The Ford Barn

The 35 Jezebel · 06-11-2022, 09:13 PM

On my ‘35 flathead I’m having problems with overheating. I can drive it one weekend 20-30 miles and it will never overheat then the next weekend it will run hot to whole time. I had the radiator checked, flushed the engine and use distilled water with water wetter. Why is it not overheating all the time and why does it overheat out of the blue. I need help!

alanwoodieman · 06-11-2022, 09:21 PM

loosing water? white smoke out of tailpipe? overflowing the radiator? pressure system? take cap off run engine until warm, make sure the water level is above the fins and below the cap, put the cap on and then take it for a run and see what happens

19Fordy · 06-11-2022, 09:22 PM

Hoses collapsing, bad thermostat?

The 35 Jezebel · 06-11-2022, 09:31 PM

Blows the water out of the overflow tank, no pressure cap and I keep the water just above the fins. The hoses are new and no thermostats.

19Fordy · 06-12-2022, 10:48 AM

When you look into the radiator can you see the water flowing when you first start the engine when the engine is cold and also see the water flowing when the engine is warmed up to operating temperature?

Bored&Stroked · 06-12-2022, 11:15 AM

Sponsored Links (Register now to hide all advertisements)

Are you using thermostats? Sometimes a thermostat might not open, or only open part way - causing overheating issues like you're talking about.

Jacques1960 · 06-12-2022, 11:31 AM

Also check coil

38 coupe · 06-12-2022, 12:50 PM

How you drive it may be a big factor. Many early Ford V8s do not like idling for long periods of time, particularly after a good run at speed. Does your car cools acceptably at 20 to 45 mph, but not when you drive faster or slower?
What temperature does it run when it is not overheating?
How hot is the ambient temperature for each drive?

Lanny · 06-12-2022, 04:09 PM

Are you running a mechanical fan, or electric ?

.

Lawrie · 06-12-2022, 05:07 PM

Bite the bullet and remove the radiator and take the top tank off , then you can make sure you have no blocked tubes.
Lawrie

38 coupe · 06-12-2022, 05:27 PM

I agree with Lawrie's advice. A San Antonio friend with a 36 recently fixed the overheating problem on his car. He had the radiator cleaned, cleaned the block with dilute phosphoric acid then with baking soda solution, and installed Skip's high flow water pumps. Each step helped, but didn't solve the problem. Finally he took the radiator to a different shop, had the tanks pulled and the core rodded out, and that solved the problem. I test drove the car on a 98 F day with no overheating on an extended run last month.

JM 35 Sedan · 06-12-2022, 11:22 PM

Check to see if you might have combustion leaking into the cooling system. I had this happen on my '35 in 2019 on my way to Auburn Indiana. Turned out to be a blown head gasket.

06-11-2022, 09:13 PM	#1
The 35 Jezebel Junior Member Join Date: Apr 2022 Location: South Boston, Va Posts: 2	Overheating Flathead On my ‘35 flathead I’m having problems with overheating. I can drive it one weekend 20-30 miles and it will never overheat then the next weekend it will run hot to whole time. I had the radiator checked, flushed the engine and use distilled water with water wetter. Why is it not overheating all the time and why does it overheat out of the blue. I need help!

06-11-2022, 09:21 PM	#2
alanwoodieman Senior Member Join Date: May 2010 Location: upstate SC Posts: 3,000	Re: Overheating Flathead loosing water? white smoke out of tailpipe? overflowing the radiator? pressure system? take cap off run engine until warm, make sure the water level is above the fins and below the cap, put the cap on and then take it for a run and see what happens

06-11-2022, 09:22 PM	#3
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 11,605	Re: Overheating Flathead Hoses collapsing, bad thermostat?

06-11-2022, 09:31 PM	#4
The 35 Jezebel Junior Member Join Date: Apr 2022 Location: South Boston, Va Posts: 2	Re: Overheating Flathead Blows the water out of the overflow tank, no pressure cap and I keep the water just above the fins. The hoses are new and no thermostats.

06-12-2022, 10:48 AM	#5
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 11,605	Re: Overheating Flathead When you look into the radiator can you see the water flowing when you first start the engine when the engine is cold and also see the water flowing when the engine is warmed up to operating temperature?

06-12-2022, 11:15 AM	#6
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,723	Re: Overheating Flathead Sponsored Links (Register now to hide all advertisements) Are you using thermostats? Sometimes a thermostat might not open, or only open part way - causing overheating issues like you're talking about.

06-12-2022, 11:31 AM	#7
Jacques1960 Senior Member Join Date: Sep 2020 Location: Mount Desert, Maine Posts: 504	Re: Overheating Flathead Also check coil __________________ No job’s done ‘til it’s all done

06-12-2022, 12:50 PM	#8
38 coupe Senior Member Join Date: May 2010 Location: South Texas Posts: 2,042	Re: Overheating Flathead How you drive it may be a big factor. Many early Ford V8s do not like idling for long periods of time, particularly after a good run at speed. Does your car cools acceptably at 20 to 45 mph, but not when you drive faster or slower? What temperature does it run when it is not overheating? How hot is the ambient temperature for each drive?

06-12-2022, 04:09 PM	#9
Lanny Senior Member Join Date: May 2010 Location: Mn Posts: 2,543	Re: Overheating Flathead Are you running a mechanical fan, or electric ? . __________________ If mama ain't happy, ain't nobody happy. But if daddy ain't happy...RUN What I GOT DONE TODAY... I got the rear-end put in the recliner, and now I'm going to rest up & watch TV.

06-12-2022, 05:07 PM	#10
Lawrie Senior Member Join Date: May 2010 Location: Qld, Australia Posts: 4,529	Re: Overheating Flathead Bite the bullet and remove the radiator and take the top tank off , then you can make sure you have no blocked tubes. Lawrie

06-12-2022, 05:27 PM	#11
38 coupe Senior Member Join Date: May 2010 Location: South Texas Posts: 2,042	Re: Overheating Flathead I agree with Lawrie's advice. A San Antonio friend with a 36 recently fixed the overheating problem on his car. He had the radiator cleaned, cleaned the block with dilute phosphoric acid then with baking soda solution, and installed Skip's high flow water pumps. Each step helped, but didn't solve the problem. Finally he took the radiator to a different shop, had the tanks pulled and the core rodded out, and that solved the problem. I test drove the car on a 98 F day with no overheating on an extended run last month.

06-12-2022, 11:22 PM	#12
JM 35 Sedan Senior Member Join Date: May 2010 Location: Near Rising Sun, Maryland Posts: 10,876	Re: Overheating Flathead Check to see if you might have combustion leaking into the cooling system. I had this happen on my '35 in 2019 on my way to Auburn Indiana. Turned out to be a blown head gasket. __________________ *John* *"Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein*