Hi,
I recently had the head rebuilt on my 33 Master 206c.i. After reassembly, flushing, and filling the coolant I have a concern. When driving and the coolant comes up to temperature, it rises to the level of the overflo tube in the top tank. When cool, it drops back to a lower level as expected.
My question is, how is the air purged from the head when refilling the coolant? I filled coolant thru the radiator and the level rises from the bottom, thru the block. Does this remove all the air from the head passages?
It seems the level changes a lot from temperature / expansion. I'm concerned that there may be air trapped in the head.
Thanks in advance for any info you may provide.
Doug
Typically the coolant will find its 'happy level'. The ideal situation is for the cold level to just be covering the radiator core.
i expect any air in the head has been burped out after a couple of run cycles if the engine reached operating temperature and did not overheat.
Sounds like you are exactly where I always aim to be.
I like to see as much coolant in the system as is practical, so I like to see the coolant right about at the overflow point when the engine is about as warm as it's normally going to get.
Then just note where it goes down to when it cools off and maintain it at that cold level.
On a side note to this conversation I was wondering if anybody saw the latest Filling Station newsletter where they talk about cooling problems on 1918 - 1936 cars. I get the fact they are trying to sale their wares but the part that caught my attention was when they stated that cars of that era should "not" have anti-freeze protection in them. Mostly , I guess since they are not a pressurized system, should be driven with just water and a water pump lube. Anti-freeze should only be added at the end of the driving season and mostly for storage time. Just curious what the train of thought is out there. Agree? Disagree? Here's the article (about the 9th paragraph down).
https://www.fillingstation.com/cooling/
From my experiance I disagree.
I've ALWAYS had ethylene glycol antifreeze in my '29 and never had a problem.
I know others have, but not me.
The article says the problem is due to, and can be cured with the water pump.
That implies that if you have a packing style pump in very good condition, you shouldn't have a problem either.
I live in Canada, but I know that it DOES freeze as far south as Florida and Texas.
Experience here has shown that even the SLIGHTEST frost can and will severely crack a block or head.
In fact, for some reason, more engines seemed to suffer cracks when there was 1 degree of frost, than when there was 4 or 5 degrees of frost.
Some thought that it was because the 1 degree frosts often lasted for hours and had more time for the ice to expand, which did more damage than a sudden but short 4 or 5 degrees.
Long story short, I NEVER trust leaving water without antifreeze in any engine.
Interesting that they say the lack of a thermostat with anti freeze can cause foaming but their sealed pump cures all.
I might try a stat in my 31 to see if that helps the foaming.
Dave
I always use antifreeze in all of my old Chevrolet cars and always have with no issues! I would not run straight water for any length of time. Antifreeze has anti rust and corrosion additives plus it raises the boiling point of the coolant! I currently have a '33, a '37, and a '48 all have had permanent antifreeze in them for the last 40 years with no problems at all! Before that I have had a '31, a '32, and a '42 and used antifreeze in them also with no problems.
The problem with foaming is air getting into the cooling system. It causes bubbles that with glycol antifreeze are more stable than just water. The glycol lowers the surface tension just like soap. So the real solution is to eliminate air getting into the coolant. The most likely is air being drawn into the pump past the shaft packing or seal. In addition to forming bubbles (foam) which pushes out coolant. The air also reduces the internal engine cooling.
If your vehicle tends to loose water when the engine speed is reduced it is a good sign that there is air in the system. The running engine creates a little pressure in the cooling passages keeping the air bubbles smaller. As the engine speed is reduced so is the pressure resulting in increasing size of the bubbles which take up space for coolant and therefore push coolant out.