VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 Overheating..Part 2

After weeks of trying to get my newly acquired (Jan 08) 36 coupe running (over-heating problem mostly), I finally gave up and took it to a recommended "old time" mechanic who's shop is filled with cars of the past. I supplied him with an unused NOS radiator that I bought on ebay, and let him go at it. The radiator had a small pin hole (probably from being moved over the years) and was sent out for repair and then installed. The block has been flushed and "flow tested" and the radiator is flowing great. I had previously replaced the water pump and noticed that the baffle behind it was good and still in place. The car is still overheating!!! I don't recall ever seeing any sepage from the head or any water/antifreeze in the oil but the shop is going to do a compression test all the same. Does anyone have any suggestions, based on past experience, that I can pass on to the shop.

A couple of things; the 36 engine does not have a baffle plate as the back area is cast in the block. Make sure you have a 36 water pump as a 35 will fit your engine but has a thiner vane pump. Is your engine timing correct? Retarded timing will overheat an engine. You can have part of the block and/or head plugged with crude/rust and still have good flow. A tight engine will run hot. If you haven't check the gauge for calibration, pull the sensor bulb out of the head and place in boiling water and see if it reads correctly.

Check the fan belt tension and have them analyze the coolant for exhaust gasses make sure the exhaust pipe/muffler/tailpipe has no mouse nests plugging it also. Let us know what you find.

The problem is the cooling systems on the Standards are marginal at best new from the facrory. To maximise the potential of this inadequate system try converting to a pressurized system and attaching an over flow tank. Don't exceed 12 pounds as original radiators are not build to run under pressure but 12 pounds won't hurt. The only surgery required is replacing the originsl filler neck and cap with modern ones. The purists may not like this modification but you can stop carrying that vintage canvas water bag on your front bumper guard. No front bumper guard? Then use baling wire. Now that is an authentic accessory!
In 1937 overflow tanks were intrduced and are available in ebay from time to time. This system requires no pressure and simply collects the overflow coolant and returns it to the radiator when cooling occurs. Not correct for 1935 but I have not been busted on the one I have installed....so far.

Bob:
You mentioned a few things that are somewhat subjective. The block was 'flushed' and the radiator 'flows great.' There can still be crud in the head and block that flushing can't remove. A good radiator shop should be able to quantify the flow rate using their equipment. I had a radiator with some blockage that was tested at only 15 or 16 gpm whereas a NOS flows at more like 20-22 gpm. Makes a difference.
Hope this link works: https://vccachat.org/forum/ubbthreads.php/ubb/showgallery/Number/118898
That's my '35 engine with a good bit of rust blockage in the block and head...after being 'flushed' several times. I don't think the common commercial cleaners were meant to dissolve 60 or 70 years of accumulated rust!
Your '36 engine has a larger cooling capacity (5 quarts larger) than the '35 but still can have rust in all the wrong places.

Bob,
I went through the same things you have on my `36 Master Town Sedan. For years it would over heat when driving over 40 mph and didn't like prolonged idling. After replacing the water pump, having the radiator cleaned and many engine flushes, I pull the head off to check the water jackets. The head was so badly corroded from 70 years of rust that I fished two handfulls of metal chucks out of the head. Some were as large as a quarter and the rest too large to pass out of the head (My flush attempts had removed most of the smaller stuff). Obviously the various water jacket passages were being blocked by all this stuff. I found a good '36 head and had it rebuilt. The car runs great now, I can push it to 50 to 55 mph and it stays under 180 F. It only gets over 190 if I'm pulling a hill over 40 mph but then cools back down to it's normal temp of around 170. Oh yes, I put a 160 F thermostat in it and it has the original 4.11 rear end. The head isn't too bad to pull. If you don't have guide pins, get some all-thread the diameter of the head bolts and cut four pieces long enough to screw into the block near the four corners to help guide the head off and on.