AC Whine?

[tiktok4321]

I get a really loud whine now on my 275000 mile 08 Tahoe. I'm guessing it's the AC compressor bearing. I turn off AC and it's quiet. Speed, auto stop, etc have no effect. Any ideas? Compressors aren't all that expensive... servicing AC is another story.

 

[Joseph Garcia]

Have you confirmed that it is the compressor bearing, and not the tensioner pully bearing?

 

[Blackcar]

Not clutch bearing because it would whine or be noisy when air conditioning is off, Compressor itself may be going bad. Then again you said auto stop doesn't affect so that would point to something not connected to engine like fan motor on hvac blower which would turn off when you turn off air conditioning.

 

[swathdiver]

Mine started making noise intermittently in 2018 and makes noise all the time now. The Sierra started making the exact same noise last year and just about every Tahoe, Yukon and Escalade I hear around me makes the same noise too.

I contemplated changing out the clutch with a new one but will probably change out the whole compressor one day. It's not high on my list of priorities... until it blows up down here in Florida! Maybe I'll put it on the list during the fall availability for repairs and maintenance.

 

[j91z28d1]

you have electric ac compressors. they run off 300v battery. last I looked at gm parts direct it's about 1700$. cleaning a system out after a belt driven compressor blows up in a nightmare and you can't flush stuff these days, so mainly you just replace everything. depending on the car, sometimes you gotta drop the dash out to get to the evaporator over a few 100$ compressor. for these I don't know if it's worth throwing that kinda money at it till it goes out or not.

275k miles seems like it lasted a while thou. don't think I've seen any gm belt driven comp go that far. how's the hybrid battery doing at 275k?

 

[tiktok4321]

Yeah - I know it's an electric drive compressor, but I have read that it mounts similar and in the same place as the engine driven pump. I can handle the whine. Truck is on its last legs, but it ain't gonna be cheap to replace.

275k miles seems like it lasted a while thou. don't think I've seen any gm belt driven comp go that far. how's the hybrid battery doing at 275k?

So - I had to replace the engine about 4-5 years ago. I replaced the Hybrid battery just before that with a Greenbean. Was initially happy with them, but when the replacement started faltering, they refused to replace it under the tiered warranty because the Tahoe doesn't have battery life messages on the info screen or check engine light. That was when it was $1500 to replace. Now it costs over $3k. The only real symptom I have is that it lunges when it's transitions to/from auto stop. It totally went away for about two years after I got the battery. Now, I shift in and out of M if I'm city driving. Wife only drives it in M (getting a whopping 13mpg). I drive in "D" when on the highway. I still get around 20 mph when i baby it.

 

[j91z28d1]

Yeah - I know it's an electric drive compressor, but I have read that it mounts similar and in the same place as the engine driven pump. I can handle the whine. Truck is on its last legs, but it ain't gonna be cheap to replace.



So - I had to replace the engine about 4-5 years ago. I replaced the Hybrid battery just before that with a Greenbean. Was initially happy with them, but when the replacement started faltering, they refused to replace it under the tiered warranty because the Tahoe doesn't have battery life messages on the info screen or check engine light. That was when it was $1500 to replace. Now it costs over $3k. The only real symptom I have is that it lunges when it's transitions to/from auto stop. It totally went away for about two years after I got the battery. Now, I shift in and out of M if I'm city driving. Wife only drives it in M (getting a whopping 13mpg). I drive in "D" when on the highway. I still get around 20 mph when i baby it.

I may have your post mixed up with another above, i got the feeling you or someone thought it was a normal cheap belt driven ac compressor. sorry about that.


I'm a bit surprised by the engine needing replaced, I wonder if it was the cyl deactivation lifter issue or something else. I was kinda expecting the ls based engine to outlast the truck haha. battery seems to be the weak part, shame most of the aftermarket ones just use used packs from other cars. only picked mine up a bit ago, it's got 130k on the oem pack, I knew it was going to start acting up soon when I got it, and factored in replacing it. I had the scanner on it looking at cell voltage and the min and max. under a load max was holding 15v but min dropped to 12v very quickly with dual ac in max and the engine started instantly. I had one of the lithium packs in the cart and almost hit buy, but since it hasn't done any of the bucking yet, I held off. then we had a 100deg day and after parked in the sun ac on max engine stopped at a red light for a min or 2 it bucked on take off, not bad, but enough. went back to hit buy and I missed it, they sold out again. shame too, like everyone they say supply issues so no eta on next shipment. it hasn't done it again, but only a matter of time.

oh, I have the 4cyl mode shut off with hptuners, so hopefully I get 250k out of it like you have.

