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engine overheating


New Member
Aug 15, 2007
I have a 2003 Av 5. 3 with z71 off road package. It has the tow/haul button which seems to work fine. I am having one problem. My temp gauge sits steady at 212 Idle or hwy speed, until I am towing my trailer which if I take on any grade it starts to rise rapidy. soon as I pull over it drops quickly down and even goes lower than where it usually sits on the gauge. If I'm going downhill the gauge drops to the mid 170-180, then soon as I'm on flat ground and at cruising speed, it sits at 212.
I have 64,000 mile on my Av. Does anyone have any ideas what this problem is.
Do I have a Rad, thermostat, fan or waterpump problem

It could be any of the above I would start with the fluid level, is the reservoir normal level
Any fluid on the gargage floor.
Seems normal to me....

when sitting in Garage idling...
  water pump is not pumpng a lot..
  Fan is not sucking alot of air across radiator...
  and 212 is under limit of being HOT
  Truck comes with 180 F thermostat...

then when you drive off it will drop a bit as it gets fresh cool air and more water flow... but eventually when driving long steady state distances it will stabalize above 180
We tested to see if we had a problem and took our 19' Trailer out and got about 30 miles out and as soon as we tried to climb a slight grade it started to overheat. I have no fluid leaks and of course the dealers want to start replacing rads, fans and thermostats. I'm new to the Av and it only has 62,000 miles.
Can anyone give me the heads up with any problems these Av's have .
I also had the front end checked and the CV boot and tie rod had to be replaced , they say all is good, yet i still feel something loose on the steering wheel.
Loose wheel = intermediate steering shaft, plenty of discussion here on that.

You may have a weak fan clutch.  If your cooling system is tight and properly sealed, I'd look there next.

Being an '02, you should already have the transmission oil cooler.