I have a 2003 trailblazer with the straight six. I have owned it since new. I have around 65K miles on it. It has developed a loud ticking noise that comes and goes. It is especially noticeable at start up. Any clues???

I took it to a dealer and they reset the computer for $25.00. It fixed the problem. If this didn't fix it then it is the fan clutch which is $500.00 installed from dealer.
Ken

The ticking noise could be as simple as a bad fan clutch. The electro-mechanical fan clutches have been known to *tick-tick-tick* from the internal solenoid when they go 'bad'.

Joel

Thanks Joel, I thought it may have something in that area.
A local dealership said a computer program could fix the problem or replacement $500
Ken

Replacement fan clutches are not cheap, but not too bad to DIY.

Joel

I have an '03 trailblazer ext with the 6 cyl. and at every cold start this ticking noise starts and it is independent of engine speed. I first thought it was coming from the a/c compressor because sometimes the noise would come back when I turn on the a/c. It has been in the shop twice without a successful diagnosis because it only only lasts a few minutes, although the the fan clutch has been replaced for other reasons.
my chevy has 42000 miles
Does anyone have anymore clues?

Joe

I have an '03 trailblazer ext with the 6 cyl. and at every cold start this ticking noise starts and it is independent of engine speed. I first thought it was coming from the a/c compressor because sometimes the noise would come back when I turn on the a/c. It has been in the shop twice without a successful diagnosis because it only only lasts a few minutes, although the the fan clutch has been replaced for other reasons.
my chevy has 42000 miles
Does anyone have anymore clues?

Joe
i have an 04' with the exact same issue, i belive my fan clutch is bad, (viscous fluid leaking around fins) but i dont over heat past a few lines from the middle mark even on the hottest day as long as i am moving. the ticking noise has always been there if its cold out only , never if its warm outside.
i have searched for the noise but cannot locate it and have decided it causes no harm, and is hardly noticable.
my best guess is that the evap system purge solonoid is causing this tick tick tick.

i have shut the key off and restarted the truck and sure enough it goes away, this sound is not comming from the engine mechanical operation since it never changes speed from its hum drum ,, tick, onethousand tick, onethousand tick, onethousand tick, onethousand.
i dont think its anything to be concerned with, got 74,000+ miles on my TB and no ill effects have been seen from this tick.

Hope this helps somewhat even if just giving a calm to fear.

Josh

I know it's not the safest thing to do..:uhoh: But can you guys (carefully!) stop your cooling fan by hand on a cold/cool idling truck? I can easily do this on mine. I'm thinking for troubleshooting purposes, if you stop the fan can you still hear the ticking?

Joel

Could just take the serp belt off also, or unplug the fan.

Thanks for everyones time and help.
Ken

i have an 04' with the exact same issue, i belive my fan clutch is bad, (viscous fluid leaking around fins) but i dont over heat past a few lines from the middle mark even on the hottest day as long as i am moving. the ticking noise has always been there if its cold out only , never if its warm outside.
i have searched for the noise but cannot locate it and have decided it causes no harm, and is hardly noticable.
my best guess is that the evap system purge solonoid is causing this tick tick tick.

i have shut the key off and restarted the truck and sure enough it goes away, this sound is not comming from the engine mechanical operation since it never changes speed from its hum drum ,, tick, onethousand tick, onethousand tick, onethousand tick, onethousand.
i dont think its anything to be concerned with, got 74,000+ miles on my TB and no ill effects have been seen from this tick.

Hope this helps somewhat even if just giving a calm to fear.

Josh

Josh, thanks for the reply. I've only had the car for a few months and the ticking is consistent with every cold start. If you have 30K more miles than me then maybe i'll throw it off as a manufacturer defect. I was worried about the fan or a/c clutch seizing on trip and being S.O.L. I will be going to a chevy dealer soon for and O2 sensor and i'll see what they have to say about it.

Joe

I'll try that again, but I think when I first test drove it the dealer stopped the fan and i'm pretty sure the noise continued.

Joe

I know it's not the safest thing to do..:uhoh: But can you guys (carefully!) stop your cooling fan by hand on a cold/cool idling truck? I can easily do this on mine. I'm thinking for troubleshooting purposes, if you stop the fan can you still hear the ticking?

Joel
hey joel how goes it,
:::::::: EDIT :::::::::
should have read your post more carfully, relizing now that you said cold/cool idling truck. in this case yes i can stop the fan from moving for a long time.
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original post to follow
well i also thought about this stopping the fan stuff to see if the clutch was working, i used a soft handled pliers, i was able to stop the fan and within about 20 seconds while feeling for building resistance from the fan clutch engaging the fan just took off, that was before the fan was determined to be bad , and the clicking was still there then, my assumtion is that the clicking is unrelated.
hope we can figure this out as the clicking returned today ...of course....
josh

Yeah, the fan on mine spins even when not needed, but I can easily stop it & spin it backwards. It will eventually stop and coast in the direction of rotation. Josh, can you pinpoint your click to the intake manifold side? Maybe it's a noisy fuel injector? Also- like you say, the EVAP system purge solenoid is under there somewhere as well. The underhood EVAP schematic sticker is pretty non descript.:disappoin

Joel

Josh, can you pinpoint your click to the intake manifold side? Maybe it's a noisy fuel injector?

the hum drum as described with the tick ,,,onethousand etc etc , is too slow to be a fuel injector and it stays constant with engine speed. i truly think its the purge solonoid.
cold start, pressure/vapors have built up, warm gas colder air causes evaporation of gas. this is oppinion though call it an educated guess i dont know lol.

Goldcoater and Josh, I'd try like Max suggested. Pop the serp belt off and idle it for a minute, just to elimate any belt-driven, rotating elements from the picture.

Joel

i have determined that the ticking noise is comming from the evap solonoid purging. a stethascope (wife is mad at me) isolated it to this part. no to say thats golds issue, but that is the findings i have for now.
Josh