I have a 2011 Chevy Silverado 2500 with a 6.0 L. I never noticed this before because I was living in the south and never really had to increase my cab temp too much. Well I just moved to northern MI. Shortly after I moved here I had to replace my oil pump. Just before winter. once I was done I noticed when I would drive or when truck was at idle if the temp setting in the truck was above 75 the engine temp would rise and come back down. Now the hotter I kept the inside temp setting "say 80-90 degrees" the fluctuation would be more often and stay hotter longer. I have flushed the coolant and added the desired amount. It still happens. I cant seem to find a leak but with weather conditions its been hard to check. Any kind of helpful information would be great.

  • Sounds like it could be a thermostat.
    – GdD
    Apr 2, 2019 at 14:28
  • Welcome to Motor Vehicle Maintenance & Repair! Does your Silvy ever actually overheat (get into the red zone on the temp gauge)? Or does the temp just meander across the dial, but never really hits the red zone? Apr 2, 2019 at 17:04
  • This is going to sound stupid on my part ... but are you sure you don't have the 6.2L L9H or even the L94 engine in your truck? Not that it matters to your problem too much, because besides the displacement, are pretty much the same engine (HP/TQ ratings are a bit different, but the mechanicals are still the same). What I'm seeing is the 6.0L Vortec engine was last put in the trucks around 2009, but I could be wrong. Apr 2, 2019 at 19:12
  • When I first brought the truck back on the road I parked it at work and let it idle for a minute while I waited to walk in. then my truck started to ding at me and when I looked down the gauge was almost pegged out. Apr 3, 2019 at 19:42
  • Ive checked the oil and coolant and don't think I blew a gasket or cracked anything. Apr 3, 2019 at 19:42

1 Answer 1


most modern vehicles now have two thermostats .and they are integrated in the coolant flow.and preset.. usually one will be directly in the collant flow from the top of the engine and the other will be fitted to the oil cooler exchanger . Its the one fitted to the oil cooler tha i would suspect as sometimes this will fail and start opening early or late depending on the way the capillery in the stat is oriented . add its the way id first direct attention .. also ensure you are using a correct type coolant ..

  • Thank you. I did go but a thermostat today to try. When I originally put the motor back together I didn't realize it but I mixed two coolants. Ive since flushed and added only one. Apr 3, 2019 at 19:40
  • This engine is still an LS based engine, which only came with one thermostat. Apr 27, 2020 at 2:42

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