1999 Pontiac Grand Am Engine Overheating

Tiny
RASCHT
  • MEMBER
  • 1999 PONTIAC GRAND AM
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 135,000 MILES
Engine started overheating. No coolant leaks; water pump working; cooling fans NOT coming on. If vehicle is going 30 mph or more engine runs hot (225-230) but does not overheat, but temp creeps up slowly. Normal temp in the past as been just over 200. Overheats at idle - up to 260. The cooling fans do work because they came on just for a second and turned off once - but do not come on if temp if temp over 230. I am thinking a fan temp switch rather than a fan relay. Any other thoughts?
Monday, October 27th, 2008 AT 6:34 AM

1 Reply

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Hi rascht and welcome to 2carpros

Test the engine coolant temperature sensor resistances-see below-Computer might not be getting the correct signal from the ECT therfore not energizing the fan relay on time. Also a problem with the thermostat could cause the ECT to read low-


https://www.2carpros.com/forum/automotive_pictures/12900_CTS_values_1.jpg

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Monday, October 27th, 2008 AT 6:54 AM

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