Another Cause of Engine Overheating!

timber21 · Post by **timber21** » Sat Oct 27, 2018 5:57 pm

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Post by **wesk** » Sat Oct 27, 2018 6:09 pm

How did the failure of the transistorized voltage regulator cause your engine to overheat?

OKCM38CDN · Post by **OKCM38CDN** » Sat Oct 27, 2018 9:31 pm

Maybe the gauges went wild and said it overheated...

timber21 · Post by **timber21** » Sun Oct 28, 2018 6:10 am

Returning from a 50 mile trip, first heard belts squeaking momentarily and then noticed the voltmeter pegged out and temp was rising; took the next exit which was about a couple of miles down and the radiator was already boiling and releasing pressure. One almost new belt was already in pieces and the second was hot. Towed the jeep home and replaced the voltage regulator with an old mechanical one, hard time starting but voltmeter was within the normal range now. Checked the plugs, no 3 was clean with no residue; did a compression test and no 3 was significantly lower than the rest. Bore scoped no. 3 and it was shiny clean, so pulled the head and sure the head gasket was blown. While the head was removed, replaced the valves and springs, devised a tool using Harbor Freight hydraulic hole punch to replace the guides, and finally replaced the rings and rod bearings, and honed the cylinders. Jeep is back in service with good compression on all 4, and everything is fine and has already attended two events involving similar trips/distance. The mechanical voltage regulator's plugs were badly corroded with one broken key, so I decided to use the plugs from the transistorized unit that I had removed and that's when I opened the unit and noticed the internal damage to the regulator. I do have a RT-68 unit on the jeep but it is almost never turned on.

Post by **wesk** » Sun Oct 28, 2018 9:17 am

That's a lot of work. But it looks like you have a handle on it. I bet the next time your belts start squealing you'll pull over and lift the hood before the temp gauge even starts to rise! With all that dragging of 25 amp generator I would have suspected some generator damage. Especially overheated armature wraps.

timber21 · Post by **timber21** » Sun Oct 28, 2018 10:07 am

I expected problems with the generator, but it passed all the field tests, so, I left it alone. It was one of those unintended projects that you think it would be done in a few hours and then when the head is removed plans change.