Cooling system flush

[aussiecowboy]

I have a 1930 Pontiac that was restored about 15 years ago, it was driven for a short while and then parked for years in a garage. The problem is the owner parked with the engine and radiator full of coolant, the water has slowly evaporated out of this and left a kind of skin of coolant scum behind. The engine is now overheating very easily. Is it safe to put a modern cooling system cleaner in our old cars or is there a better way?

[Guest]

A cleaner should not hurt anything but you have perhaps four causes of overheating. Are you sure that the car did not have an overheating problem before it was parked???

First: is you timing set correctly? If the timing is early or late it can cause overheating.

Second: is the packing on your water pump tight. If the pump is sucking air that can cause overheating.

Third: do you have a thermostat in the watermanifold housing, or a restrictor to slow down the flow. If the flow is too fast the rad dosn't have time to cool the water.

Forth: radiator.. if you have an "honeycomb" (6 sided cells) radiator, which was original to you car, it is very very hard to clean. The coolant tubes are very fine and the zigzag across the radiator. They can only be cleaned by getting some solvent to flow through them (virtually impossible to clean out mechanically).

If your rad has been replaced with a cellular core (square cells on edge) it is easier to flush as the tubes are larger and it is possible to remove the side tanks and to rod this core out.

I would consider trying a plain water flush. Take the lower hose off and direct water into the top of the rad just fast enough so that it dosn't overflow. Water is the most universal solute in the world and it might just do the trick after a few hours.

You might also consider knocking the core plugs out to be sure there is nothing plugging the water jacket.

FYI

I use a 195 degree thermostat and fill my rad to just above the inlet hose with a fifty fifty mixture of ethelene glycol or dexron and water (according to my manual once coolant come out of the upper tap the system is full enough). I have driven from -54 degrees to +117 degrees with my Pontiac (at highway speeds of 55 mph) for hours and have never had an overheating problem.

[aussiecowboy]

The previous owner assures me it has not had the problem before, he is a very pleasant elderly gent and I tend to believe him. The radiator is a honeycomb but a modern reproduction, cost a small fortune evidently.

I have set the timing but there would be no harm in checking it again, stranger things have happened. On the thermostat issue, I honestly don't know, I have not opened the housing since owning the car, will do so though. Any clues as to what make and model of thermostat will fit these? The water pump was replaced with a modern pump when the engine was rebuilt, maybe it is a little too efficient as you suggest.

I'll try the water flush before doing anything drastic I think.

On a side note, I had two brake drums out of round on this, I had them skimmed back to round and the machinist (a retired fitter and turner I use) complained it was the hardest material that had come across in many a year. They sure knew how to build them.

[Guest]

I use a thermostat from a 283/327 Chev engine. The new stats are too small in diameter. I was able to remove the non working bellows from my original type and use it and a piece of metal that I cut to the same dimensions to go on each side of the modern stat. I changed mine in 1962 to a 180 (165 was original) and then to a 190 and finally to a 195 when that became the normal for modern engines. I felt that if a modern engine ran better hotter so would mine and I believe it does. I fact if I add 3 gallons of diesel to 7 gallons of gasoline (with or without ethanol) it runs even better. No value in that today as diesel is more expensive than gasoline. The best mix is gasoline and kerosene but that is prohibitably expensive.

It sounds as if your original thoughts on the cause of your overheating could very well be right. Enough flushes should eventually clean things out.

My drums have never been turned in 499,000 miles. I was told by a usually reliable machinist that they were pressed steel and therefore could not be turned.

Good Luck

[aussiecowboy]

Your machinist was mostly right, they are pressed steel and can be turned but not easily, my guy had all sorts of rubber and rags duct taped around the outside to muffle the ringing sound. The end result was excellent though.

I'll order a thermostat and make up something to fit, cheers for the advice.

Another very old mechanic told me to set up an electric pump in a 44 gallon drum for the flush, use hot water and a mild detergent/solvent and keep circulating the water for 24 hours. Obviously this needs a strainer in the system. He swears that it will get a radiator like brand new, I might even give that go go yet.

[Guest]

Sounds like agood idea.

By the way do you know anyone in your area that has a pair of steering knuckles (spindles). I need two or else my engine rebuild is for nothing.

[aussiecowboy]

What is your time frame? I have purchased a shed full of Pontiac parts from an old guy and am slowly emptying it out a bit at a time (he is 4 hours from me). I can see probably a dozen front and rear axles standing up at the back of the shed but it will take me a little while to empty the shed to that point. Due to the layout there is no "shortcut" to get to them either.

[Guest]

My time frame is as soon as I can find a pair. I am told mine could be welded an am thinking of doing that but it would stil be great to have an original good pair. Let me know.

Thanks

Reid

[aussiecowboy]

I'll see what I can dig up. Just a thought though, are right hand drive and laft hand drive spindles interchangeable? I'm away from home at the moment so can't check.

[Guest]

Yes they are the same, it's he curved arm behind them that is different. In 26/27/28 left and right are different and different on left and right hand drive as well. 29 are the same either side and left or right hand drive. 30/31/32 are all the same, no difference as to side or drive.

Edited January 16, 2013 by Guest (see edit history)