53 Roadmaster 76C running hot going up inclines

[Brian Noubarian]

This car runs hot. It’s okay on a 70 degree day driving on level ground (temp gauge registers about 65% of way up the “normal range”), but as soon as you hit a hill, at any speed, temp quickly goes to 85-90% of normal range (right side of the “N”) and if its hotter out, it will go all the way to 100% of the very outer range of “normal” very quickly. I typically shut it off at that point as I suspect it will keep getting hotter and fully overheat. Guage is working correctly as you can tell the engine is very hot. When you start down a hill the temp goes back down to 65%. Idling is no problem.

The car has been through a complete frame off restoration. Engine has been rebuilt including a rebuilt water pump and re cored radiator, new hoses, rebuilt carb., etc. I just put in a new thermostat too since that was easy to cross off the list. Car has about 700 miles on it since restoration was completed 5 years ago.

This is my first 50s car, but I am sure it should not be running this hot. Fan appears to be correct and radiator appears to be correct and proper 2” thickness. Running water / coolant mix and my mechanic adding a “Water Wetter” product. No change. Tune-up was just done so I think timing is okay.

Anybody have similar experience or ideas? I was told getting the fan closer to the Radiator would help and/or getting a 5 blade fan (has correct 4-blade currently). Even told going all water would help. Not sure what to try next, any ideas?

Thanks, Brian

[Aaron65]

Has the radiator ben boiled out? Thermostat installed in proper direction???

[Fr. Buick]

These things have a HUGH radiator, so cooling should not be a problem except for a very steep climb on a hot day.

I agree with taking out the radiator for a good cleaning.

Also look into a radiator filter. These are made to be placed in the middle of the top hose with a mesh screen to catch rust and debris, a common problem after a rebuilt engine.

Google search "Russ Martin Nailhead" and ask him where to buy. He is a great mechanic and knows his Nailheads in case your problem continues.

Have fun with a cool car,

[Brian Noubarian]

Yes on Thermostat but not sure on Radiator. Will look into that. Thanks, Brian

[Brian Noubarian]

Thanks. I'll give that a try.

[NTX5467]

Possibility that the fan might be facing the wrong direction, with respect to "pitch"? Blowing toward the radiator rather than toward the engine, for example. Might sound funny, but it's happened.

Fresh tune-up, but is the vacuum advance working? Correct timing, too? Retarded timing can lead to an overheating situation, sometimes.

What about transmission issues?? "Slip" builds heat.

In reality, I suspect it's a radiator flow issue. The radiator might look great looking through the filler cap, but can be seriously clogged on the bottom side of the core. The "working harder" engine will build a little additional heat than when in a flat-land cruise situation, but if the radiator's doing its full job, the additional heat would be dissipated with little increase in coolant temperature.

I guess, after they hot-tanked the engine during the rebuild, they took pains to flush out the cooling system water jackets, especially the passenger side rear area, with high pressure water????

Just some thoughts,

NTX5467