VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1940 - Temperature Problems

Temperature Problems. Thought i fixed them, but...
First i detected after reading the Manual, that there is not enough water inside. Because there was an air bubble inside and after driving, the radiator every time was empty (cant see water)
Filling complete with water, the temperature was better. But every time the water pressed out to the overflow on the Street.
Than installed a 5 Quart canister with a hose from the overflow, to save the water.
Today, before start a tour, filled up the radiator and the Oil (missing 1 Quart) for a good temperature. The first 15 Miles everything was fine, average speed 55 mph, Temp near 180, Driver keeps Smiling.
But then the temp goes step by step in the red Section.
At home checked the canister and was almost full. The Radiator pressed out about 3-4 Quart! Not good for the Temp. After refill everything was fine again. What is wrong? So much water to the overflow, why? The cap is a none pressure. I´ve got a overflow tank kit from chevs,but not installed yet. Is that the solution for the problem or should install a pressure cap?
When i look in the Radiator the water is bubbling very much coming from the thermostat?!
At the Moment must stop every 20 Miles to do the hot water from the canister back to the radiator.

An overflow tank should ot be necessary under ordinary conditons.
The radiator neck on a 1940 is not designed for a pressure cap.
You have either a bad head gasket or a cracked head.

Why this?? Bad gasket there must be oil in the water or white smoke from the exhaust...?!

if you have gasket break between cylinder and water jacket then air in water only . A radiator place can check for cylinder air in cooling water or some mechanics can do the test . What condition is the radiator ??

you may be able to fix those oil leaks while you are at it ..

Ollie

My first guess is the same, head gasket or cracked head. Air in cooling system from water pump is possible but not likely based on the description of the problem.

The Radiator Net comes new in 2012. Next Time will take a video from bubbling...

compression test might show you the way also .. warm up first..

Now here is the Video

You are pushing air into your water system...Head gasket or water pump..Save your money on the pressure radiator cap..won't help.

Or through a crack in the head....compression. Not too unusual in a 1937-1940 head.

I VOTE BLOWN HEAD GASKET . FRANK

Hello friends,
sorry, I change to german language now, ist more easy for me and André is a german pal in germany.
Hallo André, uff, das Video ist ja dramatisch! So sollte das nicht aussehen! Was ich Dir raten kann: Gute Werkstätten haben Messgeräte, mit denen sie Auspuffgase im Kühlwasser nachweisen können. Sollte bei so einer Messung Abgas im Kühlwasser zu finden sein, hast Du eine kaputte Zylinderkopfdichtung oder einen Riss im Zylinderkopf.

Wenn alles in Ordnung ist, darf es niemals so etwas geben wie in Deinem Video zu sehen.
Falls Du eine Zylinderkopfdichtung brauchst, ich habe noch eine im Keller und ich kann leicht welche aus USA besorgen, weil Freunde und Kollegen so ein Teil leicht als Reisegepäck mitbringen können.

Viele Grüsse
Stefan

Hi,
today tested the Compression. Found in a Manual, should be 112lbs?!.
have between 80-90 on five Cylinders but the first, near the waterpump !! has only 60. Longer starting could bring him near 70, but not more. With some oil in the Core Hole, no change. So the piston rings should be ok, puh.



by the way, the sparks looking good, but is that right J-8?? Read something about j-11 in the 1940??

Adding oil to cylinder and no improvement indicates a bad valve.
A compression check will not find a problem like a cracked cylinder head as the crack is almost air tight.

Chev Nut is right, the compression staying close to the same indicates the rings are not the cause of the reduced reading on 1 cylinder. It does suggest leaking valves or head gasket. The best method I have found is cylinder leakage test but this is rather complicated and will only tell you that the head needs to come off which you already know.
Tony