I seem to be having an issue with my temperature gauge or something associated with it. A few months back it seemed like my truck would warm up to operating temp in about 5 minutes (of idling). Now it takes about 15-20 minutes of driving to get the needle off the C. The picture is from two days ago driving home from work 30ish miles, 60mph and the outside temp was about 55. This was the highest the needle got. Should I be worrying about this? If so what should I be checking? Thank you.

P.S. The truck is a bone stock 22RE w/ 196k miles.

 

I'd say your thermostat is stuck open. You'll get poorer performance and gas mileage, and no heat in the winter.

You might be able to rule out the gauge itself by turning the heat on. Is it as hot as you've come to expect? (This is a tough check to make in the summer time.)

But I can't really tell that from your picture; these gauges aren't calibrated and are useful for comparison purposes. But since you've noticed the change (comparison purposes), the thermostat is where I'd look first.

 

Thanks for the response Scope, from what I had read on here I was leaning towards the T-stat. But I have a record showing that it was replaced 52k miles ago back in '08, do they normally go out that quickly? The water pump and radiator were also replaced at that time if it matters...

And I have noticed a difference in how long it takes for the heater to blow warmer air. Is that directly related to the T-stat?

 

The Thermostat is not a "maintenance" item, so they have no fixed lifetime. Like most things, they break when they feel like it (I would hope they'd last the life of the vehicle, but I'm not too disappointed in 5 years.)

If the thermostat is continuously pumping all the coolant through the radiator, it will never heat up to where it is supposed to be. That same coolant goes through your heater core; lower temperature coolant, lower temperature heated air.

 

you're lucky that it's stuck open. It'll be worse if it stuck closed....I think that part is like 15 bucks or something.

 

Thanks for the help guys, it would appear the thermostat was the culprit.


Just installed the new one, and I let the truck idle for 5 mins or so. The idle was fluctuating a bit in the first few minutes from low to high and vice versa, before leveling off. Im assuming this is normal?

 

Does that black rubber look like part of the thermostat? If not, where did it come from? Having pieces like that roaming around in your coolant system can't be a good idea.

 

I have a similar problem currently. Except I get plenty of heat out of the blower. To the point where if I dont turn it down after about 3 mins, I might die of heat stroke.

I used an IR temp probe to check block temp, cooling line temp, etc, and they were all within what I would think is normal (around 185ish.)

Either way, Im checking it this weekend.

 

It would appear its part of the thermostat. Looks like a gasket thats on the underside.