Technical Overheating head scratcher

My take, from MANY years of experience, is the radiator is not flowing enough water for the engine. Could be too small. Could be plugged. Could be something else.
Change the fan to a puller, if space allows. Better, change to manual, if space allows. Get the engine hot. Spray the front of the radiator with water and observe the drying pattern. Might be revealing.

Ben

 

! Question did you Change the Radiater Cap.??
Just asking I had a little Problem like that did everything like You
did & everything Helped
Changed the Cap & now its History

Just my 3.5 cents

Live Learn & Die a Fool

 

is it running lean when its getting too hot? have you checked the plugs?

 

Can I ask a few really stupid questions?
A '40 Dodge coupe I'm assuming (I didn't take time looking it up) would have had a much smaller motor, a flathead 6 I'm guessing. So as it was designed (grille, therefore airflow) wouldn't need to be that much.
I'm thinking if you take any factory vehicle the cooling system will be adequate at idle and highway. Block grill with cardboard in summer it overheats (winter may be beneficial).
So my question: Is there anything in front of radiator like ac condenser or trans cooler? And I'd like a picture of front grill area.

Sent from my SM-S320VL using Tapatalk

 

Friend had a similar situation. Blown 392 in a old coupe did all the things you have done then added 2 more smaller radiators in behind the front wheels, protected them properly, those added almost 2 more gallons of coolant to the system
It cured the problem.
GM has I think 5 radiators in the new ZL1 Corvettes to stop their over heating problems of last years model.
More coolant I say! Good luck, I hate heating problems.
I don't know if this question was asked before. What compression ratio?

 

Sounds like a problem I had on a '57 T-Bird years ago. I started by replacing the radiator since it was old and needed replacing anyway. Didn't solve the problem. Checked the timing, right on. One day I was driving about 30 MPH on a surface street and noticed a surging in the power. Traced it to a busted diaphragm in the distributer. Replaced the diaphragm and solved the problem. The timing had checked out since it was checked with the vacuum advance hose removed. With modern test equipment you should be able to check the timing at higher RPMs with the vacuum line connected. It had been ok at low speeds but at high speed the timing was far enough to cause the overheating. Have you noticed any surging lately? Be sure to post the final solution to the problem.

Charlie Stephens

 

when engine was rebuilt how far was it bored out and was the block burned and cleaned thoroughly, had a problem years ago with a chevy engine found out the water jackets were plugged with casting sand from the factory. once that was corrected engine ran cool when driving or sitting. just a thought! humbly john!

 

Along the lines of what a few others have said, I'd make a map of the surface temperature all over the radiator when "overheating" is imminent. If there a some cool spots on the radiator I'd say those sections are plugged with something and not flowing well, and not providing much cooling. The temps near the inlet should should be HOT as the engine, and the temps near the outlet should be noticeably cooler. I'm guessing 20 - 40 ° F cooler. If the exiting water temperature is not significantly cooled, I'd guess the airflow and or waterflow through the rad is insufficient.

What sizes are the crank and water pump pulleys ?

Is the paint still visible at the bottom of the pulley v-grooves? If the belt(s) are too narrow, they ride the bottom of the pulley grooves instead of the tapered sides and can't transmit much power at all without slipping.
I did not catch if you have fan clutch or not. I'd say grabbing and turning a regular steel fan (bolted to the water pump) by hand should not slip the water pump before turning the crank pulley.

 

I'd guess flow restriction of some kind. Plugged or partial plugged core or just not enough core.
Years ago I took a 65 ford, 302, 2drht in trade. Had a burned valve, but I had a pair of heads with a fresh valve job in storage. Took them out, and since I had painted them and intake when the valves were ground swapped heads and intake. Ran great. Except it had the exact symptoms you are experiencing. After a lot of tail chasing, I took the thermostat housing off and for some reason, while it was off I put a water hose in the radiator. Lo and behold out of the intake came floating a couple of pecans. Damned rats! Apparently stashed while I had the intake on the shelf in the shed.

 

I just went through this not long ago with a buddy's 47 Ford - He had one of those silly chromed copper serrated upper radiator hoses that look marvelous and work like crap, changing that solved most of it, then I realized that at speed, the lower hose was collapsing on itself when the thermostat opened... new hose & a spring and problem solved.

 

A local guy here in town had problems overheating(302 in a 55 Ford) until he installed a tranny cooler. He fought the problem for over a year.

 

indcontrols...yes yes yes...forgot about that. Collapsing lower hose due to no internal spring. I don't think anybody had mentioned that possibility yet. Fits the symptoms perfectly.

 

Pusher fan has to go. Blocks too much air at highway speeds. I've got a puller and can actually shut it off at highway speeds. This is with a full race flathead and you know what they say about flatheads. Nothing overheats quicker than a flathead.

 

Pusher on the engine side or grill side?

 

Grab a temp gun check inlet and outlet temps and check for cold spots in the radiator.

 

pusher = grille side
puller = engine side

 

Sounds like a simple case of the pusher fan restricting the air into the radiator. If it cools fine in town, you have an air restriction problem at speed.
SPark

 

I went through this with a 63 Nova wagon. The thread may even still be in the archives on here. I changed the electric fan and the problem went away. It was a swap meet electric fan. It was basically just in the way on the highway.

 

Yep...tried that too!

 

Would have done mechanical, but the radiator sits too high compared to the motor. I basically went with a pusher just because it is hidden behind the grill...but sounds like that is the first thing to try.

 

Originally didn't have a spring in there...but fixed that too. To no avail.

 

It's just the stock pulleys that were on the motor. Never thought about the belt slipping...that's a good thing to check. One of the few things I haven't checked.

It's a new radiator...so hopefully nothing plugged. I haven't checked the outlet temp because I don't have a heat gun handy...but that would also be good info.

 

Checked. They are a nice light brown, so seem fine. Running an edelbrock 650.

 

I do have a small trans cooler near the top of the radiator. I thought that would be less detrimental than using the cooler in the radiator. No A/C. Yes this definitely a much bigger motor than it had originally. I've built air dams so all the air has to go through the radiator and can't sneak around it.

 

Thought I had a better picture of the radiator, but this gives you a basic idea of the set up. You can see the radiator is quite a bit higher than the motor, so the lower hose setup is not ideal...but basically used a 90 bent tube with short hoses to connect. Looking at this picture...yes that fan does appear to be a nice restriction.

 

I really like the car!

Ben

 

Just a stupid question is the fan pushing air or pulling air.

 

Pushing.

 

Front mounted fans push.
But they suck.