Serp belt


#1

my motor makes a rythmic clunk/click sound at idle. would a missing chunk of serp belt cause a sound like that?


#2

Yes, replace it with a Goodyear Poly-V before you get stuck on the side of the road.

Ed B.


#3

It’s possible, but there may be other causes as well. A good mechanic can pin this down in very little time. A new belt would be a cheap fix, if that is the problem.


#4

likely.
With that much already missing…change it today !
Then see if the noise goes away.
If not the belt then maybe a pulley or rotating device like a/c , p/s, or alt.
Injectors can tick too.

I wouldn’t go much longer on that belt.
Mine looked better than yours yet was old and hardened. Once when the a/c compressor kicked on it caused just enough drag that the belt slipped off and became spaghetti is seconds.


#5

Doc, did you look at that belt? Or should I say “what’s left of” that belt? I’ve never seen a belt that bad.


#6

I recommend a Gates serpentine belt


#7

It really doesn’t matter if something else is causing the noise. You need to replace the serpentine belt anyway,. Then see if the noise is gone. I’d do it this weekend.


#8

Had to remove alternator to reach thermostat. The trailblazer L6 motor is packaged rather oddly. I just happened to see missing chunk of serp belt. I don’t know if that is only missing chunk. We got 2 recent used cars. Turns out both have various degrees of missing maintenance.


#9

A hunk of missing belt can certainly cause a knocking sound and it may even mimic a bad rod bearing to a tee.

My wife called me once from here mother’s house about the engine making a knocking sound.
Expecting the worst (and even more so after firing it up and hearing it) I was greatly relieved to find that once the hood was up the problem was nothing more serious than a belt which looked very similar to yours. New belt; problem gone.


#10

And that is one hunka-hunka burnin’ rubber missing. Apologies to the late Elvis Presley.


#11

@mountainbike Sorry, I did not take a good look at the belt; now that I have, it obviously needs replacing right away!

Once replaced, we can look for other causes if the noise persists.


#12

Replace the belt as others have already suggested. If it breaks in the boondocks…“a rythmic clunk/click sound at idle” will be the least of your worries.


#13

That’s what I figured, doc. That missing chuck is a definite clunk-maker, and I’m guessing the rest of the belt has a few more whappers and thunkers on it. If it isn’t changed. it’ll all end in one big pop any time now.


#14

I had to replace a belt in the bad part of Minneapolis once and its not fun. I always carried a spare belt, but even spending 15 minutes under the hood with your back to everything else and unarmed is not something I would recommend.


#15

Bing, you’ve raised an excellent point. In the old days, one could change a fan belt with a few basic tools and some creative verbage. But it’s wise to keep the serp belts used by todays cars in good shape because changing one of those on the side of the road is well-neigh impossible. On a typical FWD car of today, the corner needs to be jacked up and the wheel and fender apron removed just to access the from of the engine. Then one has to deal with the challenge of keeping the tensioner suppressed while threading the belt. Anyone who can change a modern serp belt by him/her self on the side of the road is a better man than I.

In short, the days of carrying an extra belt are pretty much over. It’s more essential to keep these things in good shape than it ever was.


#16

It was on the 86 Riv which was relatively easy to change. The 89 was too except required taking off a support rod. I wouldn’t even try it on my current cars but keep the old one in the trunk-why? If you do have a problem on the road, its sometimes easier to find someone to do it than to find the part. So I have the part with me. But I just change them out at reasonable times anyway.


#17

changed belt and noise is gone. motor has belt driven rad fan and i thought belt might be hard to sneak around blades but it was fairly easy.