I am relatively new to flatheads and I have a question concerning the cooling system. Not knowing any better, I filled my rad to the top. I learned that as soon as the colant heats up, it's going to dump on the ground. I have read to leave a couple of inches to allow for expansion, but what I am concerned about it if I run a little hot now and again and lose additional coolant, at some point I will not have enough coolant in the system. I was thinking about adding an overflow tank. What is involved to make it so it would draw the coolant back into the rad (closed system)? I have seen old radiator bags, but I don't just want to keep it off the ground to manually add it back to the rad. Any answers are appreciated. Thanks. 1950MERC
needs a sealed radiator with a recovery type cap that has a second rubber seal around the outside. the overflow tube goes from the radiator overflow tube (which is located between the inner and outer cap seals) to the bottom of the overflow container. when the coolant cools off again, it shrinks and creates a vacuum in the radiator, and "sucks" the coolant back in.
to add an overflow tank that allows the radiator to suck the coolant back when it cools you need a radiator cap for a closed system. what radiator do you have ? stock? most caps for closed systems are about 7-13 PSI.....not sure if your current radiator can handle that
So I take it I'm not just looking at a different cap, but also a rad with a different neck, since I still have a stock 50 merc rad? Thanks 1950MERC
your merc uses a 4 lb cap.....i wouldn't go any higher than that maybe you could take your current cap down to a real auto parts store and see if they can find a closed cap to fit
Skip Haney From Florida makes a pressure relief valve that fits onto the overflow tube on these setups. It's set at 4 pounds. This both increases the boil point and saves coolant by holding in the coolant during minor heating from expansion. Contact Skip Haney 941-637-6698 day or 941-505-9085 nites. [email protected]
You cooling system should only overflow the first time you fill it. The coolant expands and overflows as it comes up to operating temperature and it's operating level. It should stop there if the cooling system is working correctly. Heat gain after the first shut down might let some out but that should be the only time. The level will drop when it cools back down but will return to the top (operating level) when heated back up the next time you drive it. If it pukes every time it heats up there is something wrong unless you try to top it off every time it cools down. The engineers factored in the expansion and contraction of the coolant in the radiator. If you check the level when it cold it will seem low. Check it after it warms up and it should be right up there. Unless you want to run very high operating temperatures, your stock flatty should not need a recovery system. That's a relatively modern contraption to let the cars run hotter and cleaner for gas mileage and emissions. A coolant recovery system on an old car won't fix an overheating problem.
Thanks everybody. Tommy Everything you say makes sense. I just noticed that a few times after I first filled the rad to the top, the overflow dumped some coolant. I'm not sure how much though. I was going to see how much it took to fill again to gage how much I lost. My needle has never gotten all the way to hot, but I don't know if it goes all the way to hot, or how accurate it is. It settles down to just beyond midscale with the car cruising at around 50 MPH on somewhat flat roads. I'm just gun-shy of doing damage, because I have heard flatheads are notorious for overheating. The waterpumps are spinning and I just put new thermostats and coolant in. Maybe I'm overthinking this. Thanks again. 1950MERC
That is what I sensed in your question. My 51 Merc engine rarely gets over 180 while being cooled by a stock 32 Ford radiator. Don't believe the wives tales. I can't see any coolant when I check the level when it's cold. Don't panic.
Tommy gots it right on open type...it tells YOU where the level belongs. I've seen pics of Skip's valve--it's just a one-way. Modern sealed caps for no loss type systems all seem to be very high pressure, not good for olde radiators with large, unreinforced tanks If you want a closed system, here's my design, which I have not gotten around to building...so let's blow up your car for the test instead of mine! You're welcome!! Run overflow hose to bottom of a container, connect it to a small pipe threaded brass Tee fitting. Screw two low pressure streetrod residual brake pressure valves into the other two holes, one allowing flow out, the other allowing flow back to radiator. You'll probably want to use the lowest pressure one, I think 5 or so, and you want "in" one lower pressure than the "out", so whack the "in" spring til it has low seating pressure. This should work as an low pressure in-out recovery system, that or it will destroy your car or something.
Yes, I am using one of Skips valves and they are one way. Normally designed to be used on the old syle radiator necks. These necks have the overflow tube too low on the neck and the pressurized caps dont reach that area. The valve is clamped right onto the overflow tube and maintains the 4 pound pressure within the system. I have seen open systems loose more coolant during high speed runs at 60-65 mph for long distances than during normal 45-55 mph driving. (Note ..not from overheating) .The presurized system with the valve, I am using, stopped the excessive overflow during "the high speed bonneville runs."
I know this is an old thread but has anyone got a picture of one of Skip Haneys one way pressure valves? I can't find them on his website.
Have your overflow tube dump into a container instead of the ground. You will then know what was lost.
Well. I don't think it would be more than 12 oz. considering all the PBR cans I see clamped to the radiators!
I know this is not really answering the question recently posed, but on my 37 Chevy Ute (all stock 216 drivetrain) I converted the radiator to a sealed system, Required removal and soldering closed of the orig drain tube, and a different neck that is designed for the two seal type cap. Basically the neck has the tube connection that is between the two seals of the cap. I got tired of always having to add coolant and water, even after the orig fill and leaving expansion room. It would always lose a bit when driving. Now the sealed system keeps the loss to none.
The Jalopy Journal
