327/340 engine overheat

[Bob Fellows #37468]

My 1963 Corvette with a 327/340 solid lifters seems to be running real hot.
Temp indicator is reading almoust full scale.
After this the engine seems to run rough.
Is this safe to drive?
Should I take the thermostart out?
Valves and timing are as required by the book.
Need help.
Thanks,
Bob Fellows

[Tom H.]

Re: 327/340 engine overheat

I would say it is not safe to drive until you check it out. I'd start with the basics. Water level and coolant mix to specs ? Radiator in good condition ?? Are you confident the guage is correct ?? Have you made any recent repairs or adjustments that may be causing this, such as a timing adjustment ??

[Wayne P.]

Re: 327/340 engine overheat

To add to Tom's comments. Check the proper operation of the fan clutch and the vacuum advance. Do you have an aluminum radiator? If not, you probably will in the near future.

[Gary Schisler]

Re: 327/340 engine overheat

Lots of info in the archives. I would do a search and then sit down and read for a while. The gist of the material is as was described above especially checking the actual temperature with an IR gun aimed at the upper hose. You can also take readings at various levels on the radiator. If the rad is original, it may be the culprit but you want to eliminate all of the other possibilities before you spend big $$$ on a repro radiator.

[Verle R.]

Re: 327/340 engine overheat

Bob,

Lets start at the beginning....

Removing the thermostat will not solve an overheating problem unless it is stuck closed.

Is it boiling over? Coolant on the ground?

What are the circumstances?
Outside temperature?
Stop and go or highway?
7500 RPM shifts?

As suggested before, check coolant level.
Check condition of radiator hoses, especially lower.

Verify engine temperature with another device, such as an infrared temperature gun or mechanical temperature gauge.

Check the wiring from the temperature sending unit to the gauge to make sure it is not frayed/grounding.

Verle

[Timothy B.]

Re: 327/340 engine overheat

Bob,

If the car still has the original vacuum advance #201 and you replace it with #236 or it's current NAPA crossover 0@4"-15@8" (1810 or B28 double check #) I think the car will operate much cooler. Also check heat riser valve for proper operation.