trailblazer

[Charley]

Wife's 2003 trailblazer when cold has a high rev sound as soon as you go about 2 miles it goes away any ideas. Thanks

[Macgyver55]

Sounds like a bad fan clutch description to me, (if it has one) I'm gonna go with fan clutch unless someone says it has electric fans.

[DTro]

I remember my Bravada doing the same thing. From the research I did, I think that it was considered normal.

[Charley]

dtro-- So you didn't do anything? This started on Thursday.

Mac-- How do you now if it s bad?

[DTro]

No I never did anything. Maybe it's something different I'm thinking about, but when the engine was cold, it would "roar" for a few minutes but wasn't engine related, as the RPM's were stable.

But then again, it always had done it, if this is something that just started for you, I'd probably have it checked out.

[Macgyver55]

Some amount of "roar" is normal during warm up. If it is acting much differently than it always has in the past, its a pretty good indication that something is going wrong.

In addition to more technical ways, there are a few simple ways to check it. The simplest ways are obvious. When the engine is cold the fan should NOT spin free. when it is hot (after warming up) it should spin free. If the fan clutch is leaking it's bad or going bad.

If I recall correctly there was either a service bulletin, or a recall on the Trailblazer fan clutches, so its very possible that is the culprit.

[Scott K]

Also with the engine off, you can grab it and spin it to see if it feels like there is a rough bearing in it, also wiggle it to see if there is a lot of wobble side to side in it.

[Jeremy airjer W]

Wife's 2003 trailblazer when cold has a high rev sound as soon as you go about 2 miles it goes away any ideas. Thanks

Does it stop after a certain amount of time or will it always make the noise?

I'd vote for the noise coming from the clutch as well. There a few things to test before condemning them but they use to be pretty common to go bad.

[98prosport]

Is this an L6 or V8? The 6 cyl has a computer controlled fan clutch. There could be a problem with the wiring or the fan clutch itself. Is the check engine light on? If so, the codes could point you in the right direction. Simply spinning the fan will not give you a correct diagnosis.

[Charley]

98pro-- L6. No check engine.

[Jeremy airjer W]

Simply spinning the fan will not give you a correct diagnosis.

unless the fan is frozen!

[FM_Mike]

Sounds like the fan clutch to me also. I have a 2002 envoy with the I6. It has does it intermentatly for the last 3 years. I have never thrown a code for the the fan clutch and comes and goes with the roaring sound. If it starts to get real bad it will strugle during the summer in hot weather with the AC cooling also.

If you google trailvoy you will get a lot of info on the fan clutch and replacement options. Also other good info on the sight. Hope that helps.

Mike

[Charley]

Thanks for the info guys.