Engine running a little warm

[EfiniMotorsport]

My 04 Yukon Denali has been running intermittently warm lately. I've got about 125k on it and replaced the water pump and thermostat less than 500 miles ago. It runs anywhere from 1 dash below half to almost 3/4. There doesn't seem to be any regularity to it either. sometimes idle is right at half and sometimes cruising is a few hash marks above. Other times it's the other way around. My heat also stopped working but I don't think it's related. I get heat for a minute then it cools down to luke warm at best. Both issues started happening in the last week or so. Im hoping the no heat issue is a blend door and not something more serious. I just had to replace the knock sensors again because the first pair I put in didn't work right.

 

[Rocket Man]

What brand water pump did you put in? If it’s not Gates or AC Delco it might have quit already. Hopefully you learned your lesson on buying cheap parts when you had to replace the knock sensors. Let me guess- those were Dorman, right? I sure hope you put AC Delco ones in the second time. The heater issue sounds like you’re not getting water circulation ie water pump issue or else you have a blockage or possibly air in the system.

 

[EfiniMotorsport]

I don't remember the brand of the water pump. It was the whole assembly with the pump housing and thermostat from Napa. I don't remember the first brand of knock sensors but the new ones are ac delco. I doubt it's air in the system as I changed the water pump months ago and it worked fine up until recently. The only thing thats been done to the cooling system is taking the hoses to the throttle body off to change the knock sensors. Any way to test for water not circulating? I get as hot as 230 degrees when reading through OBD but it doesn't stay there long.

 

[Rocket Man]

I don't remember the brand of the water pump. It was the whole assembly with the pump housing and thermostat from Napa. I don't remember the first brand of knock sensors but the new ones are ac delco. I doubt it's air in the system as I changed the water pump months ago and it worked fine up until recently. The only thing thats been done to the cooling system is taking the hoses to the throttle body off to change the knock sensors. Any way to test for water not circulating? I get as hot as 230 degrees when reading through OBD but it doesn't stay there long.

Squeeze the upper radiator hose after the engine is warmed up. You should feel the flow. If not, water pump or thermostat but the thermostat usually sticks open or closed so it’s either too hot or too cold but doesn’t fluctuate.

 

[Danny3737]

Fan clutch?

 

[EfiniMotorsport]

I'll check the upper hose tomorrow. I'm going to be swapping to an electric fan in the next month or two so if that is the problem it gives me more reason to upgrade.

 

[Tonyrodz]

I'll check the upper hose tomorrow. I'm going to be swapping to an electric fan in the next month or two so if that is the problem it gives me more reason to upgrade.

How are you gonna run the fan? On a switch or through the pcm?

 

[EfiniMotorsport]

Sometimes the simplest answer is the right one. I was about half a gallon low on coolant. Topped it off and I was fine. I'm going to run the electric fan from the PCM

 

[Doubeleive]

Sometimes the simplest answer is the right one. I was about half a gallon low on coolant. Topped it off and I was fine. I'm going to run the electric fan from the PCM

if you topped it off properly when you did your work then you have a leak (somewhere) or...the engine is eating it (happened to me before)

 

[EfiniMotorsport]

I forgot to top it off and I have a leak. Got to replace the radiator now. Going to do that, electric fan, and trans cooler all at once. Is there any reason not to bypass the coolant through the throttle body? It's a pain to have to pull it to pull the manifold and it will clean up the engine bay some. There's going to be a lot more room with the efan