1990 Mazda Truck overheating when going up hill.

Tiny
PUUNUI
  • MEMBER
  • 1990 MAZDA TRUCK
  • 4 CYL
  • 2WD
  • MANUAL
  • 18,199 MILES
Takes a while to reach normal temp. Then when going up long hills like the freeway or highways it starts to overheat. When I pull over and let it idle it goes down. Or if I make it over the hill and put it in neutral and roll down the temp goes back to normal.
Sunday, April 27th, 2008 AT 8:09 PM

3 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Test the thermostat or replace it and make sure your coolant level is correct
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Monday, April 28th, 2008 AT 5:36 AM
Tiny
PUUNUI
  • MEMBER
  • 2 POSTS
I just put an new one in.I filled it to the top. How can I test the water pump?
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Wednesday, April 30th, 2008 AT 2:28 AM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
One way to test for a bad water pump is to squeeze the upper radiator hose when the engine is hot and idling. Careful, because the hose will be HOT! If you do not feel much coolant circulating through the hose when you rev the engine, the pump may be bad. The other cause might be a bad thermostat that is not opening properly (remove and inspect the thermostat), or a clogged radiator.
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Wednesday, April 30th, 2008 AT 7:23 AM

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