Boiling over, but temp guage not reading hot, radiator cap shot??

Joined
Dec 2, 2003
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Rockville, MD
Ok, after doing some searches and reading through the FSM, I've come to the conclusion that the first thing I should do in trying to solve this problem is change the radiator cap.

Issue: Ever since my two stucks earlier this week the truck has boiled over 3 times. The temp guage shows slightly warmer than usual, but not anywhere near where it should be for the truck to overheat or boil over. When it has boiled over the truck has been working hard, but not excessively. This lead me to believe that the radiator cap might be worn out or damaged. Does my reasoning sound logical and correct? Thanks

Ary
 

brian

SILVER Star
 
 
Joined
Feb 7, 2003
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lebanon,pa
cracked head or blown HG, pumping air into the water jacket which then pressurizes the systems(more than it already is) and dumps the water out.

maybe?
 
Joined
Jun 22, 2004
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Portsmouth NH
Replace the cap and have the old one checked by a shop. Cheap money for a cap and may put other questions to rest about the cooling system and HG. Check for bubbles in the overflow tank after the new cap has been in place for a couple of days.
 
Joined
Dec 2, 2003
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Rockville, MD
I'm currently sitting in the 80 and just noticed that the RPMs are hovering just below 800 with the engine thouroughly warmed and the AC OFF. I wonder if this is at all related. Before these incidents this past week it ALWAYS idled at 600 w/ the AC off after it was warm.

Hmmm

Ary
 
Joined
Jul 20, 2004
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Chandler, AZ
How much mud is packed in your radiator, a/c condenser, a/t cooler fins? Dried mud is a great insulator, not to mention the air flow reduction.
 
Joined
Apr 4, 2004
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Los Angeles
Try the radiator cap first -- it's an inexpensive fix. My guess is that you are assuming that the thermostat and the radiator are working fine, thus the boil over is due to a loss of pressure through the cap.

I would get the radiator inspected by a radiator shop just to make sure. You could have a dirty radiator that's working at 50% or less.
 
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