermittent. I check it upon its return each time.

Thanks,

 

I still haven't had any luck with this problem - is there any relation or connection between the AC system and the transmission clutch? Additionally, whenever the AC is on, the car doesn't accelerate as swiftly. I know that there is generally a SLIGHT lag, but this is quite noticable.

Any help is appreciated. Thanks

 

Vacuum leak maybe? Not sure if the vacuum system is related to AC system, but it can cause you clutch issues if you are having a vacuum leak.

 

Maybe - We'll have to check that this weekend.

The other thing is that the revs are louder when the AC's running - probably due to higher load on the engine. It's most noticable in 1st and 2nd, though, which I found odd.

Hm.

 

Don't know if this is what you're experiencing, but with the A/C compressor operating there is a definite load on the engine and not only will the clutch engagement feel different, but shifting between gears will also have a different feel as the rpm's drop much faster.

On our modified rotary, with not much torque, there is a vast difference when the compressor is operating. It will take you by surprise when shifting to another gear as the compressor energizes and the RPM's fall rapidly.

 

I'm starting to think that the issue has to do with a failing compressor since sometimes it's fine and sometimes it's not. Ugh. REALLY don't think I can afford that right now.

 

Are you saying that the pedal is noticeably harder to press when this happens?

I can't see an engine issue affecting the pressure required to press the pedal. The clutch is a seperate hydrolic system that's not tied to the engine at all. It should feel the same weather the engine is running or not.

A bad compressor or a vacuum leak could make the engagement feel different because of the lack of low end tourque. The pedal should still feel the same though.

It could be affected by heat if the throwout bearing isn't sliding on its shaft smoothly. That could cause it to bind but it wouldn't come and go with the AC. This is a really interesting problem.

 

It seems like the clutch is harder to depress and the point where the clutch grabs changes, too. Usually, (when the air is off and prior to having this problem), the grab occurs about midway through the return swing of the clutch. When the AC is running, that migrates closer towards the end of the swing. (See below)



I could be in 2nd gear preparing to switch to 3rd and, if I turn off the AC, the problem immediately goes away. Turn it back on, and the revs/noise/tension returns.