Wierd overheating problem

moonenn3186

Founding Member
Jan 9, 2002
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Dubuque, Iowa
I am running a N/A 351w 11:1 long rod (450hp give or take)

I built the motor with a high flow water pump, SCE composite .060 headgaskets, 180 Mr. Gaskter thermo, Summit Alum radiator.

On break in, and about 300 miles of easy driving with no cooling problems whatsoever- I got on it. About 3/4 way down the 1/4 (shifting at 4500 with 3/4 throttle) when I noticed the water temp moving fast toward boil point (auto meter guage)

I replaced the thermostat - no help, radiator cap no help, fans work.

Funny thing is when engine is heating up with the radiator cap off the water seems to act as a volcano off and on shooting up - then the temp guage moves up 30 degrees a second, then slowly rise, up 30 more degrees . . . .

then I shut it down . . .

Is this a headgasket or air bubbles?

:bang: