'29 A Town Sedan, over heating

[Ribbon clerk]

Runs for about 10-15 min and overheats. Put new radiator cap with thermometer on and after 10 - 15 min of normal driving it boils over and the temp shorts to the top of the thermometer.

[Ribbon clerk]

That should be "SHOOTS" to the top of the thermometer.

[Wick]

Do not fill radiator within 1" of the top. May want to drain and refill the system.
If it still overheats then we need to know how some history behind the vehicle.
Wick

[Mulletwagon]

Overheating that fast sounds like a flow problem. Are you sure the radiator is not clogged ?

[Railcarmover]

Have good results hot water pressure washing out radiators with degreaser chemicals..

[30 Closed Cab PU]

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Treat with a detergent like dawn and backflush radiator of possible grease oil.


Do the detergent 1st, Then a treatment or 2 of thermocure, rust 911, or evaporust - Back flush through the radiator. Detergent 1st, these products are poor at flushing grease/oil. then before running add an upper hose coolant filter like a Gano. Do not want anything that breaks loose clogging up the radiator.


If still an issue try shooting the radiator tubes with a IR temp gun, if you find cooler/cold spots, tubes are partially or totally plugged.


If still overheating/no improvement have radiator rodded out at a radiator shop.


Flow testing only works on radiators that are very bad, And sometimes testing at radiator shops can be false positive/thinking the radiator is ok.
A radiator can flow ok, but poor fin contact with the tubes due to age decreases a radiators ability to cool sufficiently.


If your radiator is really old, may be time for a new one. or a core replacement.


When I back flush prefer to back flush into a large plastic tub to see what comes out. The above products typically kinda dissolves rust scale, but you may see a few flakes and some grit.


If you research more and use white vinegar, be aware it can remove the grease in the original design type water pump causing the solution to leak and get all over. After the last treatment of white vinegar, do a treatment of baking soda/water to neutralize the acidic content of the white vinegar.
Simple flushing/backflushing with water is not good enough. This is similar to if you splash/spill battery acid, just a weaker concentration

[whirnot]

As Wick said above make sure it isn't too full the motometer measures steam, not water temp. It should be just above the core. If there is too much water it will look like it is overheating and then puke out the excess.

[steve s]

get a new radiator and be done with it.

[loubob]

X2 on above post.

[1crosscut]

Get a meat thermometer and test the temperature before buying a new radiator.
Moto Meters are a neat accessory item but not usually very accurate.
You/we need to know for sure what the temperature is before going too much farther.

How is your timing set??
If it is retarded it will cause overheating.

Had a friend purchase a new radiator because his car was overheating similar to yours.
I set the timing correctly before he installed it and he was able to send the radiator back. Saved a lot of $$$'s.

[30 Closed Cab PU]

Originally Posted by steve s

get a new radiator and be done with it.

If you do this, clean out the block and then run a coolant filter in the upper hose, would not want to plug up a new radiator.

[Wick]

I also use a heat reading gun to check for a clogged radiator.

[Ribbon clerk]

Thanks for all of the help. Will let you know how things come out.

[Ribbon clerk]

Sorry this has taken so long to get back in the forum; had a wedding to pay for.


Have pulled the radiator and filled it with white vinegar and let it set for about 5 days then drained it and back-flushed it with water. Had the radiator flow tested and pressure tested - both OK (but since this is not a pressurized system, does that matter?).
Also removed the water pump, plugged that port and filled the engine with white vinegar, let it set for about 5 days, then drained it and back-flushed it with water - 3 times (that's another reason it has taken me so long to get back here).
Additionally, I re-assembled everything but left the top hose off and filled the radiator and engine with water, started the engine and, at idle, very little water was pumped out of the return port. As I revved the engine, the water pumped out much,much better.
I reconnected the top hose and it still over-heats in about 20 min at idle. I assume that over-heating is when it boils the water out, right?
I am thinking that my next move will be to remove the head, the pan, and whatever else I can to get to the water ports and try to "rod" them out.

Yes, No ?????

[Ribbon clerk]

Also, as history, prior to this spring ('19), the car had not been started for about 20-25 years. As to the cooling system, it had antifreeze in it. (I have already drained and flushed the fuel tank, rebuilt the carb, changed oil, trans and differential fluids.)


Someone mentioned that the timing may be off. But I used the little piece in the front and timed it that way, besides the spark advance lever changing the timing, so how could it be that much out of time?

[ryanheacox]

Originally Posted by Wick

I also use a heat reading gun to check for a clogged radiator.

Yup, can even feel around with your hand for the cool(clogged) spots if you don’t have an IR thermometer.

[Ribbon clerk]

Doesn't the spark advance lever give/adjust the final timing?

[ryanheacox]

Originally Posted by Ribbon clerk

Also, as history, prior to this spring ('19), the car had not been started for about 20-25 years. As to the cooling system, it had antifreeze in it. (I have already drained and flushed the fuel tank, rebuilt the carb, changed oil, trans and differential fluids.)


Someone mentioned that the timing may be off. But I used the little piece in the front and timed it that way, besides the spark advance lever changing the timing, so how could it be that much out of time?

If you timed it by the book and run with the lever at least halfway down I would doubt it’s your timing.

