well for about 2 years now, every time I turn on the heater or a/c, there is a loud and violent throb that comes from the engine compartment. its so bad that everyone within 100 feet will stop and stare. it used to not happen all the time, but now everytime i have the heater on it does it. im sure its because of the a/c pulley, maybe its bent or something and when it wobbles it makes a horrible sound. and now when i start it up the belts start squealing like crazy. could these possibly be related? the only thing i dont get is it happens when the heater is on too, so it couldnt be the a/c pump, at least i dont think. any suggestions? by the way, its a 97 4runner 3.4. and im sure the belts are old and need to be replaced, but i dont think that will fix the throb from the heater and a/c

 

Riddle me this??? Is it with the heater or the A/C. When you turn the heat on make sure the defrost is not on, the A/C should not run if the defrost is off.

 

yup definitely a/c. makes no noise with just straight heater

 

Could it be just the belt??? Maybe try to tighten it a bit or spay a bit of belt dressing on it.

 

you think just the belt would make the whole a/c pulley wobble like that?

 

Na, sorry missed that.

If the pulley is a wobblin time to replace. I think you can take it apart and swap the pulley but if it's been doin this for 2 years the pump maybe shot. The wobble may have messed up the shaft as well.

 

ok. well i guess ill take it in tomorrow. thanks for your help

 

Hit up a pick an pull then all you'll need to do is get it recharged.

 

Might also check the A/C idler pulley as well as the pully on the compressor. Remove belt and give both a spin and feel for play in both pulleys.

 

An a/c compressor clutch pulley can go bad and when you turn it on, instead of turning with the belt it will lock up causing the belt to squeel because the a/c pully isn`t turning. the clutch pulley can be replaced.