VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 Over heating issue on 36 fire truck 206 CI 6 cyl

I have an over heating issue that I am sure is happening due to water loss. When my truck is idling it will not over heat. When you accelerate the fluid starts to come out the over flow. I have a thought that the top tank on the radiator is wrong. When you look in the radiator cap the discharge flows directly in to the top. When I look at the repair manual for a 36 Chevy it says that there should be a v shaped baffle that directs the water down. I know that the tank was replaced by the previous owner. Any thoughts on the way the top tank should be, or any comments would be appreciated in solving my over heating problem

The two most common problems are filling the radiator too full, (should be just above the top of the core) and sucking air in past the impeller shaft (displacing coolant).

Would you like for me to take a look into the tank on my '36 1.5 ton to see what's there?

Mike

Mike,
Thanks for the offer. It would be good to see if there is a baffle or not. Do you have any heating issues?

Tim

My truck is a work in progress. I have driven it some, on the farm, but not enough to know how things work.
I seem to recall that I was not getting much of a reading on the temp gauge. I concluded that the gauge was bad. I have a supply of used and NOS ones to choose from but figured I would do that when I rewire.
I was starting it one day after removing the rusted exhaust pipe and could hear a distinct puffing sound, so I assume I have valve problems of some kind. The head is coming off soon.
I'm going for that "as found" look but trying to get everything working as it should so it will be reliable enough for some chores and short trips.
So far, most of the parts I have needed have come from my own stock of stuff, I've only had to buy rear brake linings, some rubber stuff, brake cylinder kits and hoses.
In my stash, I found:

Front brake linings
King pins
Front spring shackles and bolts
Parking brake cables and rubber dust covers
Foot Accelerator rod
Correct fuel pump and kit
Headlamp lenses
Taillamp and bracket
Windshield frame
Passenger side door handle (now keyed to match ignition)
Front license bracket
Wiring harness
Radiator cap
Crank hole cover
Glove box liner
Master Cylinder
Front and rear wheel seals
Water pump
Horn button
Mast jacket bushing and horn wire
And probably more

The truck came with a working PTO and hydraulic hoist but no platform on the bed, only the stringers.
It's been a lot of fun to work on it and there is lots more fun to be had.
I'll get a look into the radiator and report back on the baffle situation.

Mike

My truck has a baffle in the upper tank.

Mike

How long can it idle without overheating? It would be very odd to not overheat when idling, but to overheat when engine speed is increased. Could your thermostat be stuck,cold when the engine warms up at idle and then boiling over at the increased speed when the water gets hotter? I have found that my 206 will immediately have overheating problems if it is out of time.
Richard

I would suspect that the rust coming from the block is plugging up the radiator core.

I took my radiator to a radiator shop and had it flow tested. It was not restricted at all. Good flow through the radiator. I really think the issue is it is the wrong top tank on the radiator. It will idle all day long and not over heat. As I said in my original post when you look down in the top of the radiator you can see the top radiator hose inlet. The radiator does not have the V shaped baffle to push water down through the cores. When you accelerate it shoots directly into the filler neck and out the overflow. When accelerating you can see a steady stream of water coming out the over flow. So with that said while I had my radiator out I Made a change to see if I could correct this. I soldered the top in let closed and installed a new filler in the side of the top tank inside of the motor compartment. I put a 5 lb pressure cap on and filled her with water. I took her for a test drive and climbed a big hill on the edge of town to see if it would over heat. No problem ran 180 degrees like clock work. No more over heating. For now this cures the problem. The issue is I want to put the right tank back on. For now its handled, all I have to do is find the right top tank now. Thanks for all your input. Tim Kelley Castroville Texas

I think I have some extra radiators. Maybe one is junk and could give up it's top tank for your truck. It will be a couple of days before I can look. Email me direct at ml.russell@mchsi.com and remind me to take a look. According to my parts catalog, all '34-'36 big trucks shared the same radiator.

Mike
Columbia, MO
573-442-6759