Coolant Level

[stan35]

Last year I noticed a wobble on the pulley of one of my water pumps. I removed both of them and sent them to Skips for rebuilding. After installing them back on the car I noticed that coolant was discharging from the overflow tube while driving. Skip then recommended his pressure relief valve. I installed the valve and that stopped the coolant from discharging while driving. However, when I shut the car off about a tablespoon discharges from the relief valve. Recently I experimented to see if the water will come to a level where it would not discharge. It seems it stopped discharging with the level just above the radiator tubes. It does not overheat and the gauge never goes above halfway. The car is a 1935 Cabriolet restored 2 years ago. My question is it safe to run the coolant at this level ? If not then either I will fill it to the proper level and live with it or install a overflow tank. All responses appreciated.

[dean333]

My 36 sought its own level, just above the tubes, where it stopped spitting out. Runs fine, no cooling issues. Skip did my pumps but I dont have the extra valve.

[satelite]

I run the water level on all my classics just above the tubes with no problems. The upper tank was designed to be an area for the hot water to expand. If you fill it to the top you will find that the water will push out of the overflow tube. If you are not comfortable with this you could add a recovery bottle (or tube) which all manufacturers did in latter years.
Don in SC

[Kube]

Originally Posted by satelite

I run the water level on all my classics just above the tubes with no problems. The upper tank was designed to be an area for the hot water to expand. If you fill it to the top you will find that the water will push out of the overflow tube. If you are not comfortable with this you could add a recovery bottle (or tube) which all manufacturers did in latter years.
Don in SC

Don is 100% correct. That top tank is, as he has stated, for expansion. Just "over the tubes" is correct.

[flatjack9]

Oh boy, GM will have a fit if he reads this. By the way, I run my 39 with the water just above the tubes. 20 years, no problems.

[estout81]

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Run my F-1 just over tubes and haven't added water in 2 years. Doesn't overheat!

[G.M.]

Originally Posted by flatjack9

Oh boy, GM will have a fit if he reads this. By the way, I run my 39 with the water just above the tubes. 20 years, no problems.

G.M. isn't having a fit you can run them with no water if you want. All my old Fords have either a 4 lb pressure cap that work or Skips 3 lb valve. Every one runs at 180 degrees or lower on 95 degree days which it is a lot of the time in SW Florida. These engines are made to run with 18 quarts of coolant not 13 or 14. More coolant and more coolant flow equals better cooling. I fill all of mine to within 3/4 to 1" below the top of the filler neck or over flow tube in the neck. The water remains there with lots of driving for a year or more. As for expansion below 200 degrees there isn't much and the large diameter long radiator hoses take this small amount of expansion. Others have posted the same results on this site. G.M.

[estout81]

flatjack9,
GM knows things we don't know!

[Ken Bull]

I drove my 40 PU for 19 years and it liked the coolant level 1" below the filler neck. My 36 Cabriolet will spit out any coolant more than 1" above the radiator tubes. So I guess one can say I let the system decide.

[G.M.]

Originally Posted by Ken Bull

I drove my 40 PU for 19 years and it liked the coolant level 1" below the filler neck. My 36 Cabriolet will spit out any coolant more than 1" above the radiator tubes. So I guess one can say I let the system decide.

Does that mean it's right??? G.M.

[G.M.]

Originally Posted by estout81

flatjack9,
GM knows things we don't know!

It appears that way. G.M.