Where does the coolant go ?

[35 coupe]

Took my 35 coupe for a nice stretch today, around 60 mile round trip. Air temp was 75* car was running great, trying out a new fuel pump. Ran up thru mountains and winding country roads, did not overheat, temp gauge right where it always is, no backfires, nothing wrong. Engine is original, never rebuilt, model 48 carb, original radiator, been professionally cleaned, never leaks on my garage floor. It needed about a gallon of fluid in radiator. I know some goes out the overflow, its inside the neck, especially on right turns, when it is full. Exhaust pipes are nice and dry, no wet soot. original cap on radiator with new fiber gasket. Where does the fluid go, does it expand that much to push it out the overflow. Thanks

 

[B-O-B]

Get yourself a overflow container & a Skips 3# check valve.

 

[keith oh]

Check compression for a low cylinder indicating head gasket leak or small crack in head or block. Check spark plugs for an especially clean one as water in combustion chamber causes a very clean burn. Carefully look in each cylinder for one with very clean valves and chamber which would also indicate a leak. Before I would start tearing it down I would put a bottle of Barrs pellet stop leak in it to stop any possible small leak. You might get lucky.

 

[Lawrie]

I had a coolant leak problem on my 33,it would use 3-10 litres on a long uphill pull,then none, then some more on the flat.
I looked for ages to see where it was going,couldn't see it.
Took the engine out,put new head gaskets on,went away the same thing,only this time I stopped at the top of the range and had a look,I saw some wetness on the right hand hood side,so later that day at a campsite I changed the two water pumps(new ones),fingers crossed it has n not used any since,about 600 miles.My thinking is the fan blew the leaking coolant in a mist and I could not see it.
My old mate made a good point,he said if it was an old bomb with rusty water in there it would have left a stain to see,but nice clean water and coolant did not,
lawriei

 

[35 coupe]

I have new water pumps on it, both were leaking so I just changed them over the winter. If you had a head gasket leak, wouldn't you see white smoke coming out exhaust ?

 

[wga]

There is a product available at NAPA - Block Tester. The fluid changes from blue to
yellow if there is an exhaust leak. Do you have an independent shop where you
can check for exhaust gases in the coolant by using the 'smog probe' just inside
the radiator filler neck

 

[G.M.]

If it's not in the oil or coming out the exhaust it' coming out the over flow. Put a rubber tube over the bottom end of the over flow tube and sit a plastic bottle on the left front frame rail up near the radiator. Cut the hose on an angle so it can't get blocked and put the hose down in the bottle and I'll bet that's where your water go's.
You don't need the bottle with Skips valve. To stop it get Skips 3 lb valve and put a rubber gasket in the cap, the fiber won't seal. G.M.

 

[DICK SPADARO]

My take on this is you are spinning the engine over to fast. if you are driving at high engine rpm and the radiator does not full flow the water pumped by the water pumps builds up in the upper tank and escapes thru the over flow tube to be lost. Alot of people think that they are over heating but in reality the radiator is not circulating water fast enough and is burping water. If you want to check that scenario fill the radiator as normal and take the car for a slow spin not going over 45MPH and see if you are loosing water if not your radiator needs to be cleaned or you need to cut down the engine RPM with a different gear set for high speed driving.