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zelatore
08-25-2007, 02:16 PM
OK, not Donzi related but maybe somebody has an idea that can help.

One of the 454 Crusaders (454/350hp) in my 32 Carver shows very erratic temp at lower rpm. At idle, it's fine. Put a little load on it and run it around 1400-2000, and the gauge will climb back and fourth between 180 and 240 very quickly. Cruise at 3000-3200 and it drops down and stays around 190 just like the other motor.

I've switched sending units and gauges with no change. I've taken a laser temp gun and shot both motors and I get the same readings on both despite the temp gauge going out of control on one motor. When it's acting up, the gauge will jump from normal to Holy Crap! in about 5 seconds. It will go back just as fast, then climb back again...maybe it will stay hot, maybe it won't, but it always drops back to normal at cruising speed.

Since I can't pick up a differnece between the motors with the laser, and since the temp moves so quickly, my thought is that there must be air pockets floating around in that motor. It's been doing this for the last 20 hours or so; I sort of gave up chasing it since the motor didn't show hot on the laser and even the gauge reads normal at cruise.

BTW - I've dug around with no luck as have 2 other mechanics... I guess now it's time to throw it out to the board.

Ed Donnelly
08-25-2007, 07:50 PM
Check your grounds.. My Pantera (car) did the same thing. The temp would shoot up 40-50 degrees in seconds.. Mech. said it was impossible. Found the ground from the battery to the frame corroded. Cleaned up the connections and the temp problem went away.....Started faster too.......Ed