Hi,Since i bought my denali 4 years ago my temp gauge showing about 212F the needle always at the mid of the gauge summer , winter cruising at high ways or even if the car a stop point but now a days i noticed that at high way the temp decreases but what got more worse that the temp needle will go to almost 0 while i am driving in dashboard i am getting Engine Hot / AC Off no engine code ,i stop the car open the hood and check the radiator hose i found not too hot it is warm i can keep my hand on it ,i noticed this porblem starts after i changed the lifters ,and intake valves i had done some searches on google and found some GM owners got similar problem they were talking about water pumps and t.state so what do you guys think what to start with ?

 

Seems no body have any info ,time to visit dealer

 

Did you install a 160 degree thermostat recently? There is talk of a similar situation on "Corvette Forum" about guys having this problem after a thermostat change to 160 on cooler days when starting off especially with a cold engine.

 

No i am still using the stock thermostat but i think the thormo is not working well i will get new one and see what happen.

 

Given the gauge goes to "0" when driving, it sounds like an electrical problem. [As in wiring or sensor.]
Have you done a scan to see what the system is seeing? [I see HPT in your sig.]

 

Problem solved ,when i open there was no thermostat i think the guy who change the lifters and intake valves forgot to install it .that why the engine took long time to warm