Can't Cool It Down

[Bob Carroll]

I have a 63 Coupe with a 327 (carb, no air,no ps/no pb) and the engine keeps running hot. To date, I've replaced the heater core, radiator, thermostat, expansion tank, hoses along with new antifreeze. The waterpump is the last part left and then I'm out of tricks. Within a few minutes of running it's up at 220. Hasn't been on the open road yet. It's winter here in NJ and this doesn't seem right. Anyone have any suggestion?

[Albert P.]

Re: Can't Cool It Down

First verify that the gauge is correct;check radiator connection to intake manifold with IR temp gun;fan clutch working?

[Jim T.]

Re: Can't Cool It Down

Do you have an operational vacuum advance connected to the proper vacuum source which supplies vacuum to the vacuum advance 100% of the time the engine is running?

[Terry D.]

Re: Can't Cool It Down

Bob

Check the archives, there are many posts about over heating and the proper timing for these engines. A bad vacumn advance can wreck havoc with temperature
Terry

[Bob Carroll]

Re: Can't Cool It Down

It also has a waterpump bypass. I'm not sure if this is correct for a stock 327-340hp. I tought this used just for fuelies and high flow pumps. I want the car to be correct.

[Duke W.]

Re: Can't Cool It Down

Yes the 340 HP engine has the external bypass, but whether it's there or not has nothing to do with overheating.

As stated verify the temp gage readings with IR gun readings on the radiator outlet hose. Also check the radiator inlet hose to determine the temp drop through the radiator.

The original VAC (stamped 201-15) is not suited to the idle vacuum characteristics of this engine. Even if it works, replace it with a NAPA VC1810 or equivalent.

Look at the radiator and determine if it is a correct Harrison "316" and the date code. Aftermarket brass "bolt-in" replacements don't have near the heat transfer capacity as the orignal aluminum type, and over decades the tubes of any radiator develop deposits, which vastly reduce heat transfer capacity.

Duke

[John O.]

Re: Can't Cool It Down

Hi Bob

Had the same problem with my 62 after my complete restoration. Gage kept reading 200 plus degrees but engine never overheated. After doing a complete check and asking opinions here, it turned out to be a faulty sending unit. I bought one at Napa and now all is fine. So if you are not losing antifreeze and only your gage is reading hot, check sending unit.

Good luck...John

[Chuck R.]

Re: Can't Cool It Down

After following through on the possible remedies already listed, other than the water pump as you described, if the engine still over heats, you may have blocked passages along the cylinder walls.

To verify this, it would require popping a freeze plug and running a coat hanger into the passage seeing if you get significant rust scale or sludge.

Chuck

[Chuck R.]

Re: A question for the group

Would improperly installed head gaskets also cause this issue?

Just curious,

Chuck

[Jim T.]

Re: Can't Cool It Down

Removal of the drain plugs on the side of the block will also allow drainage of rust/sediment.