Cooling system

2006 CADILLAC STS
214,000 MILES • V8 • RWD • AUTOMATIC
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CECILIA BELL
  • MEMBER
  • 1 POST
Car is overheating. we replaced the radiator still over gear changed the hose, water pump and thermostat. still over heating. it is holding the radiator fluid now but when we tighten the radiator cap it overheats, but we loosen it and keep it loose it does not over heat. We have no ideas what it is now. we changed the whole cooling system. need help.
Aug 12, 2017 at 7:28 AM
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STEVE W.
  • ✓ASE Certified Mechanic
  • 15,200 POSTS
  • ASE Certified Mechanic
The Northstar engine is known for head gasket problems. I suspect that is the root cause of your problem. You can rent a pressure test kit and a combustion gas detection kit from many parts stores and run those tests on the system. It should tell you if there is a gasket issue.

https://www.2carpros.com/articles/head-gasket-blown-test
Aug 12, 2017 at 9:34 AM
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