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Jerry
Jerry, Master Mechanic
Category: Car
Satisfied Customers: 17220
Experience:  ASE master, 30+ years. All makes and models. Trouble shooter, shop forman, service manager
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Sub: Abnormal Engine Overheat Conditions "Mornin Doc," Beyond

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Sub: Abnormal Engine Overheat Conditions
"Mornin Doc,"
Beyond a defective thermostat, what would cause a rebuilt engine to basically peg out on temp readings @ idle on a friend's PV especially engine shut down?

Okay, engine indication "normal" when driving, even when at 70 MPH and sustained for example, an hour. I drove the PV a little myself and it scoots very nicely and the engine hums.

Problem:
- When the engine is turned off, the temp reading goes full peg to hot. Climbs from 1/4 heat immediately at shut down, climbs to off scale full hot almost immediately again when the engine is turned off? Had to raise the hood & let the engine cool off, took almost an hour (time till return to 1/4 heat indication on gage).
- Engine - B-1800 (same as my p1800)
- Compression, timing, dwell . . . fuel etc all good to go
- Less than ~ 300 miles on rebuilt engine!
- Oh yeah, the water pump. and a new (refurbished radiator) already replaced.
Bill

Hello and welcome, Super mechanic here. Thank you for trusting us with your concern. I will do my best to help you with your question.

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Unfortunately, it sounds like you may have a blown head gasket and you’ll likely need to take it in to get it repaired or at least do the test yourself.

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About your friend's vehicle.

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The first thing that you want to do is check the cooling system for any exhaust gases. There is a tester for that, that you can gt from Autozone for about $20. It comes with instructions, but there is a blue fluid that is used in it, if the fluid turns yellow, that is exhaust gases.

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Block tester available as:

Napa BK.(NNN) NNN-NNNN/span>

OEM/Block Tester AUTOZONE

Part Number:
27145

http://www.autozone.com/autozone/accessories/Tools/Block-Tester/_/N-25dh?filterByKeyWord=block+tester&fromString=search

If there are any exhaust gases in the cooling system, that will cause more pressure than desired and will allow the engine to burn coolant and/or heat the coolant up too high. Most times not filling the crankcase with coolant either.

If there are, then there would be an internal engine problem, like a head gasket or head.

Of course, you will want to make sure that the system is full, the coolant is circulating,as well as the pressure cap holding pressure. Thanks

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