2003 Yukon..Weird Grinding sound when I turn AC on for the first after a cold start.

[mdmcinti]

Hey Everyone.

Since it is finally starting to get nice out to where I have to turn the AC on when I drive my truck during the day, I have noticed this weird grinding/binding noise when I turn the AC on for the first start of the day. Like what I mean is a cold start in the middle of the day since I have been working from home and have to run to the store from time to time. Anyways, I went to the post office today around 1:30 pm and it was a warm start cold start. After a few seconds of the truck running after I fired it up, I turned the AC on and it made that awful grinding sound and it lasted like 20 seconds. It normally has done it for like a split second and gone away. After looking around online, people are saying the clutch assembly is going bad or the compressor internally is starting to fail? The AC blows ice cold air just fine. Like after I got back from the post office with truck fully warmed up today. I turned the AC off really quick with truck running at warm idle and I turned it back on and no grinding sound whatsoever. Just the typical sound of ac clutch engaging like nothing is wrong. I also have auto climate control fyi. I press the off button and press the auto button to turn it back on. I am weird and I like to start my vehicles with the AC off just because I think it puts wear and tear on the compressor and stresses the starting system and battery. Plus it’s still chilly in the mornings like high 30s to low 40s and if I do have to go to the office, I don’t want the AC blowing when it’s not needed. Any input would be appreciated before it gets even warmer. Thank you.

 

[Doubeleive]

sounds like it's time to think about replacing the compressor, since the issue is consistent you could verify that the noise is indeed the compressor or not by listening closely to the compressor when the ac is turned on (make take a helper). once you have verified I would do it as soon as possible before it completely blows out and potentially contaminates the entire system which cost's a lot more to fix and replace. I have had them sound like a alligator trying to eat a can of nuts and bolts (terrible noise) either that or they start kicking the belt off because they lock up inside or they may sound perfectly fine at idle but when the engine is revved they start sounding like there is a loose nut or bolt banging around inside it.
*** you could also verify it is the compressor by taking the ac belt off and see if the noise goes away.

 

[mdmcinti]

sounds like it's time to think about replacing the compressor, since the issue is consistent you could verify that the noise is indeed the compressor or not by listening closely to the compressor when the ac is turned on (make take a helper). once you have verified I would do it as soon as possible before it completely blows out and potentially contaminates the entire system which cost's a lot more to fix and replace. I have had them sound like a alligator trying to eat a can of nuts and bolts (terrible noise) either that or they start kicking the belt off because they lock up inside or they may sound perfectly fine at idle but when the engine is revved they start sounding like there is a loose nut or bolt banging around inside it.
*** you could also verify it is the compressor by taking the ac belt off and see if the noise goes away.

I see what you mean, but the thing is when driving the compressor does not make any noise and sounds quiet like when I am driving or evening Reving the engine when in park. It is just when it first kicks on after a cold start.

 

[watuzi]

Mine makes that grinding noise all the time when the AC is on, but it still blows cold air. If I wanted to have the compressor replaced, what would be a fair price if I hired a mechanic to do the job? I'm scared of being ripped off and I just recently moved to another city. Hope someone can help me out.

 

[Doubeleive]

I see what you mean, but the thing is when driving the compressor does not make any noise and sounds quiet like when I am driving or evening Reving the engine when in park. It is just when it first kicks on after a cold start.

if it is something new that it wasn't doing before then take it for whatever it is worth, my 03 silverado had a bad transmission for 3 years, it would drive perfect then out of the blue it would not shift out of 1st and sounded like all hell was breaking loose inside, you could shut it off, put in park, start it back up, put it in gear and drive it a thousand miles like nothing was ever wrong would work perfect then out of the blue it would do it again, took 3 years and it finally kicked the bucket. I knew it would die eventually but I got my moneys worth out of it.

 

[Doubeleive]

Mine makes that grinding noise all the time when the AC is on, but it still blows cold air. If I wanted to have the compressor replaced, what would be a fair price if I hired a mechanic to do the job? I'm scared of being ripped off and I just recently moved to another city. Hope someone can help me out.

you can get a compressor for about $160 if you look around, the rest is labor and maybe some refrigerant the mechanic should be able to recover most of the refrigerant before the compressor is removed. I have had mine done a couple times at a small shop that I was a regular customer at so it ran me about $350 all together. its not a lot of labor, they just recover the r12 or whatever in it, disconnect the lines, unbolt it, finagle it out from under the truck (that part is tricky, same for getting the new one back in) limited space (mine was 4wd so a 2wd may be easier to do). then bolt it back up, fill it with the refrigerant and check for leaks. It helps if you match up the new compressor with the old one 100%, sometimes there are small differences such as the relief valve being not present, the new compressor has to match the old one and there are craps tons of compressors the best method is to visually match it up. I would just ask for a estimate to have it done that way there is no surprises most shops will charge extra for parts so ask what the price is if you supply the part also. some won't let you supply the part and some don't care they just want to make money any way. varies from place to place so check around more than 1 place.

 

[OR VietVet]

Sure sounds like the a/c clutch is starting to go but also could be the compressor. Like was said, remove belt and start and remove all doubt. The thing that gets me is that you say it just started when it got warmer outside. That compressor has been cycling on and off when you have the defroster on when it is cold outside. Surprised you didn't hear the noise then. If you replace the compressor and clutch assembly you should also replace the accumulator and the orifice at the same time and flush the system out. If the compressor is failing then it will send bits into the system and get trapped in those 2 components and at the condensor and should be flushed. Plus, replace the belt and tensioner when you do the compressor.

One last thing. You don't have to keep the a/c turned off till after you start the engine. When you turn the key to the crank position there is no power to the a/c clutch and therefore will not be engaged when the engine is cranking. It is designed that way so the starter is not turning the a/c compressor at the same time. If you want to check me on that, just turn on the a/c and then turn the engine off. Then have someone crank the engine and watch the clutch stay disengaged during the cranking sequence and when engine starts the clutch then will engage and spin the compressor.

 

[mdmcinti]

Sure sounds like the a/c clutch is starting to go but also could be the compressor. Like was said, remove belt and start and remove all doubt. The thing that gets me is that you say it just started when it got warmer outside. That compressor has been cycling on and off when you have the defroster on when it is cold outside. Surprised you didn't hear the noise then. If you replace the compressor and clutch assembly you should also replace the accumulator and the orifice at the same time and flush the system out. If the compressor is failing then it will send bits into the system and get trapped in those 2 components and at the condensor and should be flushed. Plus, replace the belt and tensioner when you do the compressor.

One last thing. You don't have to keep the a/c turned off till after you start the engine. When you turn the key to the crank position there is no power to the a/c clutch and therefore will not be engaged when the engine is cranking. It is designed that way so the starter is not turning the a/c compressor at the same time. If you want to check me on that, just turn on the a/c and then turn the engine off. Then have someone crank the engine and watch the clutch stay disengaged during the cranking sequence and when engine starts the clutch then will engage and spin the compressor.

It’s done it before, but it was just worse and longer in duration this time especially since the idle was higher since it was a cold start.

 

[OR VietVet]

Ok, then that makes sense that you were hearing it when the defroster was on and the clutch was cycling.

 

[mdmcinti]

Ok, then that makes sense that you were hearing it when the defroster was on and the clutch was cycling.

So does that mean it’s a bad ac clutch then?