1932 Chevy overheating problem

My Fire Company has a 1932 Chevy truck that has always run hot on really warm days, but in the past few years it has started to overheat on shorter rides, and in cooler temperatures. For years it never had a thermostat, so I put in the correct thermostat. I’ve also replaced the water pump, and we had the radiator recored. It threw a rod a few years ago and we had some engine work done to replace the rod and a piston. We only take the truck to parades and it’s been run since it was purchased in 1932. It does sit all winter in a garage, but usually starts right up in the spring. Any ideas on what might not be right? How can I cool this truck down?

Maybe retarded timing? Can it be fitted with an electric fan?

Did you put a 50/50 mix of anti-freeze in it? Make sure that you have a low-temperature T-stat in it, like down around 180 deg. Many newer T-stats are set at 190, 200, on up to 220. If that isn’t the problem, then just pull the T-stat right out. See if it runs at the same temp. as before. “While you’re there”, do another check of all hoses. You may have a partial obstruction from some crap coming out of the engine water ports. One other fix you can try if all of this checks out O.K. is to get a fan with more blades. If you’re ‘parading’ it, the truck is not getting full benefit of ambient air pulling heat out of the radiator at low speeds. A fan with additional blades, say a 5-blade instead of a 3 or 4 blade fan will pull more air through the radiator at the same R.P.M.s.

Is there any discolored coolant, like from rust? Probably not as your moniker (or handle) seems to imply that you have used/abused knuckles. You or your Fire Company probably flushed the cooling system thoroughly. An old piece of gasket or a piece of old rotted hose might have gotten hung up in the system somewhere and is now rearing its ugly head. I’d say just thoroughly recheck the cooling system and, if necessary after you have excluded other things, get a fan with more blades. An option would be to ‘jerry-rig’ an electric fan, but it’s a '32, so you might have a huge challenge finding a 6-volt electric fan. Then is the challenge of where do you put the fan control switch? For these kinds of changes, you might want to check www.jcwhitney.com Let me guess. 6-volt Delco w/ a generator, maybe even positive ground? And I’ll bet that the generator probably has a contact points relay right on the generator? My opinion: easier to track down a 5 or 6-blade fan.

Yeah. That’d be another good check. The timing, but check the distributor for any ‘slop’. Very little slop is O.K. A lot of slop will affect the timing. Did anyone recently check the spark plugs for proper heat range? Running too hot a plug will affect coolant temps.

I do have a 50/50 mix, and for quite a few years we did run without a T-stat. I added one recently thinking it might help in the overheating problem by slowing down the flow through the radiator. The fan does have 5 blades and there really isn’t room for an electric fan, and it is 6 volt, so that would be a problem. The fluid looks good now. When we had the work done on the engine it was all flushed out. The hoses are all new. I’ll have another guy check the timing and the plugs. It never hurts to have a new set of eyes check things out. We even had the vacuum advance fixed.

It doesn’t give us a problem in the parades usually, it’s getting there and back. It always had a tough time on the biggest hills, but now it overheats on smaller rolling hills, and on some of the flatter areas too.

Oh, the Knuckles moniker is deceiving. When I first joined the Fire Co my brother and I were being a pest at a meeting. He dropped his knife and almost got one of the older guys stabbed in the foot, so they called him Killer, and I almost ended up with a knuckle sandwich. I’m far from looking like a Knuckles, but it stuck.

The only other thing that I can think of is the water pump. Could be that the pump impellers are just slowly disintegrating. I think that we’re now down to a too-low volume of coolant. Water pump. Those trucks of the time were designed/modified to idle at higher RPMs to be able to operate the PTO and other accessories. On ‘the flats’, not a big problem, right? It’s only going up hills. I can’t think of anything else other than the water pump. Any other suggestions, Folks?

The water pump I bought was a NOS off ebay. The old one I took off looked just about like the new one, and the impellers looked just like pictures from a rebuild kit. They look like they should be in tip top shape. I was let down when I took off the old pump and it looked in good shape. I really was hoping they were worn off and not pushing enough water. Thanks for your ideas.

How is the oil pressure on the engine? I ask this question because you have done about everything possible to the cooling system. However, it seems to me that I remember somewhere that low oil pressure may cause engines to run hot.

