Mild Overheating (240 Degrees) During Normal Driving

corinthian-brad · April 3, 2008

I have a 2005 sierra 1500 5.3L 4WD. I noticed the other day that the engine was running a little hot, and the fan was running even during short trips. It's not hot outside yet, and I haven't been running the AC or anything. One thing I noticed is that the temp goes up a little bit when at a stoplight, then runs down a bit once you get moving again. It's not running in the 210-212 range - which I think should be normal. It's around 235-250 degrees. Any insight as to why it might be doing this? Fan clutch? Water pump? Radiator? Any help would be much appreciated.

Thanks in advance!

thecraft · April 3, 2008

Check if your thermostat is opening all of the way.

corinthian-brad · April 4, 2008

Thanks for the recommendation Thunderstruck, but I have a confession - an embarrassing confession at that. I checked my coolant level last night, and found that it was quite a bit low (I just bought this truck from a dealership, so it didn't occur to me that the coolant might not be full). Chalk this one up to laziness and stupidity. I hesitate even to admit it, but hopefully nobody else will waste time on this one.

Thanks again!

bossier62guy · April 4, 2008

Thanks for the recommendation Thunderstruck, but I have a confession - an embarrassing confession at that. I checked my coolant level last night, and found that it was quite a bit low (I just bought this truck from a dealership, so it didn't occur to me that the coolant might not be full). Chalk this one up to laziness and stupidity. I hesitate even to admit it, but hopefully nobody else will waste time on this one.
Thanks again!

Shouldn't you have gotten a "low coolant" light? I wouldn't be too embarrassed about posting before checking things out either....it's good that you figured it out on your own....builds character sometimes

corinthian-brad · April 4, 2008

Hey John, thanks for the kind words...

no - no low coolant light, that might be an issue in and of itself... but it's been operating just fine since I added the coolant, so I'll keep my fingers crossed

thanks again!

bossier62guy · April 4, 2008

Hey John, thanks for the kind words...
no - no low coolant light, that might be an issue in and of itself... but it's been operating just fine since I added the coolant, so I'll keep my fingers crossed

thanks again!

I know my 02 will give you a warning if the coolant in the overflow gets low.....they may have done away w/ that for the 05 but I doubt it....you're welcome by the way.

Zembonez · April 4, 2008

I would make sure you aren't losing coolant somewhere though.... That lost coolant had to go somewhere.

corinthian-brad · April 17, 2008

I would make sure you aren't losing coolant somewhere though.... That lost coolant had to go somewhere.

Okay - now I'm getting worried... I am loosing coolant - and it's not leaking out onto my driveway! I seem to have to put coolant in about every 150 miles... I know when it's getting low because the truck will start to run about 10-15 degrees above normal. I know this isn't good - so where could the coolant be going? Obviously it's getting consumed by the engine somewhere...

HELP! I just bought this truck used about a month ago - w/ 80,000 miles on it.

Thanks

2004Yukon · April 17, 2008

I would make sure you aren't losing coolant somewhere though.... That lost coolant had to go somewhere.

Okay - now I'm getting worried... I am loosing coolant - and it's not leaking out onto my driveway! I seem to have to put coolant in about every 150 miles... I know when it's getting low because the truck will start to run about 10-15 degrees above normal. I know this isn't good - so where could the coolant be going? Obviously it's getting consumed by the engine somewhere...

HELP! I just bought this truck used about a month ago - w/ 80,000 miles on it.

Thanks

Water pump perhaps. 80,000 is close to the magic number for some. Often times you will not see any outward sign of leakage.

Jay