[Dirtrack49]

You need to take a laser temperature gun and check the top core of the radiator and see what temperature your getting. Maybe somewhere between 150 to 200 degrees? After that, check the bottom core and see what you have. Maybe 110 to 140 degrees? If that is the case, you are simply overfilling the radiator and it is barfing out the excess.
You must remember that this is a thermo-syphon (BARF) cooling system with a water pump hung on the engine to assist.
My 1926 Model T thermo-barf system without a water pump, cools oh so well. It is even a three tube crap for a radiator from the era. Everyone tells me that it can't possibly work, but it cools as good as the day it was born.
Tom L.

[Dirtrack49]

Just saw your post about having antifreeze in the vehicle. How long was the antifreeze in before cleaning everything out?
I have a Mercedes 230SL that had been sitting for over 15 years before I got a hold of it. The antifreeze had turned to acid and ate holes into the thermostat and water pump housings.
If that antifreeze has been in there for a real long time, possibly, your cooling system is all plugged up from corrosion.
Tom L.

[burner31]

Fill your radiator with vinegar and drive around for about a week or so you'll smell like a Russian restaurant but it does a very good job when you drain it do not get any on your paint and make sure you flush with baking soda

[Jacksonlll]

You say the radiator was flow checked. I bet not. A good radiator should flow about 36 GPN.
Torque your head. Could be a leaking gasket, but very likely, your core is plugged. Get a new one. If there is no flow in a tube, you can’t clean the tube no matter what you flow on top of it.

[1crosscut]

We still need to know if you are actually overheating??
Get a thermometer and find out for sure what the temperature of the coolant is.
To me it doesn't sound as if you are really sure the timing is set correctly. The simplest way to do so is to use the inexpensive NewRex timing wrench to set your timing.
Also you need to make sure your spark advance lever travels fully side to side in the slot on the distributor before setting the timing and then make sure the spark lever is fully in the up position when you set the timing.
Putting vinegar in the radiator and the block will help with getting some of the rust out but what if grease build up from someone in the past putting too much grease into the water pump is the problem?
This time around pull the radiator out and pour 1 gallon of undiluted Simple Green into the radiator. Slosh it around several times a day for a few days and then flush it out. I think you may be surprised at what you get out of it. Of course to do this you will need to close off the upper and lower outlets on the radiator with some inner tube material or such held in place with a hose clamp. Also you will need to plug the overflow tube too.

[Gerald1961]

I agree to JacksonIII. Check the timing, then the head nut torque first. The old bolts stretch and need retorqueing.

I had the same issue recently after a 35 mls trip with 45-50 mls/h. Suddenly the engine overheated and- strongest indicator for the head gasket- even maximum enriched GAV didn´t cool down the engine. after that, scrutinize the radiator deeper.

[Ernie Vitucci]

Good Morning all...For an engine that has not run in years, the car may have been set aside because it overheated. Head gasket leakage can be a problem between cylinders
allowing heat to end up in the cooling system. Drain the engine, remove the head, study it for pin holes that can be allowing water to leak around the gasket. I have seen some heads that have become poras (sp) and cause over heating. Let the engine dry out for a day or so and then vacuum through the water channels in the block and then use compressed air and blow down into the block and all sorts of junk may come flying out. I once did this on a block and it turned all the air in the shop orange. Check the head and block for flat and then use a new BEST gasket and carefully torque it down according to the sequence and pounds feet in Les Andrews book. Good Luck...Ernie in Arizona

[DKnapp]

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Sounds to me that you may have a head gasket leak.

Fill the radiator to where you can see the water and start the engine. If you see bubbles coming up the water in the radiator you have a head gasket leak.

That hot air entering the water system will never be cooled enough even with the best radiator and a perfect cooling system.

Easy check - takes five minutes. First thing I do after replacing the head.

[eagle]

If it was my problem here's how I would address it. 1st check head torque. 2nd make sure your timing is correct, quick test is run it down the road at a good pull, if you pull the lever down all the way you'll hear the engine ping, then lift it up until the ping stops, thats where you want to run it. 3rd, use a thermometer to actually see the temperature. If it still is a problem then time to repar or replace the radiator. Some people claim that the Model A has a weak cooling system and you just have to expect issues now and again. I dissagree, if all is good it will not boil even going uphill on a very hot day. Same for the brakes, if they are done right they do a very good job of stopping the A. Lots of cars out there that people put up with poor performance from, simply because they have low expectations. Keep working through the issues, you'll soon have a very reliable car.

[Conaway2]

I suggest either taking it to a shop familiar with Model A radiators, or just buy a quality new one. I never had any luck with my own cleaning fixes. I just had the radiator on my ‘31 deluxe roadster professionally cleaned and repaired for $125. Solved my over heating problem and I no longer worry about it.

[Tom Wesenberg]

Originally Posted by Conaway2

I suggest either taking it to a shop familiar with Model A radiators, or just buy a quality new one. I never had any luck with my own cleaning fixes. I just had the radiator on my ‘31 deluxe roadster professionally cleaned and repaired for $125. Solved my over heating problem and I no longer worry about it.

There aren't a lot of GOOD radiator shops left, and it sounds like you got a fair deal on the price. Where is this shop?

[30 Closed Cab PU]

How are things going?
One other tidbit of info, had this happen to me. After struggling for a couple of years flushing/backflushing treatments, with the help of the Barn discovered I had an aftermarket 2 tube row core radiator. Except for Brassworks, 2 row cores cooling capacity is undersized. If you have a 2 row, replace it with a good 3 or 4 row core radiator.


In addition to the idle overheat, my truck also overheated in outside temps 80 degrees and above at 35- 40 mph after 10-30 minutes.