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Engine running, water overflowing with increased rpm

Started by Stinson, March 22, 2010, 11:39:34 AM

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Stinson

Well, it appears that I can run my '37 V-12 in the garage for 30 to 45 minutes and no problem, stays in the white and have done this several times. But, if I raise the rpm the radiator overflows, still in the white. What is going on? Bad water pump? Blockage in the engine? This is a new copper core radiator. Not sure about the thermostat to the shutters.
Ty Stinson
Ty Stinson
'37 Cad 8519 Touring Sedan V12
CLC22330

Otto Skorzeny

When you say it overflows, do you mean it's boiling over? Does this happen with the cap on or off? Make sure your cap is the right pressure rating and that it's working. Too high pressure rated cap can cause over-heating.

Don't trust the dash gauge until you verify the actual temperature. Hook up a real temp gauge to the engine where the sending unit goes and see what happens.

Do you have an infrared thermometer?
fward

Ask not what your country can do for you, but what you can do for YOURSELF

HUGE VENDOR LIST CLICK HERE

35-709

I think this is normal, when you increase the RPM the water is moving faster and tends to rise higher in the radiator.  Leave the water in the radiator at the level it settles at after you have run the engine at higher speeds.  This should be the maximum fill level for your car. 
Geoff N.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Mark Lowery

Quote from: Otto Skorzeny on March 22, 2010, 03:51:29 PM
When you say it overflows, do you mean it's boiling over? Does this happen with the cap on or off? Make sure your cap is the right pressure rating and that it's working. Too high pressure rated cap can cause over-heating.

Don't trust the dash gauge until you verify the actual temperature. Hook up a real temp gauge to the engine where the sending unit goes and see what happens.

Do you have an infrared thermometer?
Otto, or do you prefer Forest?
I agree w/ the idea of checking the cap, but disagree w/ the comment about "too high pressure rated cap causing over-heating" per se.  The reason caps are set at various pressure ratings is to allow the boiling point of the coolant to be increased.  A higher pressure cap actually allows an engine to run at a higher temperature w/o boiling over and hence to cool more efficiently.  The danger in running too high of a pressure rated cap is simply that some of the components (hoses, radiator core etc.) might not be up to containing the pressure once the engine gets to the new, pressure induced boiling point. 

The infrared thermometer is a handy device around the shop for all sorts of uses.  Have used one to detect a bad injector on diesel engines (no firing, no heat) and other clever things.  Heck, if it has the right range, you can even use it barbecuing!

Mark Lowery, CLC#25216

The Tassie Devil(le)

I am with Geoff on this one.

Running the engine with a full radiator, and the cap off will always cause the level to rise when revving the enginew, as the Water Pump is trying to force more water through the engine, and therefore, with the cap off, the least resistance is there, at the top.

I am not sure what pressure your engine requires for the cooling system, but as you don't have a recovery tank installed, if it is original, then the coolant level should be set at what is lefty in the Radiator, AFTER the engine has had time to totally cool down to cold.

If you refill to the top, or above that low mark, then it will ALWAYS overflow.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Otto Skorzeny

#5
Mark,

Each pound of pressure in the system will raise the boiling point of water by ~3 degrees. That's how pressure cookers work on the stove.

If the cap pressure is too high, overheated water cannot vent from the system. It stays in there getting hotter and hotter at the same time increasing the pressure until the hoses break or the heads crack or whatever.

So you're right in that he cap might not be the direct cause of the overheating problem but it can make the problem worse by forcing the water to get even hotter than it already is before being expelled from the system via the overflow hose or blown hose or gasket. .

fward

Ask not what your country can do for you, but what you can do for YOURSELF

HUGE VENDOR LIST CLICK HERE

The Tassie Devil(le)

Otto,

Ty isn't saying that the water is too hot, just questioning the increased flow into the top of the Radiator when he gunns it.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Stinson

Good morning,
Last night I ran the engine for over 30 minutes at idle. Water continued to drip out (1/2 to 1 pint) of the overflow tube and the guage stayed in the center of white. I think the 4 pound pressure cap is not seating correctly or is too short because when I grasp one of the radiator hoses and squeeze it, water flows out of the overflow tube. The hose does not feel too hot to the hand. I wonder if the thermostat is working because I don't see any movement of the shutters. When I rev the engine a lot more water shoots out of the overflow tube. Perhaps it is still too full? Don't know where the fill mark is on the radiator. Book says to fill to 1 inch below the (?) don't remember the word. Of course, when I stop the engine the guage moves off center toward red and the hose is too hot to keep hold of it. Should the shutters be blocked open. Can you take out the thermoustat? I will purchase another radiator cap.
Many thanks,
Ty Stinson
Ty Stinson
'37 Cad 8519 Touring Sedan V12
CLC22330

The Tassie Devil(le)

I think that every maker states that the coolant level should be 1" below the top of the Radiator filler hole.   That is without a recovery system.

And yes, looks like your cap is not doing what it is supposed to do.

Measure the depth of the cap receiver, against the washer in the bottom of the cap.   If there is any spring compression of the washer against the seat when the cap is on, then the cap is bad.   If the washer doesn't reach, then it definitely is the wrong cap.

BUT, if everything is okay in that department, then you JUST MIGHT have a compression leak into the water jacket from a cylinder.   Leaking Head Gasket?

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

harvey b

Hi Ty, coopers in Burbank Ca have the rad caps,i got one for my 37 3 years ago and it has worked fine since,the cap is deeper than a normal cap,a regular cap will not make a seal on the inside of the water neck,my car did the same thing,it was leaking water and was going down on coolant.it was being pushed out the water neck when i was driving,couldnt see it as the hood was closed?,put a new cap on and everything was fine after that,other then a leaky water punp,but that is a different thing.The shutters need the top of the rad to be full to work properly,the thermostat is "under" waterand it needs the heat to open and close properly,i do not have the shutters on my car,they were missing when i bought the car,if the water level is below the thermostat the doors will not open and it will really overheat,the shutters can do more damage by not having enough water in the tank,i would wire them open until you get a feel for how hot the car will be running?I have no plans to install a set of shutters on my car either,am scared of them not opening,i only drive my car on hot days,dont need the extra heat for the heater?.car seems to run fine without them too.HTH Harvey B
Harvey Bowness

Stinson

Many thanks Harvey,
I will contact Coopers and buy a new cap.
Thanks to everyone for your comments.
Ty Stinson
CLC22330
Ty Stinson
'37 Cad 8519 Touring Sedan V12
CLC22330

Ty

I am very happy to report that the new Coopers radiator cap did the trick. Just ran the engine for over a half hour. Twenty minutes at idle and another 10 minutes at various rpm and there is no water leak anymore. Water in the radiator is 1 inch or so below the top of the tank. Thank you for your comments/suggestions.
Ty Stinson
CLC22330

The Tassie Devil(le)

I love it when something works like it should.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe