car overheats

2000 CADILLAC DEVILLE DTS
129,000 MILES • 4.6L • V8 • FWD • AUTOMATIC
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QUINT45
  • MEMBER
  • 2 POSTS
I replace the water pump, radiator, thermostat, coolant tank with sensor and radiator holes. at times its running ok, then the gauge would go hot real fast then calm back down, sometime when I hit a bump in the road it triggers something and it goes hot again. but calms back down. I can feel the water boiling hot through the top radiator holes. then at times everything is flowing nice. I check the holes as well and everything checked out ok, coolant is flowing. help please?
Mar 28, 2017 at 11:53 AM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
pressure check and chemical check for a head gasket leak that may be the problem. then check ground wires on engine to battery and battery to body as you may have a loose one.
Mar 29, 2017 at 12:17 AM
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STEVE W.
  • ✓Experienced Mechanic
  • 15,367 POSTS
The lovely Northstar engine. As HMAC says, test it for bad head gaskets. They are sadly know for having the head gaskets fail because the bolts holding the heads on pull loose from the block. That can be repaired.
Mar 31, 2017 at 8:16 AM
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