A/C Belt Breakage

jsmca22 · July 31, 2005

I have a 2000 Z-71 that keeps snapping A/C belts, I have replaced 7 in the past 6 months. The original lasted 3.5 years, since then it has been a nightmare. The AC Delco belt seems to last the longest. The snapping occurs at various time, hiway speed, idle, I have tried turning the A/C off after each trip and not starting with the A/C on but it doesn't seem to matter. What can be causing these belts to snap so often??

jsmca22 · August 9, 2005

Sold, $13500, feel sorry for the new owner, I just bought a Dodge diesel, pretty nice......................

Seattleritch · May 6, 2006

I have the same problem with my 2003 Sierra.

2003 is a known issue, but he's got a 2000. Here's the TSB. Perhaps applying it to the 2000 would help. Don't really know...

So here's a question I probably don't want the answer to. I have an 02 Suburban I bought used 2 years ago. This is the exact problem I have been having since I bought it. Is there any way to get Chevy to make it right, or am I out what sounds like a couple grand for repairs?

Tucson_02Silverado · May 10, 2006

It's moot now...but as GMtech posted, it's was the tensioner...too loose.

You should not be able to move the tensioner by hand enough to install/uninstall the AC nor the main belt.

OR...the "wheel" on the tensioner was binding or frozen and heated/wore through the belt

mmmikkke · July 31, 2005

I have a 2000 Z-71 that keeps snapping A/C belts, I have replaced 7 in the past 6 months. The original lasted 3.5 years, since then it has been a nightmare. The AC Delco belt seems to last the longest. The snapping occurs at various time, hiway speed, idle, I have tried turning the A/C off after each trip and not starting with the A/C on but it doesn't seem to matter. What can be causing these belts to snap so often??

<{POST_SNAPBACK}>

I'd suspect either a misalignment or an accessory that's failing (e.g. your a/c compressor). Another possible cause is excessive belt tension...make sure your tensioner is moving freely (while no belt is on it).

mmmikkke · August 5, 2005

Could this be causing the belt to snap, they are not melting apart from a compressor or clutch stopping, they appear to be snapping in two from a sudden jerk or something. Is there a way to check the amount of tension the belt should have on it? or is there a way to check the amount of tention the tension pully should be applying?

<{POST_SNAPBACK}>

I'd check to see if the belt is threaded on the correct side of all the pulleys. If it's on the wrong side of one or more pulleys, it might explain why it's so easy to push the tensioner down. Tensioners usually have a hole or boss to accept a pry bar or a 1/2" drive breaker bar. That's how much force they usually need to move out of the way of the belt.

Trotorx2 · August 5, 2005

A friend of mine has the same problem with his 2000 GMC ECLB 4.8 2wd. He finally went and got the next larger belt and hasn't had any problems since. I don't know where or what P/N belt he got but it is working fine.

jsmca22 · August 5, 2005

Thanks to everyone for their insight, I think I will sell the dang thing let someone else deal with it, I'm tired of sinking $$ into something that can't be fixed without trying this or trying that, it ain't suppose to be rocket science to be able to fix a Chevy!!!

GM-Tech · July 31, 2005

I want to say it sounds like a compressor locking up briefly, but I would think after six months, it should have failed totally by now or at least cause more frequent problems.

jsmca22 · July 31, 2005

I was told by a mechanic that GM is aware of this but has not posted anything on it because they fear liablilty would cost them. I was told the compressor is probable the problem, my only thing is the A/C works fine other that snapping a belt. The tension pully is free and movement is easy by hand. The last belt I personally changed on Friday this past week and I was able to use my hand to pull the tension pully down to get the new belt on. If it is the compressor, why and what would cause it to lock up even if it just for a second or so??

mmmikkke · July 31, 2005

I was told by a mechanic that GM is aware of this but has not posted anything on it because they fear liablilty would cost them. I was told the compressor is probable the problem, my only thing is the A/C works fine other that snapping a belt. The tension pully is free and movement is easy by hand. The last belt I personally changed on Friday this past week and I was able to use my hand to pull the tension pully down to get the new belt on. If it is the compressor, why and what would cause it to lock up even if it just for a second or so??

<{POST_SNAPBACK}>

I think...I think the compressor is a 3-piston unit. I think it's a lot like a 2-stroke engine, the crankcase has the low pressure refrigerant/lubricant, and 3 pistons send it to the high-pressure side of the system through reed valves.

I think that the rings can wear out, eventually reducing compressor efficiency, and increasing friction in the 3 cylinder walls. That puts additional strain on the compressor crankshaft, and so it starts to wear out also. You can usually "hear" a compressor failing, as it develops a knock.

Depending on where it comes to rest, the failing compressor probably takes a lot more torque to get moving. So maybe 1 time out of 5, when the compressor clutch engages, your belt get stressed beyond its design strength, and it starts to fail also.

That's a fair bit of conjecture, though. Anybody know for sure?

jsmca22 · July 31, 2005

If all you say is accurate, wouldn't I be loosing cooling somewhere? The unit cools just fine and I haven't noticed any knocking of any kind. The unit has never been serviced as far as needing a charge or anything, would you think I might try to discharge the unit and re-charge it with new coolant and oil? I'm at a complete loss here, I just know I am tired of changing belts!

GM-Tech · July 31, 2005

I was told by a mechanic that GM is aware of this but has not posted anything on it because they fear liablilty would cost them.

Was this just something he dreamed up, or does he have some facts to back up his statement? I suspect it's a personal opinion. What liability? This is hardly a safety issue.

As for your tensioner... if you can pull it down with only your hand to put the belt on, you have a problem there.

jsmca22 · July 31, 2005

I'm not saying it was easy, I just put my two fingers in the pully side groove and pulled it down long enough to get the belt in position, should it be harder than that to do?

GM-Tech · July 31, 2005

I'm not saying it was easy, I just put my two fingers in the pully side groove and pulled it down long enough to get the belt in position, should it be harder than that to do?

Hard to judge from what you're saying, but I think it would be rather difficult to do with just your hand.

jsmca22 · July 31, 2005

Could this be causing the belt to snap, they are not melting apart from a compressor or clutch stopping, they appear to be snapping in two from a sudden jerk or something. Is there a way to check the amount of tension the belt should have on it? or is there a way to check the amount of tention the tension pully should be applying?