1936 Overheating Problem

[AnthonyG]

Just hi-lighting a few of the obvious. With no rebuilds or radiator replacement or reconditioning & normal aging with minimal maintenance ur engine & cooling systems are more than likely loaded with rust. Only very occasionally a find with a car having exceptional owners it’s whole life who we’re fastidious about regular frequent flushings & antifreeze changes. With this & your description at the least you need to do a few thing to insure your not gonna be chasing ghosts for another decade!
-Send the radiator out & have all checked & serviced & Probly r-cored.
-As said if heads & radiator are not aluminum a stronger caustic soda flush will loosen a lot
more rust & crud.
-Install hi-flow pumps
-Being a purist is good but to enjoy & drive the expansion tank, a pressure cap & a 4lb release valve on overflow tube will help the tank work.
-As said make sure your timing is correct.
-If all this doesn’t help ( it will) it all needed doing to give you a good base line. But if overheating still exists albeit less & I know this makes purist’s crazy, go with a strong electric fan. On ‘35-‘36 a push fan is easily hidden behind grille in front of radiator. A DIY shroud really helps as well!
If you don’t want to do the Fan, shroud & overflow tank & overheating is still there albeit improved you’ll need to live with it or pull engine & send block out to be hot tanked & professionally cleaned then refresh / rebuild as required.
I’ve been their & chased the ghosts for 5 years & know how frustrating it can be.
JMHO, truly wish you the Best in resolving!

[38 coupe]

I have a friend with a low mile 36 that we got running well. However, it would overheat. He had the radiator cleaned. He filled the engine water passages with dilute phosphoric acid, then flushed with baking soda solution. He got lots of rusty crap out with that trick. After all that work the car would run nice and cool at idle even in south Texas temperatures. However, it still got boiling hot if driven at normal speeds for more than a mile or two. Finally he installed Skip's higher flow water pumps and that seems to have solved the heating while driving problem.
You can have a flathead that cools at idle and down the road, but ever passage needs to be clean and your water pumps need to flow a lot.

[Jacques1960]

Really great thread which I’m following with considerable interest. My 36 Phaeton also runs hot, but not to the point of boil over, just occasional vapor lock. Prior to pulling pumps for rebuild, I removed lower radiator shroud to see if additional air flow (if any) would make a difference. Appeared to be negligible. Laser showed 155-160 on top hoses, 135-140 on bottom, so gauge itself clearly not a good indicator of temp (gauge always 3/4 to high “normal”). Will try adding diesel to non-ethanol fuel at next fill up.

[Robert/Texas]

My ’34 roadster was in barely running condition when I bought it in 1994. Among other things the previous owner told me was that it overheated. The radiator had rusty fins. The problems with the ‘36LB engine were with the carburetor and distributor. I replaced the Stromberg 94 style carburetor with a Stromberg 97 and the distributor with a Mallory one. The engine ran great after this and has never overheated since. It can sit and idle for an hour or two and not overheat. I think that the previous owner’s problem was probably a timing issue.

Since then, the Mallory distributor wore out and has been replaced with the original one that came with the car. This distributor was rebuilt by Charlie Schwendler and the car has never run better.

Robert

[Jacques1960]

Will be sure to look into the timing aspect ����

[Flathead Fever]

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First off, excellent description of the problem and what you have tried so far. I wish everybody described their automotive problems like you do. I was fleet mechanic and the more details from the drivers the better. By the time I was ready to retire I was in-charge of 157 vehicles, all by myself, nobody in the shop but me working late nights. Nobody in the yard to talk to but opossum that lived in the yard. All repairs and service including smog inspections were done in house. Aerial booms, big air brake trucks, cars, generators.... 100% of all work done inhouse unless it was under warranty or engine machine work. I did not have all night to be driving around trying to re-create some weird problem. The more info that helped me recreate the problem the better

Usually if an engine overheats at idle but is okay going down the road it's a lack of airflow at idle. If the temperature is okay at idle but it overheats while climbing a little grade it's radiator problem. That is how I use to determine if it was a slipping fan clutch or a plugged radiator. There is hill in San Bernadino, CA right next to the phone company yard called Little Mountain. It has a steep, a mile long road going up it to the crest and then a steep road down the other side. That was my radiator and engine misfire test track. If the temp slowly climbed as I drove up the hill, I knew the radiator was plugged. I went up to Lake Arrowhead one time and brought the snowplow down the hill for service. Just a one-ton pickup, almost brand new, with a snowplow blade on the front. Later that night when I went to take it back up, I didn't get a mile up that mountain and it started to get hot. That snowplow blade was defecting the air from going through the radiator. I turned around and went back to the shop, took off the blade and loaded it into the bed with the forklift and went back up the mountain. No more heating problem. That was interesting lesson in airflow through a radiator. 50 mph and no air was getting to the radiator.

