Ac compressor woes

Hey all, for a while now I've noticed a ticking sound when I turn on the ac button. I'm pretty sure it's coming from my ac compressor. The sound is also happening during acceleration (louder when the ac is on) sounds like an exhaust leak. I was watching the compressor run while I had the ac on and noticed a part, not sure of the name that spins and stops. Is this part pictured below, circled in red, supposed to spin continously if the ac is on?


check for pictures on the internet

 

I’m no expert on AC and have never installed one or taken one apart on our trucks but there will probably come a time down the road.

I believe that piece is a clutch wheel that engages and disengages at the ECM discretion depending on what mode you have set.

 

Completely normal. As mentioned above that is the AC clutch. When it engages, this turns the compressor on. What your seeing is the compressor clutch cycling.

 

How can I diagnose what the clicking sound is, besides replacing the ac compressor?

 

Are you sure it is coming from the AC compressor/clutch?

 

No but the clicking sound happens as soon as I hit the ac button.

 

It could be as simple as a belt noise that you are hearing. Usually this comes in the form of a squeal due to the belt slipping on drive pulley(s). When you turn on the AC, the belt is put under more load/stress. My belt makes a bit of a ticking noise as well (plan to replace) soon. I would pull the belt and inspect it and the pulley on the compressor. Simple and quick task to eliminate.

 

Belt seemed fine not sure about the ac pulley. I'll take a closer look.

 

What frequency is this "clicking"? That is, how much time between clicks? Several clicks per second, 1 second between clicks, 5 seconds, what?

The clicking associated with normal AC cycling results from the electromagnetic clutch connecting the compressor shaft to the drive pulley. The time between normal cycles, i.e. clicks and idle speed changes, should last many seconds, maybe minutes between clicks, and is a function of ambient temperature and AC load.

Rapid clicking, say one or multiple times per second, implies a mechanical problem in the clutch mechanism or drive system. In that case, if the clicking is not the belt, then you're probably looking at compressor/clutch replacement to eliminate the click. I would turn up the radio until the AC quit working.

 

Perfectly normal. The clutch is an electromagnet so when you hit the A/C button the clutch (circled in red in the above pic) gets pulled in and results in that clicking sound.

Edit: ^^^ JL said it better!

 

The clicking is around 3 or 4 per second. When I accelerate the frequency goes up and is louder. The clicking is also present during acceleration when the ac is off but becomes noticeably louder as soon as I hit the ac button.

 

Exhaust manifolds?
What year is your truck

 

2002

 

That's what I was thinking.

@theSteels it might be worth reading this thread.

https://www.tundras.com/threads/diy-steering-shaft-seal.48664/

 

Yeah when it was stated the noise happens with and without the ac on, that kinda rules out the AC

not sure if OP mentioned if it’s way louder of a tick in the cold mornings?

 

It may not be the AC but the clicks definitely become noticeably louder when the AC is activated. The clicks are louder and a higher frequency during acceleration when the the AC is on. Other times when the AC is off there is no noticeable clicking sound during acceleration.

 

Thanks reading now

While it could be this, I don't think it explains the noise difference heard when I turn on the ac with the hood open standing by the radiator (someone inside the truck activates the button).

 

Frequency says it's a mechanical problem, maybe a bearing, in one of the accessories (AC compressor, alternator, PS pump, etc.), or an idler pulley, driven by the serpentine belt. The fact that the noise gets louder when the AC is engaged doesn't necessarily mean it's the AC compressor. The noise is increasing when the AC compressor is engaged because the load on the serpentine belt, bearings and idler is increased, which could make the noise louder.

Localize the noise with a mechanics stethoscope. If it's an exhaust manifold leak, that should become clear quickly. I would start with the alternator; that's where my instinct is now headed.

 

I’d check play/ replace the tensioner pulley and idler pulley before the alt

 

I forgot to mention that I need to replace the the fan bracket as that bearing is worn out. That might be my problem, sorry if I totally went backwards there and didn't mention it in the 1st post. I should've done it when with the timing belt off but couldn't wait for the part.

 

Totally deserved, that bracket issue totally evaded me, I hadn't made the connection that turning on the ac could put stress on a different component.

 

Just kidding. No problem.

It was a good "work-out" for the crew, and we got instant feedback, unlike most attempts to help.

 

Yeah I'm def a noob shade tree mechanic. I'll report back here when replaced

 

I should be getting the fan bracket this week, in case this doesn't fix my ticking problem, what else should I look at? I forgot to mention that the ticking sound only gets louder when the car is put into drive or reverse. If the car is on park and I turn on the AC it starts the clicking sound.

 

Hey all, I replaced the bracket and I'm still getting the ticking sound. I'm almost sure it's coming from the AC pulley. Can this pulley be replaced or do I need to swap out the whole unit? Any ideas on how to isolate or confirm it's this pulley?

 

There is no replaceable "AC pulley". The AC compressor drive pulley is an integral part of the magnetic clutch assembly. Magnetic clutches can be noisy when the compressor cycles on/off, but once engaged there should be no noise from the clutch/drive pulley.

Unless the clicking noise is continuous when the compressor is turning, i.e. when that front part of the clutch is rotating with the pulley, I would not worry about the noise. I would assume it's normal clutch noise, and run it until the AC quit working.

But...If you have continuous clicking only when the compressor is turning, that may indicate a failing bearing in the compressor. (Eventually, I would expect a lot more noise than "clicking"). In that case, it won't be long before the AC does stop working. Unfortunately, if the compressor "locks up", it may break or throw off your serpentine belt, and leave you stranded on the side of the road.

 

I think you are low on R134. It is clicking on and off because the low pressure switch is
cutting power to the clutch. How cold is the vent temperature?

 

The sound is always there. It becomes louder and is synchronous with higher acceleration. If I hit the pedal the ticking/clicking sound gets louder and goes up in rpm too. If it I put it in neutral and hit the pedal the ticking also goes up in rpm. I haven't used a stethoscope but I had my ear close to the AC compressor and I'm almost sure it's coming from that spot.

 

You can be sure, or you can throw parts at it until you find it.

A mechanic stethoscope is not an expensive tool.

$20 Lisle 52500 Mechanic's Stethoscope

https://www.amazon.com/Lisle-52750-...7555282&sprefix=mechanics,aps,297&sr=8-3&th=1