A/C compressor not turning when the motor is running.

Currently the serpentine belt on my 2009 Tacoma (4.0 Liter) just runs over the a/c compressor pulley not turning the compressor. Could it be the compressor has leaked PAG oil & 134 and is frozen or is the compressor just shot? (Truck has 146k miles)

 

Is the A/C on

 

Could be just a failed AC clutch

This might help. https://www.tacomaworld.com/threads/ac-clutch-failure-how-to-fix-blinking-light-squealing.448009/

If the compressor were seized it would cause the belt to burn up. Fast.

 

Welcome to Tacoma World!

My first question would be, did you have the AC or defrost on?

The compressor has a clutch that allows it to be bypassed when the system is not engaged.

 

Yes the a/c is turned on and the serpintine belt is connected to all pulleys but not turning the a/c pulley. Not an a/c clutch problem I don't think as nothing on the compressor is turning and the belt is not burning up.

 

If there is not a burning smell, or much noise emanating from the area then I'm going to presume the compressor is ok. I'll also note that I have limited experience with a seized compressor.

While the engine is running, can you cycle the ac or defrost from off to engaged? There should be noticeable noises, and subsequent cold air from the vents.

(Edit- typo)

 

Can you remove the belt and use a socket to the center nut and try to turn it by hand to see if the a/c clutch/compressor is seized? It sure seems like that's the case.

 

I just went out to verify on my truck, I started the engine and engaged "max Ac".

The system will engage with a noticeable click noise and I can watch the internal part of the pulley begin to spin. Does this occur when you follow that sequence of events?

 

The clutch pulley turns by default all the time. If not (frozen) the belt will scream and burn off.

When powered up the clutch engages and lets the belt spin the compressor.

Did you look at the link I provided?

Clearly I can't say from here on the couch that's what it is, but its not uncommon either.

 

If center part of the pulley starts turning, the clutch kicked in & the compressor is turning

 

If you are low on refrigerant, the clutch will not engage and the AC pump will not turn.

Did you notice last season if the AC was not as cold as it should be? If yes, you have an R134 leak. Start simple, look for a leaky condenser.

 

Wait a minute, in post #5 you said the a/c was on but the compressor was not turning. If the center off the compressor pulley is turning, the compressor is turning. If the center of the compressor pulley is not turning, the compressor is not.

 

Now it just sounds like you may be low on refrigerant. Put some gauges on to verify.

 

I got it, it's April fool. He never even said his A/C wasn't cooling, just that the pulley wasn't turning. Looks like we've been fooled

 

Just to clarify to all, this was not an April fool’s joke. I can put the A/C on and there is no click/noise of the magnetic clutch being engaged on the compressor. The compressor does not turn with the motor running, the belt just slips around the pulley and is not burning as you would think. I haven’t had a chance to put a wrench on the compressor bolt that holds the clutch to see if the compressor is frozen but will keep you posted.

 

So, can you answer me, when was the last time you can remember cold air coming out the vents?

 

Look closer. The clutch is turning just as if the AC is off. Turn on the AC and nothing happens, no click, no screeching belt? Then it is not a frozen compressor, the clutch is not getting 12 volts to make it engage.

Do you have a volt meter?
Edit to add: As others have posted, check the freon level first.

 

Put a white paint dot on the edge of the pulley the belt is around.

If it doesn't move when the truck is running you have the most durable belt known to man.

 

Also known as a Thanksgiving Belt.

 

OK, Now I see. If the compressor clutch doesn't engage, it does look like the pulley isn't turning. Mostly what you see is the main, center, compressor hub that is not turning. The actual pulley is just a small, maybe 1/8" ring part just under the belt that turns anytime the eng. is running. He's not seeing the little ring that is he pulley. Yep, till you hear the click of the clutch engage, the center hub of the compressor will never turn. If freon is, too, lo, the pressure switch won't let the clutch engage. I'd say Lo freon is the most common problem causing clutch not engage. Sorry I got confused.