A couple thing you can try is to put a fan in front of the radiator at idle and see if that brings the temp down. You can also take your infrared temp gun and aim it at the tubes and see if you have ones that are colder than others. That will tell you if they are plugged. If an electric fan will fit, hidden between '36 grille and radiator, might help a lot at idle. When that fan kicks in the temp will fall like a rock. I'm not a fan of electric fans, alternators... on original cars but they do solve cooling problems.

The thing is, you know the car was drivable when it was new. If flatheads all overheated a bad as some people think there would not be a useable block left. And if the brakes were as bad as some people will tell you there should not be any grille shells left.

I talked to a guy, his dad bought a new '32 BB truck and then had second rear axle added to haul even more weight. He hauled produce from the scorching hot, low desert, here in CA up over the steep grade of the Cajon Pass and into the high desert. So I asked the guy, "did it ever over heat"? And he said, "No, but it did break a rear axle once because we over loaded it." He also told me a neat story about his brother working on a a brick building for Henry Ford. He said before the workers would arrive in the morning Henry Ford would show up and pick through the bricks and remove any chipped ones. That doesn't sound like a guy that would stand for a vehicle with his name on it overheating. "If" there are people out there that have '36 Fords that will idle all day log and not overheat than the problem is not the'36 Ford. There is something wrong with yours. I had an older amateur restoration '36 chassis with a '37 21 stud I bought for $2500.00 to get the drivetrain that would idle all day long and not get hot. I was impressed with that engine. That engine is going in my '34 BB Truck. It's not the correct '34 engine but at least it' a 21 stud (my first) and the price was right. The '39 trans, 36 rear end and hydraulic brakes are stored away for a future hot rod project. The frame and radiator got sold.

I don't think the overheating problems are because of a bad design, I think problem is they are just old. I'm not functioning that well either but I know that at one time I could run and not overheat. And now I mostly am at idle. Any car as old these will have problems if not maintained properly. They just need to reconditioned back to how they were when they left the factory. Then you could drive them cross country in the middle of summer if you wanted to. MY dad said they towed a trailer across the desert in summer every year from North Dakota to CA with a Mercury and it never overheated.

[jimTN]

Your problem could well be the radiator. Old radiators exposed to road salt and dust over the years end up with the fins not making good heat transfer contact with the tubes. They may look good but not work well at all. I also second the suggestion about Skips water pumps.

[Flathead Fever]

I thought of another story. I had an F-800 at work that was over-heating, so I removed the radiator. It takes an overhead chain hoist to do it by yourself, giant radiator. I had two different radiator shops I used. I sent it out and had it re-cored. Put it back in and it still over heated. I replaced everything, water pump, thermostat, checked the timing, checked the vacuum advance and it would still overheat climbing over Little Mountain. I had to take another radiator to a radiator shop so to spread the phone company wealth I took it over to the otter guy, an old-timer, bag pipe player, in a galvanized metal-sided 12'X12' building that had been there since the Model T era. So, I asked him about my F-800. He said, "did they use the small tube core of the large tube core"? Guess which one they used. That solved the problem. The other overheating problem that kicked my butt was I replaced a leaking water pump on a 318 powered Dodge van. The radiator looked cruddy inside so I went ahead and replaced it, the thermostat and all the hoses too. That ways it's not coming back for years right, wrong. It started overheating the next day. It wasn't over heating before "I" touched it. I tried another thermostat and it still over heated I checked everything. I pulled the new quality brand "new" water pump off and the impeller was spinning on the shaft. I will never install another water pump without checking that impeller fit.

The point is we don't know what has been done to these radiators. You don't know if its been re-cored with the right size and right number of tubes. Maybe its a cheap replacement. The aftermarket industry made everything for these cars but the block from the 1930-1950s Even if its rodded out or re-cored does not mean its not the problem.

Another one I had that camelback from radiator shop #1. I have no idea how he did this unless he was blind. He used so much solder on the top tubes he soldered them shut. How could you not see that???!!! I fired him after that and stuck with the old-timer. I had him re-core my original '32 radiator on my roadster project. I sure wish he was still alive. That's' another "unfinished" project I have.

[mfirth]

I've only had 8ba flatheads & only had minor, easily cured heating issues. I have a friend with a 38 Ford who runs NO FAN & has no heating issues. Interesting .....

[Terry,OH]

When you remove the oil pan also remove the welsh plugs in the block pan rail. This will let you into the block coolant passages. Use a coat hanger and scrape and brake up the casting sand, especially at the rear of the block. Get as much out as possible. Can even run water into the block from the water pumps to flush out more sand. Then install new plugs, using a sealant around the inside and edges of the plugs. This can be done with the engine in the car.