My 2002 Chevrolet Trailblazer LTZ is making a noise 1st 5 minutes driving.

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I had the water pump and fan clutch (after market) replaced on my 2002 Trailblazer 2002 LTZ. Now when I start the car and drive I hear the engine running faster 1 vs .5 on my RPM Tack guage. I also hear an atypical loud noise when driving which goes away within 5 minutes. Within 5 minutes the engine sounds normal. This occurs even if I make a short stop for 45 minutes running an errand like stopping at a business. It is NOT like reeving the engine. Maybe a jet engine which stops after 4-5 minutes. The Goodyear garage says they do not hear it but it is very pronounced. I left the car overnight at the garage so they would hear it cold on start up. They initially said it is the after market fan clutch ($366) and now think I should buy a GM part for $400 more. They are keeping the car hoping to hear and understand the noise before putting in or replacing more parts. The water pump and fan clutch were replaced by Goodyear with after market parts. The problem occurred after this replacement.

What makes this problem better or worse?

Starting cold engine and totally goes away in less than 5 minutes

How long has your 2002 Chevrolet Trailblazer had this problem?

Since I had the water pump and fan clutch replaced.

Visitor

in Pickerington OH

Nov 26, 2018

1 Reply

Popular Answer

pushrodon Nov 26, 2018

So you suspect that your fan clutch is defective. One of two conditions is possible. If your fan is roaring like a jet engine after it has warmed up, DO NOT TEST. It's already confirmed that the clutch is locked up and needs to be replaced. Normally, it will roar a little on startup and should quiet down as it warms up. If it is locked up, it's not bad to run it like this but power and fuel consumption will suffer and you may get a CEL with a code about the fan speed. The other possible condition is that the fan is not working enough. The engine may or may not be getting overheated but a lot of times, A/C performance will suffer while idling but will be better while moving. You may or may not be getting a CEL with a fan code. It might not be overheating because the residual friction is spinning the fan just enough to pull a little bit of air.. (It is quite possible you do not have a problem here)

pushrodon Nov 26, 2018

It is also quite possible since the *electro viscous fan clutch* is working properly NOW - it just sounds different to you than it did before..

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