Robert Lewis

New DeWitt's aluminum radiator, new Vintage Air, new hoses, and second new 180* thermostat, yet on a hot 94* day at 65mph light-load cruise, my '65 327/365 gets to halfway between 180* and 240* in minutes. Vintage Air sent me a puller SPAL fan instead of a pusher (one of many product defects, but that's another story), so that's disconnected, but I still don't think it's the cause of the problem. The original non-air fan and clutch appear to be working.

What else should I be trying? I'd suggest the water pump, but don't they usually work unless they are leaking?

Gary's '66

Have you re-checked your water level? You may have had air in the system. I always fill through the thermostat housing then top off at the expansion tank.

Robert Lewis

System is full of new "green" antifreeze. I've topped off as you do.

What kind of readings should I be getting?

CaveCreekChump

Step one: be sure you can rely on the accuracy of the gauge reading.

Is it really running that hot? Has the gauge always been accurate? Have you been using a sending unit that works well with your gauge?

I would shoot a fully warmed up engine with an IR gun to check the actual water temps. If that testing shows that the engine is running significantly cooler than the gauge is reading, get thee to Auto Zone and buy a Duralast TU5 sending unit.

If the gauge is accurate and the engine is running hot, have a cocktail and proceed to Plan B.

Gary's '66

To check circulation feel the bottom radiator hose (after T stat opens) to see if its getting warm.
If you have an IR gun then first and foremost you need to check to see if your gauge is even correct. If you don't then get one, they're CHEAP at Harbor Freight.

So, assuming you have one, point it at the top hose about 6" away from thermo housing and same distance from the hose then compare that reading to what your gauge shows. If, after you've confirmed car is in fact running hot, recheck your timing (I'm referring to your "jumping a tooth" thread) as it may be too far advanced or retarded which can cause overheating.

One last thing, running two fans can actually impede air flow at high speed.

Gary

buns

So that's roughly 210°. That's not terribly high. In 1966 they finally put a red line on the gauge and it's at 250°.

Usafstingray

My L76 has been running hot as well. Not sure what sender is in it, but it reads halfway between 180 and 240 while the manifold is 176 on the temp gun. I had no issues with overheating at speed, but did have problems in traffic idling. Since I have a driver not a show car, I went with a 160 thermostat and a 14 inch electric fan with a separate 180 thermostat...the derale kit. I don't have a new radiator and I'm running a standard water pump. The temp is steady in traffic now and at high speeds still. Problem solved for $50...for now. Perhaps a new radiator is in my future and I've heard that water wetter helps a little. The motor is my own fresh rebuild - was able rule out any flow issues.

Powershift

The factory air cars also had sealing strips on the top and bottom of the radiator to make sure all the air went thru the radiator and not around it. Also a lower radiator shroud and a larger diameter fan. I would install these if you have not already done so.

Besides verifying the actual temp with an IR gun, I would also check the distributor vacuum advance to make certain it is correct and working, and that my thermostat is a 180 degree unit. Coolant should be a 50/50 mix with water. Higher concentrations can affect cooling (slightly).

Larry

Jakes64

As others have said, check with a IR gun. Is it overheating at idle or just at cruise? You said the SPAL fan was disconnected but was it removed? Could it be restricting air flow thru the radiator at cruise?

Mr D.

Don't forget to check ignition timing and if there is any doubt about anything than start from ground zero and re-time your engine.

BTW; to me ground zero is pulling the #1 plug and finding true TDC and go from there.

Robert Lewis

So how do you find true TDC by pulling the #1 plug? I should add that I have no help: if it can't get done singlehandedly, it can't get done.

Gary's '66

Maybe if you fill in some of your personal info, like where the he!! you live, someone might be willing to lend you a hand (pun intended).

Gary

buns

Robert Lewis

You're right. Done and done.

Anybody want to visit the beach for a weekend - or a day, or whatever?

Mr D.

This is something you can do by yourself and there is a ton of info on this subject on YouTube.

Once you know where TDC is you can then start the process of making sure your timing is correct and the vacuum advance is working correctly.

Boyan

Please post what numbers are stamped in your vac advance can.

CaveCreekChump

Al uses the term "go ahead" exactly 10 times in the last half of this video.

Fascinating.

Robert Lewis

Advance can is a B28, which should be correct for a '65 327/365.

Mr D.

Robert

Go out to http://lbfun.com/Corvette/Tech/vettetech.html and read everything on cooling and ignition.

Dennis