azabrnski

'06 Silverado LT, 4.8L 82,000miles

The past few days I have noticed that my Temperature Gauge on the dash is indicating that something is going wrong inside my engine. Two days ago, I lost heat in my cab for a few moments, looked down at the gauge cluster and noticed that my temp reading was at or near the lowest reading 160 after driving for 20 minutes. Suspecting Thermostat is stuck open. Kept my eye on it, and it crept back up to normal operating temperature. Last night, and this morning I heard my electric fan cut on, and stay on for longer then usual. Looked down at my gauge this morning and noticed that I was running at almost 260 after driving for 35minutes. Hoping thermostat is stuck closed. As I sat out front my shop I let the engine idle, and it started to cool almost immediatly but in 10 degree increments, jumping those 10 degrees. I'm not sure what it is. AF is full, so i'm suspecting that it may be either my water pump, or my thermostat. I want someone to tell me that it isn't my water pump and that it is just the thermostat. I'm not ready to do the water pump yet!

tsduke

Water pump problems would usually either have a leak and/or noise associated with it. Thermostat is certainly the cheapest place to start with. The odd thing is in my experience the thermostat typically sticks open or closed, not both.

Silverado02

If you do have to replace the water pump, make sure you use the gaskets from the dealership, because the aftermarket ones and the ones usually included do not work well. Thermostat is not a bad place to start though, 15-20 bucks usually. New fluid is always a good idea too. I did this on my 02, a little different accessory setup, but overall still the same.

Sam Kent

Did you solve the problem? My temp gauge fluctuates between the 1/4 point and the 1/2 point, going up and down as I drive. Changed the thermostat, same problem. Changed the water pump, same thing persists. Thought about flushing, but I did that about 18 months ago (separate issue...changed radiator core).

azabrnski

My problem back then turned out to be a leaking water pump housing, causing a loss in fluid and Air to enter the cooling system. Air would get trapped stopping the flow of fluid causing temp needle to peg(airlock). When the air finally passed the cold antifreeze would drop the temp down dramatically showing the low temp.
In your case, if everything is changed and properly fitted and bled, your next step would be to look into wiring harness and or temp gauge

Sam Kent

Bled properly, eh. Now that is a good question. All I did was add fluid. Suppose here could be an air lock someplace...hadn't thought of that but it makes sense as the possible problem. I'll look into it. Thank you for the reply.