1923 Chevy overheating.

[AllenWConrad]

I just bought a 1923 Chevy.  It starts easy and idles good.  But when I drive it,  it gets hot and over heats fast in less than 100 yards.  I know the water pump is working.  Can someone point me in the right direction.

 

Edited June 3, 2021 by AllenWConrad (see edit history)

[dictator27]

Plugged radiator?  Crud in the water jacket?  Anything that overheats that quickly has serious circulation issues.  How do you know the water pump is working properly?

[AllenWConrad]

The radiator water runs freely threw it.  I flushed it removed hoses etc etc etc.  The water pump is running because i removed the outlet hose and put a longer one on it to remove water away from car.  Started the car and water came out.  

Edited June 3, 2021 by AllenWConrad (see edit history)

[AL1630]

The first thing I would check is to see if the block is all plugged with crud. Take the hoses off the radiator, and aim a garden hose into the block. If a bunch of brown water and dirt comes out then that's probably a part of the issue. The amount of scale and rust chunks that came out of my engine the first time I did that was unbelievable.

[AllenWConrad]

al1630 I did that also.  The water was clear, and ran pretty freely. 

[Ken_P]

If you’ve checked the radiator flow, checked the block clean, take a look at your plugs. Maybe it’s running very lean?

 

If those check out, do wet and dry compression checks and a leak down check, to make sure your head gasket is sealing.

 

I would also dig into the water jacket as much as you can.

Edited June 3, 2021 by Ken_P (see edit history)

[AllenWConrad]

Ken P Im pretty sure the block isnt clogged. I ran water through it and it came out the bottom,

[Ken_P]

PS - welcome aboard!

[nickelroadster]

make sure that your timing is not retarded.  Even though you say you have clear water coming out of the engine you may still have some passages plugged up.

[AL1630]

Yeah, check all the tune-up stuff. Carb, plugs, distributor, etc. My car used to overheat quickly at any temperature above ~80 degrees, especially running at higher RPM. I tried all sorts of stuff - New water pump, checked timing, flushed everything several times, checked for air bubbles etc. Eventually someone suggested that the distributor bushings might be worn out, causing 'self-setting' timing since the shaft would move around as it spun. I replaced the distributor and what do you know, now it runs at thermostat temperature even in the high 90s.

 

Also check the oil - any signs of water in it?

 

That said, in my situation it took 10-15 minutes of driving before it got too hot. If your car is only going 100 yards before heating up, that makes me think it's a flow issue or even a bad gauge, or something else (like timing) is way off. Most cars don't even get up to operating temperature that fast.

 

Also, I second the welcome!

Edited June 3, 2021 by AL1630 (see edit history)

[Flivverking]

Water runs freely means nothing...It could have 1/3 or more of the tubes blocked completely but water runs through open tubes fine .A radiator in such condition has a low capacity and can not cool at all.  
If the radiator holds a gallon and a half of water when unplugged clean..with solid plugged sections of tubes you may only have a gallon pushing through or worse.

 

 Will it over heat just idling or high idle while sitting for a few minutes or longer or only when driven ?

Will it cool a bit after you stop  driving after it heats up?

 Be sure your ignition timing is correct ,are you advancing the manual  spark lever after it starts .
If the timing is automatic, the timing can still be incorrect and start and idle o.k. so it appears.

Edited June 3, 2021 by Flivverking (see edit history)

[AL1630]

5 minutes ago, Flivverking said:

It could have 1/3 or more of the tubes blocked completely but water runs through open tubes fine .A radiator in such condition has a low capacity and can not cool at all.  
If the radiator holds a gallon and a half of water when unplugged clean..with solid plugged sections of tubes you may only have a gallon pushing through or worse.

The way to check for this is to run the engine and see if parts of the radiator are cold, right? Cold sections = plugged tubes.

 

Also, AllenWConrad, A handy tool to have diagnosing stuff like this is a laser/infrared thermometer gun. That way you can check things without risking burns.

