VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 Overheating and a pusher fan

My 36 1/2 ton has the occasional episode of overheating when It is a hot day and traffic is not moving. Before anyone asks: Radiator is clean, block is clean, water pump is new and not sucking air, thermostat is new and working and timing is right on. An IR thermometer shows no hot and cold spots on radiator. Again, only an occasional problem. I am considering putting a pusher electric fan in front of the radiator so it is not very noticeable. I have spoken with another VCCA member ( Wino Wally ) who has done this and is quite happy.Has anyone else done this that would share the pros and cons with me? Also, what size fan should I select and should I get the kit that operates the fan based on water temperature? My main concern is that they seem to pull 8-9 amps when running. I imagine that would be ok, since I wouldn't be running the heater or headlights when It is that warm a day. Please, any thoughts?
Richard

Another cooling solution is to plumb a modern transmission cooler (a small radiator unto itself) into the oil line, thus cooling the oil, which in turn helps keep the engine a little cooler.

I did this on my 1927 truck and it seems to help.

Cheers, Dean

Grasping at straws here, but you could have some blockage between the head and block...Last time you had the head off...? I've thought of adding a fan myself, as I have the same problem...Another question is are you still running 6 volt and can get a fan that's 6 volt, too...?

Kevin, good point about blockage between the block and head.

When I took the head off my '28, I found the previous owner had put extra sealant around the water holes of the head gasket. The result when he tightened down the head was that the extra sealant 'squished' into the orifice and blocked over 1/2 of the flow area!

Glad I found this before I ran the engine too much.

Dean

Head was off not long ago, no blockage. Yes, It is 6 volts and getting a 6 volt fan is no problem.
Richard

Richard,

An option is a fan shroud. I have the bottom 1/2 of an original '34-'36 PU & truck fan shroud but not the top. Decades of looking has not turned one up. One guy contacted me with one he had for sale but his price was what I paid for the complete, rough but original, running '36 pickup so I found his offer laughable. If someone has the top 1/2 sitting around gathering dust it could be used as a mold to make a fiberglass copy. In fact, from the pictures I have seen it would be easy to copy using sheet metal because it is a very simple part. The same could be done with the bottom 1/2 I have.

Is anyone up for this project?

I too have been looking, for years, for either half of the shroud with out much luck. Several years ago I spotted a radiator with the attached top shroud on Ebay, but It was gone before I could buy It. I believe they were an option for the 1 1/2 ton trucks.
Richard

Richard
The pusher fan idea works well on later models so I see no reason why it wont work in your situation. I would go with the temp control but dont take the power directly off the battery, use a switch preferably the ignition switch that way the fan wont drain the battery if you forget to turn it off (it does happen).
Tony

Tony, good call on the switch.
Thanks, Richard

I think that we all have cooling problems with our old cars on very hot days. I too am in that category.

I have fitted a 6 volt fan from the filling station, to the outside of the radiator. I wired it in with a separate switch not hooked to the ignition.

I have the generator conversion (Peterson) and when running the fan, the ammeter shows a discharge , whilst it is working. When the car stops there is no way that I could forget to turn it off.
It makes a lot of noise...........

It certainly helps keep the water temperature down on a hot day and would recommend it to anyone that is experiencing overheating problems only on hot days.
Thats my my penny's worth...

Peter

Peter, thank you for your input. I am surprised that your amp meter shows a discharge, since they pull about 9-10 amps and I would think that a stock generator should keep up with It. However, I am not familiar with a Peterson conversion.
Richard

Richard,

The 3-brush generator does some really unhelpful stuff like charging less as RPM increases and overcharging the battery, shortening its life. The Peterson regulator cures those ills.

There is a 1933 Plymouth forum and an article on it inspired me to try a Peterson regulator. It came to me on a non-working generator that I picked us as a spare. My son, an electrical engineer, found a toasted part in the Peterson regulator and fixed it. The Peterson regulator had been installed by an auto electric "Professional" who connected only 2 of its 3 leads, causing the failure.

Now there is no drop off in generator output with increasing RPM, the charge rate is high when the battery has just started the engine and tapers off to a trickle when the battery is recharged and the generator output is even enough for 25W/25W halogen headlight bulbs. It's great being able to see the road in the dark!

I ran a pusher fan on my 37 due to having a 235 and not knowing about the water pump adapters,it worked great but my truck is 12 volts and a alternator.

brino,
I have run a Peterson regulator for about 10 years. It is the first installed in a Chevy and still working well. Despite Jim's recommendation to used diode it still uses and original cut-out. I move it from vehicle to vehicle depending on what I am taking on the next VCCA tour. I would estimate that it has over 10k miles. A VCCA member has told me that I would have a prototype improved design by the first of the year. Watching the mail but not yet.

Hi Chipper.

Happy New Year!

