Help. Loosing Coolant

[DanMcSign]

Hello
I guess I need to jump in here one of these days. I have a '36 Roadster that I have brought out of storage after nearly 40 years. After going thru the carb and distributor, having the water pumps rebuilt by Skip, cleaning the fuel system etc. she fired right up and seems to run smoothly. The problem is it looses coolant after just a few miles and cannot figure out where it goes. There are no apparent leaks. I do get what I hoped was condensation out the exhaust but maybe it's bad news. The liquid does not have the green tint of the coolant. What should I do next?
Thanks in advance for your input.

[rotorwrench]

It could be a head gasket leak. These old engines also like to crack in all sorts of places due to freeze up or overheating. You might check the spark plugs and look for clean ones or wet ones. They sometimes crack in the valve pockets so coolant could go right in the exhaust from there. I've even seen them crack inside the center exhaust port where coolant will just poor out the exhaust port. If you can nail it down to a specific side, you can just pull the head on that side and check it but I'd pull both heads anyway just to use both of the new gaskets that come in the top end set.

[JSeery]

I would try a coolant sealer first and see if that helps.

[Lawrie]

Also take the tank off the top of the radiator,my 33 lost water ,could not see where,the rad was 75% blocked.that fixed it.
Lawrie

[JSeery]

Good point! be sure the radiator is open before adding a sealant.

[rotorwrench]

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Ya, that can be a problem with bar's leaks too. It can further plug an already gummed up radiator. If it's an engine block leaker and the radiator is otherwise clear then it might work OK though. You can set up a catch bottle for the radiator overflow using an old soda bottle and see if its barfing out there.

[petehoovie]

Is it that you 'topped off' the radiator? If your cooling system is un-pressurized, it will puke out coolant it doesn't want/need and find its own level in the radiator - they never remain brim full/topped off for long....

[CaliforniaBorn36]

I second rotorwrench's idea. Take a soda bottle and a few twist ties and mount the soda bottle at the end of the overflow tube. I did this with my '36 and can always catch some overflow. Pour it back in the radiator and the level is as it was before. Since it does that, I run a little less coolant and the engine does not overheat or overflow. Found it's own level which is just barely at the top of the tubes.

[DanMcSign]

Thank you guys for giving me things to heck out. I'll report back with findings in a few days.

[Flathead Fever]

If its a head gasket the engine will usually miss when you first start it and then idle fine after the water burns out of the cylinder. It will smoke out the tailpipe until it is burned off. We use to pressurize the system and then go to lunch. Later we would pull the plugs and crank it over. If it was head gasket the leaking cylinder would shoot water clear across the shop.

I had one of our driver's bring a V10 F450 into the shop blowing white smoke out tailpipe, really bad. I had him park it along side the shop. A couple hour later I hopped in to it to bring it in the shop. I cranked the engine and it rotated about once and then it went clunk, it hydrolocked. You know those small little high torque starters they make these days. They have so much torque they can bend a connecting rod if the piston cannot move.

There is another test we use to do. This one is a very reliable test if you see steam coming from the crankcase. We called it the dipstick test. Carefully remove the spark plug. Now remove the oil dipstick and insert into the spark hole. If you can check the oil level in the pan you have found the problem. I had several engines fail the dipstick test. You might laugh but it saves you from tearing the engine down any further. You just start looking for another one.

[Veeder]

I may have missed it but have you done a compression test on each cylinder?
bob

[G.M.]

Originally Posted by DanMcSign

Hello
I guess I need to jump in here one of these days. I have a '36 Roadster that I have brought out of storage after nearly 40 years. After going thru the carb and distributor, having the water pumps rebuilt by Skip, cleaning the fuel system etc. she fired right up and seems to run smoothly. The problem is it looses coolant after just a few miles and cannot figure out where it goes. There are no apparent leaks. I do get what I hoped was condensation out the exhaust but maybe it's bad news. The liquid does not have the green tint of the coolant. What should I do next?
Thanks in advance for your input.

This is normal. The 144 24" tubes in the radiator will not let the coolant
free flow through the radiator. As a result the coolant takes the path of
least resistance which is out through the over flow. This problem was
over come on later years when a 4 lb pressure cap was install. The
pressure cap closed the over flow tube allowing coolant to be pushed
through the radiator tubes. This also allows the full 22 quarts of coolant
to be installed, the more coolant in the system the better it cools. If
you have any questions contact Skip. On your engine you need to install
a small plastic recovery bottle on the top of the left frame rail. Have
the hose from the over flow tube go into the bottom of the tank. Excess
coolant will go in the tank and as the engine cools and drops below 155
degrees a vacuum in the engine draws the coolant from the bottle back
into the engine. You also need to add a rubber gasket in the radiator
cap or it will leak coolant. G.M.

[Graeme / New Zealand]

I've just had a problem with my radiator spewing coolant out that leaked on to the front fenders after a trip out and up and down a steep hill. Took the radiator cap off and found there was no spring effect when I tightened it down. A new cap arrived in the mail yesterday, should cure the problem. My system is 4lb preasurised.

GB