Today's Observations
 

Took my 1936 for a ride today for the first time as new owner. Watching oil and temp gauge closely. When I first started the car oil was about 20-25 psi, left driveway temp was half way up. Temp remained at 1/2 the first 2 miles then all of a sudden shot to the top then came back down to 1/2. While idling for a few minutes oil pressure was at 15 psi and temp went all the way up again. Came home car was hot but not overheating. Keep in mind supposedly there are no thermostats installed. Does this all sound strange or should I not worry?

I proceeded to change the oil, refilled with 4 1/2 quart I was over the full line on the stick, I thought this car took 5 quarts. Previous owner was running 10W-30 full synthetic, not crazy about that idea but he was running it for six years that way, not sure I would change now. I might run 10W-40 though

Re: Today's Observations
 

Some use 10W-30 (I do) and others maybe 5w-50. I get 70 psi cold and about 15 hot. Temp variation: My OE passenger side temp sensor does that (have a mechanical sensor on left) so maybe its that, or you actually have stats and one is sticking. Can you try an aftermarket sensor/guage ?

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The oil dipstick marking is often not correct, you need to add 5qt of oil and then remark the stick to match. Why was the car not running thermostats, any idea?

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You won't know until you open it up, but there exists some possibility that sludge in the engine is taking up significant volume which could explain the quantity reading being high.

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As far as the thermostats I'm just going on what the previous owner told me, I have not opened it yet as the therms go in the top hoses as I understand and it looks like it might be a pain the butt. Also they seem to be hard to find and not cheap.

I took the car for a second drive, now keep in mind its about 45 degrees here in Boston. The temp gauge went up and down, any time I sat for a few minutes she went up to the top, then as I drove it was mid range most the time. But after I drove a few miles I put her back in the barn, temp gauge was at 3/4 but I could here the coolant boiling and she spit out a little antifreeze from under the radiator cap. Something isn't right.

Re: Today's Observations
 

For the flathead to run efficiently, it needs thermostats for at least 160 degrees (stock), but preferably higher. I run 170; many recommend 180.

That said, I would leave the thermostats out until your basic cooling problem is resolved.
First, check the obvious
- Coolant in the radiator about half inch above the core.
- Hoses not soft, kinked, or collapsed.
- Correct fan installed and working
- Distributor timing adjustment advanced, certainly not retarded.

Next, investigate the coolant in the radiator.
- No more than 50/50 antifreeze; preferably less, like protection to zero degrees, not minus 30 degrees
- test for products-of-combustion in the coolant, indicating a head gasket leak
- Watch the water flow into the top tank is vigorous at idle.

If all of that checks out okay, suspect the radiator.
- Are all the fins straight, or a lot of them laid over.
- Drain down the coolant to just empty the top tank; do the tops of the coolant tubes look crudded over? Do some of the tubes not drain down? If either is true, you can try flushing the cooling system with a good flush product, but the radiator will probably need to go to an old-school radiator shop for cleaning ($$) and repair, or re-core ($$$).

Maybe report what you find.

Re: Today's Observations
 

Hey thanks for all that. I do have a very minor head gasket leak on one cylinder, a few drops of anti freeze sits in the valve indentation under the valve. I used K-seal and it just about stopped it. "But" maybe the K-seal did more than just slow the leak, maybe it clogged up the radiator. I called the company they said it would not do that. I looked under the car and she was spitting anti freeze as I drove because its on the battery box hanging under the floor. Next time I run it I will look at the circulation before it gets too hot, thanks

Re: Today's Observations
 

Maybe, temporarily at least, hang a cheap plastic bottle off the end of your overflow tube and see how much coolant is being pushed out while driving. On my 36, if the coolant is right at the top of the tubes it will push a bit out when it is driven. Let the radiator find it's level. If the Battery box under the floor is wet with coolant after a drive, it may be leaking elsewhere, I can't imagine losing enough to get the battery box wet considering the overflow is on the front side of the radiator

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Also, think about purchasing an infrared thermometer. (the kind everyone is using to check your temperature to make sure your not covid) They are available at Harbor Freight.
You can use that to find "hot" spots on the engine and radiator.
It has helped me figure out when a thermostat wasnt working.

Re: Today's Observations
 

If after some driving it is still spitting out anti-freeze, then you'll need to pull the heads and determine what the cause is. Could be a blown head gasket, could be a problem (hate to say it, but a crack) with the block.

Keep in mind, that if you don't do that, then you can get water in the cylinder - rusting the bore, ruining the rings, etc.. Water in the cylinders is not good . . . even a small amount.

Best of luck!

Re: Today's Observations
 

The antifreeze on the battery box is from the radiator cap boiling over I assume, because there was also a little antifreeze on the left fender and left hood vents. Today I'm going to flush the system and also will buy one of those digital thermometers. I was going to buy one before as mentioned by someone else but I could not find the temperature range specs. I was surprised a thermometer designed to take human temp would go as high as 200 degrees, is this true?

Most likely I will be pulling the radiator and having it re-cored. As far as I can tell there is no radiator replacement available for this car as mine has the indent under the tank for the fan. At some point I will need to know which thermostats to buy as I see there are several types for this year.

Re: Today's Observations
 

Brassworks should be able to provide a radiator, but I would consider the recore first.

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This morning I drained the radiator and put fresh water in flushed it a little, damn it holds a lot, what is the coolant capacity? It didn't look bad but you could see the remnants of the K-seal. I took her for a ride maybe 6 miles, the temp stayed right at 1/2 the whole time. When I got home I was able to remove the radiator cap (not too hot) and saw the water was circulating nicely. Now what do you think is going on? I plan to flush it again once or twice before adding antifreeze.

And how can I tell if there are thermostats installed with out removing the hoses? What do they look like on a 1936 twenty one stud?

Re: Today's Observations
 

IF you plan on draining the "current" water that is in it now for more flushing, remove ONE of the upper radiator hose...... at the point you drain the "current" water and you will KNOW for sure IF they are present!!! ALSO it may be "prudent" to go ahead and get you a set to install at that same point IF they ARE missing!!!! JMO

Re: Today's Observations
 

I was wondering if you could feel it in the hose if you squeeze it. I'm not sure what these look like or where they exactly go.

Re: Today's Observations
 

IF your hoses are supple enough you "might" be able to feel around the bottom of the upper hose where in goes into the water pump and squeeze enough to feel it BUT IT is entirely possible doing such "could" disrupt its position and then you might have to remove the hose to fix it!!! You might be able to just remove the top of the hose at the radiator inlet and look down inside and you would also be able to see the thermostats in there!!!!

Re: Today's Observations
 

Though not exactly for a Flathead, the look is almost exactly the same. Here is a "general" look of a thermostat. It is pictures as it would sit in the hose/water pump outlet!!!! I.E. as you look inside the hose you "should" see the triangle pointed part of the thermostat.

Re: Today's Observations
 

The cooling system capacity of the 1936 Ford passenger car is 22 quarts. Ref.: Ford V-8 Service Bulletins, page 330.

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If you have stats the top hoses will be cold until they open. Probably won't open at the exact same time.

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Flushed the radiator a second time and took her for about a 10 mile drive, she ran right at the 1/2 point on the gauge the whole time, a little higher when I stopped for a few minutes. I only cruise at about 35 - 40 mph max, don't have the best brakes. What ever seems like the over heating went away after the flushing. I'm wondering if the K-seal made it overheat??? Anyways on going project, still need to figure out the therms, inferred thermometer is coming tomorrow. Seems 1936 therm is an odd ball, hard to find.