My guess is that your engine is an overhead valve, but is splash lubricated with babbitt bearings. If this is the case, there is an oil pump that supplies oil to the camshaft bearings and the rocker arms. When the engine overheats, does the oil pressure drop off? If so, the problem could be either in the oil pump or in worn camshaft bearings that lose pressure when the engine warms up. Were the camshaft bearings serviced when the engine work was done?

My Dad had a 1939 Chevrolet and I don’t think that it had a pressurized cooling system. I think he ran a 160 degree thermostat in the summer and a 180 degree thermostat in the winter. I do remember having an overheating problem which was finally solved by having the radiator core “rodded out”. However, you have recored your radiator so I assume that the radiator is o.k. The only other cooling system problem that I can think might be a culprit is that for some reason the fan is running backward and not pulling air through the radiator. I don’t understand how this would happen, but I’ve heard of it. It’s an easy check to see which way the air is flowing.

Interesting problem, have you considered changing the pulley size to increase the waterpump/fan speed and increase the cooling?

I had another thought: Could the exhaust system be restricted? A check with a vacuum gauge would be a way to check for this condition.

I’ll have to watch the oil pressure closer. I’ve never noticed it going down.

I’m not sure how easy it will be to change the pulley. The pulley on the crank shaft is welded on. Only reason I know this is about 15 years ago coming back from a parade it came off and we just welded it back on. It’s amazing what you find on a truck this old after it’s been through so many drivers over the years.

I think my brother and I changed the exhaust about 20 years ago. It just shoots out from under the floor boards and has always seemed to have plenty of flow. I’ll check that also.

If you would like to see a picture of the truck, it’s on our web site. http://waymartfire.com/APPARATUS%20HISTORY%20-%20WVFC.htm

As Lt. Colombo would say: “Just one more thing”. It may not be important, but what weight oil are you using in this engine? I don’t know what the specifications are for a 1932 Chevrolet truck engine, but I’m certain it doesn’t use a multiviscosity oil. My guess is that with the clearances in this engine, it would require a straight 30 weight. I do remember getting an air cooled lawnmower engine awfully hot when I put in 10 weight by mistake instead of 30 weight. I doubt that this is your problem, but you’ve seemed to rule out anything in the cooling system.

Thanks for sharing the pictures. Maybe the 1932 Chevy is just p.o’d at having been forced into retirement. I have some colleagues trying to do the same thing to me and this makes me pretty steamed up and overheated.

Seriously, the cooling system had to be ample at one time for the truck engine to pull the pump when putting out a fire. In stock form, it should be fine for parade runs when everything is o.k.

I’m still thinking about your fire truck. I wonder if the passages in the block may be plugged. Is there a petcock on the block and when you open it, does the coolant flow freely? It seems to me that there may be distribution tubes for the coolant that go through the block. If the coolant passageways in tte block are plugged, this could cause overheating. I’m certain that there is a way to remedy the problem, but someone more knowledgeable than I am will have tell you how this is done.

I only use 30 weight non-detergent oil. Usually I use Valvoline.

Is your temperature gauge accurate or is the cooling system actually boiling over? Cooling systems in early 1930s Chevolets may have been marginal as I recall. A long time ago a friend and I were searching for old car parts on farms in the late 1950s. One guy had a practically brand new radiator for a 1931 Chevrolet car. It had an upper tank as thick as the radiator. The guy who had it said that they had replaced their radiator with one with an extended (larger) upper tank to fix the overheating. I don’t know how this would help but that’s what he said.

To help zero in on the problem, see if you can find someone with a noncontact infrared temperature tool. With the engine running at pumping speed ( ~ 2500 RPM) and the temperature near overheating, measure the top tank, bottom tank, a piece of sheet metal subject to the outflow air coming from the radiator, the ambient incoming air, block wall front and back, head front and back, and thermostat housing temperatures. Also, run your hand across the front of the radiator to see if it is uniformly warm. Also is there any gas bubble getting into the coolant. With this information, we should be able to diagnose where the problem might lie.

Hope to help.

I’ll get our thermal imaging camera out and try that to see what the temps look like, and try to find a temp tool. Thanks.