Edited June 3, 2021 by AL1630 (see edit history)

[Terry Wiegand]

I think that I might be able to help you.  Back in the early 1960's my Dad belonged to the Hutchinson Regional Group of the Horseless Carriage Club.  There was a fellow in the group who had a very nice 1925 Chevrolet Roadster.  For whatever reason he took the radiator off the car and had the local radiator shop flush it out, back flush it and pressure test it for any leaks.  He put the radiator back on the car and he could not start the car and drive it much more than a city block and the engine was almost boiling.  He tried everything in the book to figure out what was going on.  To make a long story short, there was a restrictor plate in the top radiator hose connection that had been knocked out or accidentally removed.  The coolant was moving so fast through the radiator that it did not have a chance to dissipate the heat.  The little plate was put back in and the problem was solved.  You might check your radiator to see if that restrictor plate is there.  If that is missing, that could very well be your problem.  I hope this information will be of some help for you.

 

Terry Wiegand

South Hutchinson, Kansas

[AllenWConrad]

Terry exactly where would this restrictor plate be exactly?

[Terry Wiegand]

The little restrictor plate would be inside of the top radiator hose connection tube.  Please understand that I personally did not see this little plate.  One of the other guys in the group was telling my Dad about it after the problem was fixed.  I remember my Dad saying that the little plate was about the size of a quarter and that there was a hole drilled in it and that this was welded to the inside of the tube.  Its purpose was to slow down the coolant flow going into the radiator.  In other words it gave the radiator core the chance to do its job.  I'm thinking it wouldn't hurt anything to take a look and see if the plate is in there.  This could be a simple fix for an aggravating problem.  I was told once that the early Chevrolet guys all knew about this feature.  

 

Terry Wiegand

South Hutchinson, Kansas

[AHa]

Terry is correct. All the early Chevies had restrictor plates in the water tubes and over time the plates rust out and the water flows through the system too freely. They will not cool as a result. If memory serves the plate should have a 3/8s hole in it. I couldn't tell you where to look but from what you describe, I can almost guaruntee that is your problem. Any round plate with a 3/8s hole drilled through the center will work. Just cut one the size of your inlet or outlet and place it up against it and put your radiator hose back on and you'll be good to go. I might suggest making it out of stainless so it won't rust out again.

[George Cole]

A 3/8" stainless steel fender washer will work.  ACE Hardware has them in various outside diameters.

[AllenWConrad]

Update.  The washer seemed to work and it is running cooler.  But now it spits and backfires going down the road.  What is a solution for that?

[BearsFan315]

posted some info in your other post asking the same question  1923 Chevy supreme backfires and spits

[AHa]

This either means it is running too lean or too rich and I forget which is which. The other extreme is to have it cough in the intake.

 

Edit. I believe the backfiring is caused by the float being too high and or the mixture being too rich. I think I would take off the carb and blow it out good with carb cleaner and check the float height. It sounds like you have carb trouble. If these old cars set with todays modern fuels in them, the fuel can gum up the carb and it will not work properly.

Edited June 6, 2021 by AHa (see edit history)

[46 woodie]

I have heard of people using freeze out plugs, with a hole drilled in it. The reason for using the freeze out plug was because they could secure it with a hose clamp around the radiator hose.

[hwellens]

If you have a head gasket leak and some exhaust is going into the water, it will over heat fast. Just a thought as I have seen this happen.

[viv w]

Spitting and backfiring can be caused by a faulty ignition condensor. The condensor might have gone bad due to your overheating problems.

Other causes of overheating can be wrong heat range of spark plugs, a lean carburettor mixture or the motor sucking air through bad manifold gaskets or cracked manifold. Also check to see that vacuum lines to the wiper motor or vacuum fuel tank are connected properly and not allowing it to suck in air.

Viv.

[Mikefit]

I had a 20s Buick it would push out coolant then run hot there was a baffle in the top tank to defuse the water interning the baffle came loose and was laying on top of most of the tubes not letting water flow. 're attached the baffle problem solved