GM-GMC: 2004 GMC Overheating, gmc safari, clutch fan

Question
Hello,

I have a 2004 GMC Safari getting ready to top 150,000 miles. I do cable installs with it and it is my livelihood so it is important for it to run good.

I have been in the Rocky Mountains lately doing installs and when I was going up the mountains I can only go about 40 mph without the vehicle revving to hard. On my way back a couple weeks ago as I neared the top of a pass I noticed my temperature gauge at 260 degrees and pulled over. When I was going downhill it was fine but going uphill it would tend to overheat again. Even some of the hills I thought shouldn't give the vehicle issues, give it problems. What I thought used to be hills of no problem now cause me to go super slow and cause the temperature gauge to red line.

I have had it in to have it checked but not sure how much checking they did. I told them a friend thought it might be the Thermostat and I guess they figured I knew more then them so that is all they changed and 2 days later it was overheating again going up another steep incline around where I live. Trying to figure out what might still be wrong and where to start first.

Thank you.


Answer
You definately don't want to be overheating your engine this will result in further damage that can be very costly.  A couple of things to look at...Ensure that your clutch fan is working properly, it helps draw air through your radiator to cool things down.  When you spin it by hand there should be  a slight resistance, it should not spin around and around.   Also look to see if any fluid has leaked out of the centre area, it is oil filled and are known to leak.  You can also try replacing your radiator cap.  It is a cheap part, but if it won't hold pressure it will cause an overheating problem.  One last tip is to turn your heater on hi on the highest heat setting when the van is running hot, this won't fix the problem but can help to remove some heat from the cooling system and may avoid engine damage.
Hope this helps