fan clutch '02 TB

Hello,
I am concerned with my fan clutch. I have mentioned to the dealership that occasionally at start up, there is a very loud "revving" sound from the engine. The tacometer revs up high but i am not going anywhere. Then after a while, the engine seems to slow down a bit and then everything seems to level off. They told me it was just the fan clutch and that it was "normal". Now I read all of these expensive repairs that you all are having and I wonder if I should make them replace mine before the warranty runs out. I have 28k on my '02 TB
Thanks,
Scott

I have the same problem on my 2002 TB. However, mine is beyond the warranty. I've never had a problem with it but now I hear a loud popping noise under the dash for 2 seconds when I start my TB . I've read on this board that it could be the actuator cam. Any idea what this is?

Hello,
I am concerned with my fan clutch. I have mentioned to the dealership that occasionally at start up, there is a very loud "revving" sound from the engine. The tacometer revs up high but i am not going anywhere. Then after a while, the engine seems to slow down a bit and then everything seems to level off. They told me it was just the fan clutch and that it was "normal".

The tach (and thus also the engine) revving higher than normal from a cold start is the truck's computer simulating what the old-school "Chokes" used to do to help warm up the engine.

The dealership is right. This is normal.

It's running the engine faster on purpose so that the truck is responsive to your needs (hitting the gas pedal, cranking the A/C or fan, etc) without bogging down an engine that has not been properly warmed up yet.

Our 2002 Trailblazer takes about 10 minutes or so to reach standard temperature. Usually after only a few minutes, the fan clutch kicks out and gets quieter, meaning that the engine is warming up and is soon to be circulating the coolant through the thermostat. In colder months, it may take longer to warm up.

My recommendation is to not worry about it. It was designed this way.

-- Doug
ZEPCOM

I have the same problem on my 2002 TB. However, mine is beyond the warranty. I've never had a problem with it but now I hear a loud popping noise under the dash for 2 seconds when I start my TB . I've read on this board that it could be the actuator cam. Any idea what this is?

I don't think this is related to the fan clutch. I've read on gmtechlink.com of this:

2002-2003 TrailBlazer, Envoy, Bravada – Squeak/Rub/Scrub Type Noise in Steering Column Lubricate and remove material, per bulletin Don’t replace upper or lower intermediate shaft 02-02-35-006A

but I don't think that's what your problem is. Might still want to take your truck to a repair shop or the dealership (just ask for the "$40 mechanical check" of the area in question, they'll figure out what it is, and give you an estimate of how much it would be to fix it, just for $40. Sometimes that is what I am forced to do, since it's cheaper than replacing parts without an actual diagnosis of what is wrong.

Hope this helps...

Doug
ZEPCOM

Turn on the radio and forget about it. it's normal operation and been like that for me since day 1 july 01

Well, This problem is simply one of fan overspeed. Sometimes depending on the orientation of the fan clutch and the amount of time in that orientation, some of the viscous fluid will enter the working chamber of the clutch. Upon startup, the clutch will pump itself out, usually after accelerating up to 2000+ rpm. There is no problem with this issue, just a little noisy. In fact, the old style bi-metallic clutches had this issue.

However, I will say that if you hear this loud roar (jet engine) noise all the time, well, you need a new fan clutch. This does have a chance of happening as the TB's get over a couple of years on them. You will usually get a SES light along with it. You will hear a loud roar from the fan as the fan clutch is locked up, the car won't want to accelerate very well, and your shifts will get harsher.

Good luck.....

My 2002 TB is doing the exact same thing...How can a defective fan clutch cause poor acceleration?

Two things from what I hear/read.

These fan clutches are known to fail. When they start going bad the engine temp will vary more than normal. Keep an eye on your temp gauge.

Clicking noise in the dash will soon result in heater air flow going haywire, an actuator in the hvac is going bad. Look at a 400 dollar repair as it's buried deep in the dash.

Anyone having a fan clutch problem with their TB or Envoy If it is still
under warranty insist it be replaced. This is a $700.00 repair if you have the GM dealer to do it.

Already had 2 replaced on mine & I only have 14,000 miles!


Question.....since the part was replaced by the dealer & it is a GM part, then isn't that part that they put on warrantied for a year or something?
Even if you are about to run out of warranty & they fix it, then you should have another year or whatever it is left on the part?

Don't know if I am way off on this or not, but I would like to know the answer.

My 03 TB with only 23,300 miles went in the shop last week to have the fan clutch replaced...hopefully it doesn't happen again when it's out of warranty.