2000 Sierra Overheating

[lurchy]

Hi everyone,

 

I have a 2000 GMC Sierra SLT with the 5.3 vortec engine and auto transmission with 114,000 miles. The problem began with a low coolant warning when I was on a steep incline. I added 1/2 gallon of 50/50 mixture dex-cool taking the reservoir to the max mark and everything seemed to be fine. I looked everywhere and couldn't find a leak. A couple of weeks go by and the truck starts to get slightly above 210, I checked the coolant level and it's still at the max. Now the truck climbs all the way to the 3/4 mark, it does this whether I'm driving or idling in traffic. I should point out that the truck isn't my daily driver and does a lot of sitting. It's usually only used on the weekends to work around the house or tow a small trailer. Does anyone know of common problems with this model of truck or help out in pointing me in the right direction?

 

Thanks!

 

[txab]

Have you checked the fan clutch or thermostat?

[mzodarg]

My guess is the thermostat. Low cost easy fix, to at least aliminate that as a possible culprit. If your real frugal, take the thermostat out and boil it in water with a candy thermometer, check the temp when it opens.

 

Mike

[Bad Bowtie2]

If the trucks been sitting alot, I would also replace the thermostat & Dexcool/distilled water. I bet the cooling system hasn't been serviced, correct??