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Blazer noise

'91 Blazer, S10, 2wd, 300,000 mi …when weather cold, and car cold, I hear a loud slapping sound that I thought was a fan belt, but checked and they are ok…when car warms up, or when weather warm, I don’t hear the slapping… sounds like belt against plastic,???

timing belt/chain slap (is it a 4 or 6 cyl.)?

6 cyl… 2 wd… it’s been doing it since 2009…would a timing belt only do this when it’s cold but not when it’s warm? Got any idea why it’s slapping or what it’s slapping? I’m obvioulsy not a mechanic, but I thought timing chains/ belts just broke… thanks for your input…

per my mechanic, the '91 Blazer S10 V6, doesn’t have a Timing Belt…

Remove the belt before starting and see if the noise is gone. That will help narrow it down to belt or a belt driven component. And yes you’re correct. Whether this vehicle has a 4 cylinder or either of the V6 engines they’re all chain driven.

I’ve heard t-belt slap go away on a warm engine, t-chain slap I have never heard go away on warm-up.

That would point to a tensioner problem, then. When was the last time the tensioner was replaced (if ever)?

(I mean for the serpentine belt)

I take it this is the 4.3L engine? You may have to remove the timing cover and see if there are any interference marks but the whole idea about the noise going away after warm-up does not point to a timing chain issue (there is no tensioner)

Concentrate hard on something external before any type of teardown