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So I have my WC 53 on the road. But I have an unusual overheating issue.

The engine has been rebuilt, ground crankshaft, new pistons, rings, bearings and valves. New waterpump and distribution tube.

On startup and driving the temp rises to 180 degrees F. On 1st real engine load up the temp rises to up to 220F then suddenly drops to 140 to 160 and then climbs back to 180. "Seems" to stablize at that but the needle jumps up and down +/- 20F. Then at the next engine load up the temp can rise up to 220/240F and again drops back. Almost as though the thermostat is sticking but I replaced the thermostat with new 2 weeks ago and no change. I drilled a small hole in the thermostat to let the air bleed out, also the bypass bleed in the thermostat housing is clear. The temp gauge is the original and "seems" to be fine.
Thoughts appreciated.

Cheers

Ian J

It's fine Ian. The gauge and instrument readouts were as accurate as they could mass produce cheaply eighty years ago. As long as the thermostat doesn't stick shut you're good.

Sure sounds like a thermostat issue to me. I know others will say "don't do it", but I'd take the thermostat out completely and see what it does. I am not suggesting leaving it that way, but just as a test to see if the gauge stays at one point rather than going up and down.

Is the radiator in good condition?

So yesterday I reverse flushed the engine and radiator. In doing so I checked the radiator flow, all good.

I then tested the thermostat and found it was slow to open. I replaced it and will test when I get time. The reality is I didn't find anything that would account for the symptoms.

Next attack is to try another temp gauge as its possibly a faulty one.

I will also try removing the thermostat if all else fails.

Thanks for the advice.

Ian

if its all stock WC53 cooling system it would blow water out the radiator cap if it got that hot for very long. or maybe it was popping open right before that.

Hi Kaegi,
That was very much my thinking as well, yes it's all stock WC 53.

I have a new Caterpillar capillary tube gauge so I am going to install that and see what I get.

What symptoms would you expect from a blocked or rotten water distribution tube?

I did replace it but the engine did not run for about 5 years after rebuilding save for a regular wind over with plugs out to keep the oil circulating.

Cheers
Ian

I have never had one blocked. had a few engines with lots of sediment in the lower few inches of the water jackets aorund the cylinders but mopar starting in mid 30s through problaby even now all have water jackets full length of the cylinder plus some. one reason they take forever to warm up in the winter. cold blooded beasts. that sediment build up never caused any overheating issues for me.

chevies don't have full length hence they wear rings out and smoke. ;/)

Hi Kaegi,
Certainly the WC'S have a reputation here for never overheating. I am on the path of faulty temp gauge so next weekend will be the test.
Cheers
Ian

Hello I had an overheating problem with a 47 1/2 ton pickup I own it would run at 200+- degrees but not really overheat never really went far with it thinking it had a possible bad reading gauge one day I took it out East for a run about 2 1/2 hour ride doing 40-45 mph had plenty of time to think and as the temp started to reach 200 I thought about what I learned from my boss a Ww2 vet motor pool Sargent that I worked for while in high school he taught me to time a car by ear and always said if she’s running to late she’ll run hot.so it popped in my head that day and I pulled over on the side of the road left it running advanced the distributor very slowly till she sounded smooth shut the hood got back on the same road drove another 1hr the temp dropped to 160 and the truck ran much better .i think that’s one reason I like the old trucks their not fast but they give you plenty of time to think.

Hi Tom,
I also wonderd about engine tune so have chacked and rechecked timing dwell etc, no change.

I power flushed both engine and radiator, certainly some crud but no more the one would expect of a 70+ year old vehicle. I changed over to a 170 degree thermostat, still no change. I'm thinking radiator out and a thorough clean is in order.
Sigh!

Ian

Ian, could be your problem I would flush it in the truck by taking the radiator hoses off and cap and blocking the lower hose filling the radiator with water and then adding a little compressed air to the lower hose outlet and see what comes out the top
Keep it up till it’s clear

Hi Tom,
Alas I have already done that, lots of discolored water but nothing to indicate a problem.
I'm standing beside the truck now with the engine at 180f with Prestone radiator flush going around. I tested the temp gauge against my digital thermometer and its 100% accurate. Clearly a problem, now it's about diagnosis.

Thanks for the ongoing input, really appreciated.

Ian

Well I finally bit the bullet and pulled the radiator out. Further road tests showed that the temperature rose when under full load and quickly dropped back once the load was removed. That is, it was fine on the flat at cruise speed, but under full throttle acceleration, especially up steep hills, the temp would rise. So far as I can ascertain there is a partial blockage in the radiator (well a number of tubes) limiting the water flow to the point that it would overheat under load but cool quickly when no load.

The radiator is at the shop.

Cheers

Ian

nd now the radiator is back in the vehicle, and there is NO BLOODY change in the problem. I really am stumped!

I have installed an alternative temp gauge, pulled the gallery plug from the cylinder head above the temp gauge bulb and the gallery is completely clear as is the cylinder block gallery just above the starter motor. My point being the water jacket "SEEMS" to be completely clear.

I checked the distributor number against the master parts list and its correct. Timing is 4 degrees BTDC with 91 octane gas.

GO FIGURE!

Ian