I was very happy to discover the Peterson regulator because it makes the stock '36 generator capable of doing what it is supposed to do, and even the added task or powering halogen headlights. I had contemplated a more ambitious solution, putting a motorcycle alternator inside a '36 Chevy generator case but now that won't be necessary.

That's great that you put so many miles on your antiques. I wish I could meet some local antique car guys who enjoy doing that. Most don't trust the reliability of their antiques enough to venture far from home. My attitude on that is that these antiques were once new and were trusted transportation. If they were trustworthy "then" they should be trustworthy now if properly restored and maintained.

There are at least 7 VCCA tours each year that limit participation to pre'55 Chevrolets. A couple limit to '28 and earlier. I would guess that the total mileage for those tours is over 2000 miles. So even if you can't find local folks there are some across the country that enjoy driving these old Chevys. Yes there are a few breakdowns and repairs but the majority are handled on the road or a parking lot and the vehicles back on the road in short time. And the repairs only require basic tools.

Richard,

It is obvious by testimonials from others that the pusher fan will help in cooling.

My questions are:

a. Just how hot does it get? 180? 185? 190, etc? Does it boil over?

b. Have you flushed out the block and back-flushed the radiator recently?

c. Have you checked for combustion getting into the warted jackets?

On a hot day sitting in traffic, you can expect the coolant temperature to rise some. To about 190 or so. If you are close to sea level it should not boil over (212 degrees).

The notion I have is that if every thing is in good shape - block, radiator, thermostat, head gasket, no cracks, and good hoses. Then there shouldn't be any concern. If you have to run the heater to help keep the temperature down or install a pusher fan, then you are just treating the symptom and not the problem. Something else is going on.

Remember: As long as there is coolant in the block and head you are not going to really harm anything. It is when the loss of coolant gets below the pump and/or is not circulating that the damage is done. So if it is not heating up enough to lose coolant don't sweat it. It will be just fine.

Without more (than you have described), I wouldn't mess with no stinking pusher fan. And, I would be real careful about cooling the engine erl.

Some folks believe that the cooler their engines the better. Not so. About 180-190 is about right.

Best,
Charlie



c

I'd consider having an over flow tank as well...Extra water...Maybe I'm just grasping straws, as usual...

Wonder if Charlie's is on to something here...Could there be a combustion leak at the head gasket...? I've re-torqued the head bolts and had some success...Hard to tell if the system is not pressurized or you have no over flow tank...I never use sealer on head gaskets...Leak down test might reveil something...Since every thing else appears normal...Might check the thromsat again...Try it in boiling water...Your not running an old style are you..?

Charlie,I hear you, but...
Not often, but on hot days with prolonged idle it will hit 212 degrees and boil over. The engine has had a complete overhaul of the engine and head. The water pump, hoses and thermostat were replaced as well as a trip to the radiator shop.I re-torqued the heads and did a compression and a leak down test at that time.

I do believe that these engines (206.8) were not efficient enough to handle a hot 90+ day at an idle for very long evidenced by most owners I have discussed this with. Who knows, maybe an electric pusher fan Is this answer that Detroit forgot.

Most of the fan thermocouplers kick on at 185 and off at 170.

I think I have done everything I can to find a problem that causes this, but It may be inherent to the beast and only solved by a nice cool, not cold, fan.

Appreciate all the thoughts and comments.

Richard

Non pressured system, thus no overflow tank, but extra water is always carried. I did heat the thermostat on the stove and measured the opening temp. All ok. Thermostat is new. What is old style verses new?
Richard

Old has "bellows"...New looks like a modern type...Think it was Gene that said, not to use the old style...Use it as a xmas ornament...

Got ya, thanks. Using new style.
Richard

What fan do you have on it,I know the 37 and newer larger trucks had a optional 6 blade fan but heard they made a bit more noise then the normal 4 blade fan. I did find the top part of the shroud for my 37 and not really sure if it helps any since I had a 4 row radiator built for the 37 and it never got hot before installing it but put it on because I was abe to find one.

In the last couple of years there was a large discussion about 1933-1936 cars overheating.

I proposed that if everything is right and nothing leaking internally , head gasket, then I pointed the evil finger at the stock 4 blade fan , not being able to draw enough air over the fins and tubes to cool the water/antifreeze mix.

Phil Lipton ( VCCA ) of OHIO purchased a steel 6 blade fan from Vintage Air and did a bunch of tests for air flow and was very happy with the results. Unfortunately Phil was unable to easily adapt the 6 blade fan to work on the stock setup. Phil is an accomplished machinist .

See if I can get Phil to chime in with his results and tests.


mike lynch

Yes, It has the stock 4 bladed fan. If a six blade gave good results then It would confirm that an electric fan could also do the trick as others have stated.

I remember in the 60's replacing stock fans with a fan that would flatten and flex to move more air. Can't remember if they did much good or who made them.
Richard