chevy trailblazer overheatiing?

Question

I just bought a 2004 trailblazer with 20,000 miles on it. I was recently sitting in traffic and i look down and the tempature gauge as all the way in the red, i took it it to get checked out and they can not figure out what is wrong with it, they said they had it sitting for 2 hours running and it did not overheat. it has not gotten to the red since then but it does run a little hot. does anyone know? they checked the hoses and fan clutch and all that

Answer 1

With 20K there shouldn't be any major issues. The TSB the guy was talking about was for "higher than usual" temperatures, but not for OVERHEAT (in the red). Deffinetly have the t-stat changed if it overheated. They are a pain on the TB, but it has to be done. It could have been compromised.

The cooling system does NOT need to be flushed, so dont waste your time/money on that.

The real thing is to try to keep track of all the factors that are occuring when it gets hot again. The dealer will need that info. Its tough when they are unable to duplicate it.

It could have been something as simple as an air bubble in the cooling system. They can cause "hot" spots.

The bulletin the guy was talking about is:

Some customers may comment on higher than normal engine coolant temperature gauge readings when operating the vehicle in very high outside ambient temperatures, and in stop and go or slow moving traffic.

Cause
Reduced air flow across the radiator and preheated air from stopped or slow moving driving conditions from traffic congestion may result in normally higher engine coolant operating temperatures as indicated by the temperature gauge.

Correction
Technicians are to reprogram the PCM with an updated software calibration. This new service calibration was released with TIS satellite data update version 7.3 available July 7, 2004. As always, make sure your TECH 2® is updated with the latest software version.

This new calibration will cause the PCM to command small amounts of additional fan engagement to control engine coolant temperatures and gauge readings closer to a customer perception of normal.

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Like i said this is for people who say its running hotter than usual or hotter than their old car. NOT for overheat. Overheat will not occur because of this bulletin.

Thanks! Goodluck

Answer 2

If it's overheated once, the thermostat needs to be replaced.

They're fairly simple to replace. Just a little messy with draining some of the coolant.

You might consider flushing the cooling system too.

Answer 3

Their was a TSB bulletin on this vehicle about the electric fan clutch check with your local dealer to see if it applies to your vin# .....

Answer 4

i heard they recalled some of the trailblazers, due to fire hazards. check with gm