Question on gen3 Cooling System

[E36Graduate]

Does anyone know the difference between gen2 and gen3 regarding the cooling system???

I need to crawl under and take a look based on a noise I hear that wasn't present on the gen2 that I am experiencing on our 2012....

Symptoms: Car in park, at idle and normal operating temp (a/c not on). A intermittent cycle occurs very similar to a a/c compressor engaging where the motor revs change a little and I hear a vibration. The vibration and revs go back to normal a few seconds later....this happens continuously and the a/c is not engaging either.

Truck not overheating and draining very well.......it's just something I'm trying to figure out.

I did notice the idler belt pulley in the center of the motor has some play that I'm not sure is normal.....no squreeching noise though? Can visually see play in that pulley when running and the revs change and vibrations start.

My gut tells me this is some type of electric fan cooling system that wasn't present on gen2? Could the vibrations be part of the electric fans kicking on and causing the idles to slightly change for current draw?

I guess I need to get under and take another look!

 

[E36Graduate]

Just got under car.......the a/c compressor is where the vibration is coming from. With the a/c off it still is engaging now and then?? Comes on for a second or two and then off......a/c seems to be working good, even though it is cold out.

The belt and pulley probably should be changed out as there is a little bit of belt noise and I don't like that pulley looking a little wobbly .......

Is the ac compressor supposed to be quiet, or should I expect a little bit of noise....it doesn't sound like a compressor going bad as I have replaced many of them in other cars and know that groaning type sound....

 

[Ripp]

If you have the heat on the a/c compressor cycle that is normal. The only times it won't cycle is when climate controls Are off

 

[montecarlo31]

If you have the heat on the a/c compressor cycle that is normal. The only times it won't cycle is when climate controls Are off

Incorrect. You can command heat and or cool only on the DTAC and disengage the a/c which will stop the A/C compressor from cycling. This will kill the compressor completely. If you command defrost even with heat it will call for the compressor to cycle.

 

[cheapjeep]

In auto or defrost it will cycle that's normal. You shouldn't have any play in an idler though. Sounds to me like the compressor is cycling,putting more stress on the already bad idler causing your vibe. Change out the suspect idler and see where your at.