[SOLVED] Serpentine belt fell off!! [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: [SOLVED] Serpentine belt fell off!!


clfaus
04-17-2010, 12:25 AM
So today I was driving on the highway and my serpentine belt fell off! I noticed the truck making a load roaring kind of noise when I would accelerate into passing gear a couple of times, but other than that didn't notice anything unusual. No loss of power or anything like that. The belt still looks to be in good condition, not worn or cracked or anything. Didn't get any check engine codes or anything. Haven't noticed anything out of ordinary until this trip today.

Any ideas of what to look at? I'm sure these things don't just fall off for no reason!

Thanks in advance for any help!

BTW, it's a 2005 Trailblazer. About 78K miles.

jacob789456
04-17-2010, 12:31 AM
If you have an EXT model it is possible that a longer belt made for the SWB version was installed or sold to you. This belt is an extra inch longer, however, I still cant see it falling off. Did you check all of your pulleys to make sure nothing broke off, especially the idler pulley or tensioner? Don't drive with out the belt or your TB will overheat because the water pump is not turning.

sLAsh
04-17-2010, 12:36 AM
dont know about the trailvoy but for most vehicles i would suspect the tensioner first

clfaus
04-17-2010, 12:37 AM
I don't have the EXT model. The belt was replaced by the dealer a couple of years ago and this is the first issue I've ever had with it. I wasn't sure what happened because all of a sudden I lost power steering and then the temperature shot through the roof. I pulled over immediately, hopefully the brief overheating didn't do any damage. Sprayed coolant all over when it bubbled out the overflow.

The truck is still sitting off the side of the highway. I'll get it towed in the morning. Just want to know some things to check for when I get it home. Thanks again for your help.

Robert1101
04-17-2010, 12:42 AM
So today I was driving on the highway and my serpentine belt fell off! I noticed the truck making a load roaring kind of noise when I would accelerate into passing gear a couple of times, but other than that didn't notice anything unusual. No loss of power or anything like that. The belt still looks to be in good condition, not worn or cracked or anything. Didn't get any check engine codes or anything. Haven't noticed anything out of ordinary until this trip today.

Any ideas of what to look at? I'm sure these things don't just fall off for no reason!

Thanks in advance for any help!

BTW, it's a 2005 Trailblazer. About 78K miles.
Your serpentine belt came off, the vehicle did not overheat without the waterpump working and it made a loud roaring noise when you would accelerate. Those are a lot of strange conditions at the same time. You have only one serpentine belt, correct?

clfaus
04-17-2010, 12:44 AM
Would a bad fan clutch cause it to throw the belt? That might explain the roaring noise that I heard when under hard acceleration. Any thoughts?

Robert - sorry if my original post was unclear. The roaring noise happened before the belt came off. The truck did overheat when it came off. Thanks.

Robert1101
04-17-2010, 12:52 AM
If you grab the fan blades and wiggle fordward and rearward do they move much? (without the belt) if they do the water pump bearings are shot. When you put the belt back on did the roaring noise go away?

SBR_RACING
04-17-2010, 08:04 AM
Right before my water pump bit the dust it was making a loud roaring sound which I thought was the fan clutch but finally my water pump locked up and burned the belt, so I would check/replace it if I were you.
Now after the water pump was replaced the fan clutch is making the tick tick tick noise in mine:hissy:

clfaus
04-17-2010, 10:00 AM
Thanks for the ideas guys. I'll check it out more thoroughly when I get the truck back to my place. It broke down about 100 miles from home! These things are never convenient are they.

RayVoy
04-17-2010, 07:41 PM
Usually, when any belt "flies" off, there is a mis-alignment with the pulleys.

For years, the belt stayed on, so the alignment was good.

Look for a loose and floppy pulley. Check the tensioner, the idler and all of the accessories pulleys.

My money is on the idler pulley.

clfaus
04-17-2010, 07:46 PM
Well, I finally got the truck back home. I checked and sure enough the fan moves back and forth quite a bit so it seems pretty sure that the water pump failed. My bet is that the pulley got wobbling and then threw the belt. I saw that there's a good write up on here on how to replace the water pump so I'm gonna have a go at it tomorrow. Thanks for all your help, this forum is awesome.

LMMJ
04-17-2010, 09:33 PM
Well, I finally got the truck back home. I checked and sure enough the fan moves back and forth quite a bit so it seems pretty sure that the water pump failed. My bet is that the pulley got wobbling and then threw the belt. I saw that there's a good write up on here on how to replace the water pump so I'm gonna have a go at it tomorrow. Thanks for all your help, this forum is awesome.

and the fact that the water pump pulley is smooth it isn't hard for it to fall off

clfaus
04-19-2010, 10:29 AM
Just wanted to update everyone that I did get this problem fixed. It was the water pump, the bearings were shot on the thing. Putting the new one in was pretty easy. The worst part was getting that big nut off that connects the fan clutch to the water pump. The pulley kept slipping, even with the drive belt on, so I had to go get a strap wrench to hold it. Once I got that in place, a couple good whacks with a hammer on a big open ended wrench got it broke loose. Getting the fan shroud assembly in and out was not much fun either, left some skin from my knuckles there to prove it.

All in all, not too bad of a fix. Thanks again everyone for all of your help.

the roadie
04-19-2010, 10:52 AM
All in all, not too bad of a fix.Congratulations. You would not believe the frustrating weekends some members have had doing that exact job. Some of them get frustrated too easily perhaps, but it CAN be a nightmare if they don't discover the whack-a-crescent-wrench trick.