Overheating of straight 6 & 8 engines

Posted by fredkanter On 2016/12/28 14:33:42

There's been volumes written on the subject with the usual obvious remedies. Some include oversize or aluminum radiators or electric radiator fans. I began to think, hey these cars ran well back in the day with factory radiators and belt driven fans, so what has changed??

Having disassembled two 51-54 327 engines and pressure washed the water passages from the water passages on top of then block I found an enormous amount of rust/crud coming out. Then to be doubly sure I removed the block core plugs and found about 1 to 1 1/2" of crud in the rearmost core plug.

What has changed is the effects of time. When a car is 2 or 10 years old vs. now when a car is 65 years old there's been much more time to rust and settle. When the crud settles it creates a hot spot which can result in localized boiling even though the temp gauge reads just a bit high. When the car is turned off and water is not circulating the boiling can release the pressure cap and thus "boil over".

If you encounter this situation and the usual fan belt/thermostat/backflush cures do not work try removing the rear core plug and let us know what you find. Stick your finger down into the water jacket. it's over 1" deep at that point. I used coat hanger wire to loosen it in all 5 core plugs.

Thoughts??