Engine: 1950 Champion Engine Runs Hot

[Blu Stu]

Hello Studeland,

Having a problem with my 1950 Champion's flat-head running hot. As soon as I top out at 65-70 mph, the engine starts running on the hot side. The temperature gauge's needle leans at the far end towards "H" and stays there until I start slowing down. I've had the thermostat replaced but can't figure what else is going on that would make the engine run hot.

Was wondering if maybe the overdrive wasn't kicking in as it should when triggered but I wouldn't think I could get it up to 65 MPH if that were the case. Engine runs fine at those speeds, i.e., it doesn't complain but it gets hot. Afterwards the car is hard to start if I park of a bit and then start it. Got no clues as to what's going on.

Any thoughts on other potential problem sources? Please let me know, thanks.

[Noxnabaker]

if someone's been using the car with only water for cooling the blades on the waterpump could be rusted away, I experienced that with a -66 Rambler Ambassador once (since I'm living in Sweden it wasn't noticed until springtime), otherwise I'd remove the frost-plugs & take a look, I just did that with my Mopar s.b. 'cause there was some leakage on one of the rear ones & you should've seem the inside... thick! with rust-sludge.
But for a start (if you haven't already done it) I'd flush the whole complete system (even the heater if you have one), take of all the hoses & flush the radiator & engine separately.

[BobGlasscock]

You might want to check the radiator core to be sure it is clean and open.

[Noxnabaker]

...& the starting-after-recently-stopping-problem could be caused by "gas-vacum-lock" in the carb since it's so hot.
A good thing to do in any case to prevent that is to get a piece of bakelite (the "plastic" stuff before plastic) or aluminum 'bout a half inch thick to put between the carb & manifold.

[Bud]

There are several things that will cause your engine to run hot. A radiator or block that is partially plugged with rust and crud, lean fuel mixture, defective thermostat, retarded spark due to incorrectly set timing or a worn or sticking centrifugal advance or defective vacuum advance along with a leaking head gasket or cracked head or block will cause overheating. Even a slipping belt can cause your problem. Bud

[Chipmaker]

I had the lower radiator hose get sucked flat and cause this.It only happened at speed and was a old hose.

[Blu Stu]

Hello All, thank you for your responses. I forgot to mention in my first post that in addition to replacing the thermostat, I also had the radiatior replaced with all hoses, and there are no issues with the cooling fan. That's why I'm so perplexed.

Bud, as far as as a retarded spark due to incorrectly set timing or a worn or sticking centrifugal advance or defective vacuum advance along with a leaking head gasket or cracked head or block will cause overheating, it's hard to say, since the engine runs fine. No hickups or anything. When driving the Stude around town the temp gauge sits in the middile but when I take it on the highway after about five minutes the temperature starts climbing.


Nox, regarding the "gas-vacum-lock" solution, will keep that in mind. I'm thinking though, that you may be on to something with the frost-plug look-see. Radiator, hoses, and cooling fan all problem-free. So maybe I'll check out the frost-plugs, don't know what other road to take.

Thanks again All and if you can think of any other pointers, would much appreciate it. Take care.