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2002 Trailblazer Running Hot

At 81000 miles I had the cooling system flushed and refilled on by Trailblazer. Ever since it is running 25-30 degrees hotter. I have changed the water [ump and the thermostat and still the problem persists. Is it possible something happend when the flushed and refilled or is it possible the gage is not reading correctly? Help!!

Running hot means the temp gauge is reading in the red zone. Is it?


No it is not in the red zone. But what would case it to run 30 degrees hotter with new clean fluid in it than it has forthe first 7 + years I have owen it?

I would recheck the thermostat, perhaps a higher temp one than oem got put in.

You went 7+ years before servicing the cooling system? And with DexCool in it? Buddy! When you do that, all bets are off.


I only had 80k on it shouldn’t the fluid last longer than that?

Let’s not cast dispersions on dexcool, as far as I know the big problems are with air in the system turning it to sludge, I made it fine to 96k on my 03 in o7.

Air in a cooling system with DexCool turns the coolant acidic, which eats away at head gaskets, heads, hoses, radiators, heater cores, etc… creating the sludge.

I’m not casting a negative eye on DexCool. That was done years ago when GM was sued by all the GM vehicle owners who’s engines turned to junk because of the claims made by GM about this coolant. Remember! They said it COULD go 5 years/150,000 miles before needing service. They never said it WOULD go 5 years/150,000 miles.


I believe you are over the time limit in the manual so it has exceeded it’s life expectancy. You do not have to have it replaced with dexcool.

What can I use other than Dexcool? Is there a replacement product and will that not damage the aluminum waterpump?

Peak Global, or universal was what I had.