Over heating?

[Henry_dry]

Driving around town the other day and I noticed my fuel mileage was buried. Looked up and noticed my temp gauge was also maxed right out. No chimes were going off or any engine lights or warnings on the DIC. Getting pretty annoyed with this truck as it has spent more time at the dealer than it has on the road.

The dealer sent a tow truck. Now they say they can't replicate the issue. Had anyone else run into this?

[Henry_dry]

I attached a picture of my dash while this was happening.

[SouthernSilveradoGuy85]

Well you can always go show that picture to them. It could be a few things. thermostat, radiator leak, low on antifreeze/coolant. electric fan not cutting on or not spin as fast as it should.

[bdbake01]

Wow. That temp gauge is pegged. Did you lift the radiator cap?

[dcheeseman]

Bad stepper motor....or ground to it!

[txab]

If your temps were really that high, you should have been getting poor running conditions and some engine pre-detonation going on. Agree with earlier poster, stepper motor, sensor or grounding issue possibly

[pm26]

I would say that the coolant temperature sending unit is the biggest suspect. These are variable resistors and since more and more of these parts are made overseas and quality control is questionable, failure rates may be higher than previously. if the engine really overheated, you would hear the coolant boiling, could see some steam coming off. And the engine would probably jump into the limp mode, not allowing the truck to be driven at normal speeds. Even my 1996 boat with a fuel injected 302 cu in Ford has that feature.

[gone_fishing]

I'm leaning towards something wrong with the gauge. If the engine was really overheating you should have seen a warning on the DIC.

[sahls01gmc]

Your seatbelt is unbuckled, while using your phone while driving! Just messin with ya

 

 

I'd say it's a gauge problem, not mechanical. You would have noticed something not running right if it was up that high. Did you pop the hood and check anything?

[pm26]

My experience over the years is that the gauge is almost never a problem. The sending unit is. I have seen this both on cars and trucks, and boats.

 

The gauge simply receives a voltage signal from the sending unit and if the needle moves on the gauge, the gauge is usually good.

[Henry_dry]

Thanks for the input everyone.

Sahls- please don't call the police on me. Hahah

I didn't pop the hood. It didn't seem to be hot though. Couldn't smell anything burning and the hood didn't seem hot to the touch. I had the girlfriend with me so we just went back to the house and swapped vehicles and continued on our way. The ole' sunfire never let's me down.

 

The only thing I noticed that was really different was the gas mileage in the DIC. Do you think this would have cause the computer to think it was running hot? Therefore burning more fuel? In that case it should have went into limp mode or at least a warning.

I showed the service department a video of the dash(same as that picture) and they decided it would be best to tow it, so they did. Once they had it in there they can not replicate the problem. Hopefully it happens again, maybe they will do something about it.

[sahls01gmc]

Hmmm, I think your mileage issue is a different subject. Did you let it idle for a long period of time recently? Have you hand calculated it is all well just to verify?

 

I definitely think it's a warrantable repair. That sucks you're having so many issues with you truck. Hopefully it all gets straightened out so you can enjoy it!

[B2E2RUN]

My experience over the years is that the gauge is almost never a problem. The sending unit is. I have seen this both on cars and trucks, and boats.

 

The gauge simply receives a voltage signal from the sending unit and if the needle moves on the gauge, the gauge is usually good.

Then you haven't owned a GM truck in the last 15 years. The stepper motors are notorious for failing. If it was the sending unit, the truck would have shut down, or at least went into limp mode.

Dealership should just warranty the cluster.

[fondupot]

im guessing the the sensor or the gauge is broken.

[pm26]

Then you haven't owned a GM truck in the last 15 years. The stepper motors are notorious for failing. If it was the sending unit, the truck would have shut down, or at least went into limp mode.

Dealership should just warranty the cluster.

Yes, I have owned a GM truck for the past 9 years, but I never encountered a bad coolant gauge, or any other gauge problems with it. Everything else I have seen with incorrect coolant temperature gauge indication was always the sending unit, including those in several Mercedes cars. Maybe GM trucks have a history of bad gauges/instrument clusters.