laswif

I have an '03 TB EXT...fairly happy with it (with 4 in car seats, the choices are limited!).

Lately when the weather is hot or humid and I accelerate, the engine makes a loud idling noise as if it was in neutral. The RPM don't seem much higher and the car does go forward, but the pick-up doesn't seem as much when this happens. Oddly, when the weather is not humid or cooler (80's or cooler), it doesn't seem to happen.

Tried this with the AC on and off, and that doesn't seem to make much difference - altho of late, I've had some problems with the AC getting as cool as it should be.

Any thoughts?

maxwedge

Tough to determine by your description what a loud idling noise is, does it sound like an airplane propelle,r loud wind roaring or rushing noise, like a house fan at high speed?

ScarabEpic22

If it is what maxwedge is saying, then your fan clutch is probably bad. Really common issue with a loud fan noise, worse gas mileage, bad pickup, and sometimes your AC doesnt get as cool due to there isnt much airflow over the condensor. Make sure if the clutch is the problem to get the new part number and have your PCM reflashed with the newest engine software.

__________________
-Erik

2002 Chevrolet TrailBlazer LT 4X4 -Summit White w/Oak interior
Many Mods, latest: EFILive tuned by (me)

laswif

Thanks to you both for replying...definitely not a propeller sound (no stacotto (sp) rattling, thumping). More like a loud fan roar or if I stuck the car in neutral and floored it. Yes, the gas mileage is worse, esp. in the city. And the AC thing is definitely noticeable.

maxwedge

Check with your dealer, there is a TSB for pcm software updates that may correct the fan problem, but if it is stuck on in the lock up position, it may have to be replaced.

ScarabEpic22

Yea, if it sounds like you are flooring it in neutral, get the software update first and then if it isnt fixed, get a new fan clutch. It will help a lot.

__________________
-Erik

2002 Chevrolet TrailBlazer LT 4X4 -Summit White w/Oak interior
Many Mods, latest: EFILive tuned by (me)

Darth Zavious

My 02 TB seems to be doing the same thing. It sounds loud on certain occassions. Like the engine is struggling or something. My noise comparison would be similar to that of a big bus. You know when they take off and you hear the engine somewhat roaring. I guess it sounds like a diesel engine.

ScarabEpic22

You have just won the need to replace your fan clutch!! But, before you do that, have the dealer update your PCM to the latest version, have heard an update helps. If the update doesnt help, time for a new clutch.

__________________
-Erik

2002 Chevrolet TrailBlazer LT 4X4 -Summit White w/Oak interior
Many Mods, latest: EFILive tuned by (me)

Darth Zavious

Thanks ScarabEpic22 for the info. I will have the dealer do this before it gets worse.

markbair

I took my car to the dealer because I was getting the "ticking" sound from the engine when it is idling. Of course it only did it on rare occasions, so the dealer couldn't fix it because he never heard it. I told it is was that fan clutch but he didn't listen. I understand though, I am sure people come in with their own diagnostics and they are 95% wrong. Anyway, 2 weeks later the truck starting making the "bus" sound that you speak of. I knew immediately it was the fan clutch, and it was stuck "engaged" all the time. Well, I took it to the dealer and the first thing they did was reprogram the software. 2 hours later they give it back and say, you are fixed!! I said hooray and started the car. I drove out of the dealer garage, stopped, put it in reverse and told them it still wasn't fixed. Do they not even test drive the vehicle to make sure it was fixed?? You could tell by parking the car in neutral and reving it up! Anyway, they replaced the fan clutch, and all is well. Finally. I am glad it happened before the car was out of warranty. Only 3000 more miles for that. Sorry for the lenghty reply,but that is my story!!