Re: Model A Cooling System

Posted by Doug Linden on Sep. 05, 1996 at 14:44:57

In Reply to: Model A Cooling System
posted by John Young on Jul. 13, 1996 at 11:05:58

: When running along, coolant is discharged out of overflow tube in radiator. Radiator has been rebuilt. Water pump has been replaced. Checked system to see if engine compression is getting into radiator system. Seemed okay. Seems to happen after engine is totally warmed up and at higher speeds. Got any ideas?
John - This is one of those areas that lots of information has been published and if you have access to the "Restorer or Model "A" News" you will undoubtably find a lot of hints.I can't say for sure what may be causing your problem but it can be cured.The fact that coolant is coming out of the overflow tube means that at least you have water circulation.
I see you said the radiator was rebuilt?Was the radiator cleaned professionaly?If not I would have that done first.It may not have the flow rate that it needs to work properly.My raditor is in tip-top shape and it will completely drain out in less than 4 seconds.Also, have the overflow tube checked.They sometimes develop cracks below the water line and will allow coolant to drain.
The amount of water the pump puts out is very large.The condition of the impellers and the clearence between the impellers and the cavity in the head has an impact on water flow.You may have too much and at high speeds it may be necessary to grind off some of the impeller fins.
Check you timing again to make sure it's not retarded.Also what kind of spark plugs are you using.They may be running too hot as well.I would use a W18 if your not using the 3X.
You might also want to try a thermostat.In addition to keeping the engine at a better operating temperature it will also act to slow the water flow do slightly.One other benefit is that the hot water will help flush out any crud that is stuck in the block.Most of us in our club use one.
If all else fails you could go to a coolant recovery system.I have one on my Model A and after traveling over 2000 miles on our trip to Toronto and Dearborn from Boston I had zero coolant lose.ZERO!That included highway travel at over 60 MPH during Jul..I have a temperature guage in the upper hose and the temp never got over 200 degrees and that was only under heavy load going over mountains in New York.
So keep looking, I'm sure you'll be able to get it running correctly.

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