 

[tiktok4321]

I may have your post mixed up with another above, i got the feeling you or someone thought it was a normal cheap belt driven ac compressor. sorry about that.


I'm a bit surprised by the engine needing replaced, I wonder if it was the cyl deactivation lifter issue or something else. I was kinda expecting the ls based engine to outlast the truck haha. battery seems to be the weak part, shame most of the aftermarket ones just use used packs from other cars. only picked mine up a bit ago, it's got 130k on the oem pack, I knew it was going to start acting up soon when I got it, and factored in replacing it. I had the scanner on it looking at cell voltage and the min and max. under a load max was holding 15v but min dropped to 12v very quickly with dual ac in max and the engine started instantly. I had one of the lithium packs in the cart and almost hit buy, but since it hasn't done any of the bucking yet, I held off. then we had a 100deg day and after parked in the sun ac on max engine stopped at a red light for a min or 2 it bucked on take off, not bad, but enough. went back to hit buy and I missed it, they sold out again. shame too, like everyone they say supply issues so no eta on next shipment. it hasn't done it again, but only a matter of time.

oh, I have the 4cyl mode shut off with hptuners, so hopefully I get 250k out of it like you have.

That's exactly what it was. The eco-mode lifters failed in Cyl 8. They tried to do a top overhaul but it failed about three months later. It is an aluminum LS so it's not quite as robust as the steel case V8s. Does AutoStop work when you turn off 4cyl mode with hptuners? Honestly, I'd rather keep that - it's the only thing that lets me get a reasonable MPG - especially when my wife drives it in M4 all the time.

 

[j91z28d1]

yeah, everything works like normal, mine stops and starts drives on electric only up to about 20mph if i try to, just doesn't activate 4cyl mode. other than that everything is the same. I honestly saw no difference in mileage, there's a timer on 4cyl mode labeled oil foaming, I don't remember the max time it allowed it to stay on but it's in seconds. I did it a few days after I got it in the middle of a road trip, didn't see any mileage different up there, maybe some around town. there's also a guy that makes a manual block off plug that once you turn off the electronic side you can plug the oil passage way under the oil pressure sensor going to it to make double sure no pressure builds up and deactivates the lifters. but you can't do that till it's done of the tune side first. I've got the plug but haven't done it yet.

it's 2 credits to unlock the ecm with hp, which come with 6 preloaded, at least did years ago when I bought mine and then it's just a drop down box, it's labeled backwards for some reason, but they say it's how gm commented it in the code, so they left it. change it to enable and it disabled it. I already had it for my c6, so didn't cost me anything. I'm sure any tuner can do it for you, or they seem to sell well used with the 4 credits you'd have left. there's not a ton you can tune on these trucks besides that, you can cal the speedo for different tires, adjust the wot a/f target but no ve table for tuning over all a/f. which I though was odd, as I've seen one post somewhere of a guy doing a full air intake and picking up a mpg. if you had the ve table access you could do an intake and without 4cyl mode hack off the big extra resonator they added to kill the 4cyl drone and pick up another mpg probably.

no hybrid stuff at all, but I wanted to avoid the lifters issues, as I tend to keep stuff and don't really sell cars very often, this should be a around a long time. engine looks spotless inside from what I can see what a bore scope and I changed tranny fluid and filters the other day and it looked surprisingly clean in there. the tranny setup is really the only thing that worries me long term. hopefully it hangs in there.

 

[dnt1010]

I am now at 261k on a 2009 and it is running well. It has its small issues but it sure makes for a great Beater Ride. i have not noticed any extra whine on the AC compressor but all these hybrids seem to make some weird noises anyway so i tend to not listen (just ignore it) unless it is really loud Hahah. Very pleased all around with my $6,600.00 purchase about 4 years ago at 195k