Is there such thing as out of balance (engine, AC fan, etc.) that cause rough idle?

[smokey_mountain]

I think vibration was less during the cold season with AC off. Now that heat is here it is prominent. Is there a way to test the AC load and clutch? Could electrical AC fans cause vibrations if they are out of balance?

Does the vibration change with the ac on vs off? I have ridden in some older and one newer vehicle (2016 Chrysler 200) that the ac compressor clutch is going out or the load is to much for the engine to handle at idle so they begin to vibrate. The Chrysler was really bad. It didn't matter what gear the car was in either.

 

[Dantheman1540]

I think vibration was less during the cold season with AC off. Now that heat is here it is prominent. Is there a way to test the AC load and clutch? Could electrical AC fans cause vibrations if they are out of balance?

Likely it wouldn't be the AC fan problem but the load the compressor puts on the accessory drive system. Possibly the compressor is out of balance or the clutch sticks I'm really not really sure what exactly the cause is but in the past I have replaced compressor clutches which have solved the problem. Not saying for sure thats the issue you but theres a chance.

 

[smokey_mountain]

Thanks. Is there a test of any kind to check if compressor or its clutch is at fault?

Likely it wouldn't be the AC fan problem but the load the compressor puts on the accessory drive system. Possibly the compressor is out of balance or the clutch sticks I'm really not really sure what exactly the cause is but in the past I have replaced compressor clutches which have solved the problem. Not saying for sure thats the issue you but theres a chance.

 

[OR VietVet]

A sight check and "laying on of the hands" feel of the compressor should tell you what you want to know. You could remove the a/c belt and run the engine to see if the problem goes away.

 

[Dantheman1540]

I'm no GM master tech but I would create the rough idle condition and then while looking at the compressor have someone shut the AC off. Usually there is a button that turns just the compressor off but still allows the fans to blow. See if there is any change in the vibration and if so see if you can visibly tell what was wobbling, loose or messed up in some way.

 

[Dantheman1540]

A sight check and "laying on of the hands" feel of the compressor should tell you what you want to know. You could remove the a/c belt and run the engine to see if the problem goes away.

Great advice.
Removing the belt and seeing is probably the most definitive way to exclude the compressor in the scenario.

 

[smokey_mountain]

Got it, will do today and report back if I find anything.

 

[smokey_mountain]

I have done a bit more highway driving and then ran the engine at the traffic light stop in D with AC off (did not take the belt off, just turned off the AC) and the vibrations/flutter was still there, maybe to a lesser degree but certainly did not stop when I turned AC off.
Harmonic balancer might be the ticket or as suggested it is fuel system somehow.

 

[Dantheman1540]

Since the level of vibration changed slightly with the AC off which is run of the belt drive system I think we might be getting to the right spot. I would take the belt off completely and start it for just a minute or so. Water pump obviously won't be running so you don't want to run it long enough for it to get hot. However if the vibrations change more then the only accessory item that could cause it would be the harmonic ballancer. If it was a fuel pump or injector issue I would assume you would see a code for missfire or O2 sensors reading lean.

 

[smokey_mountain]

I am new to GM V8s is there a tutorial for Gen V belt removal? Thank you.

Since the level of vibration changed slightly with the AC off which is run of the belt drive system I think we might be getting to the right spot. I would take the belt off completely and start it for just a minute or so. Water pump obviously won't be running so you don't want to run it long enough for it to get hot. However if the vibrations change more then the only accessory item that could cause it would be the harmonic ballancer. If it was a fuel pump or injector issue I would assume you would see a code for missfire or O2 sensors reading lean.