brownacc

60 Corvette 283/230 engine complete rebuild 5 years ago with only a few thousand miles on it. Bore 60 over built like stock with new radiator and water pump . Every since engine was installed it has pushed out some water after a drive and parked , not every time but often . Not running a thermostat , the housing is there but I cut out the center " always have ? " . Engine run normal temps and does not over heat " check with a temp gun at cast thermostat housing , radiator and hose . Temp at housing runs about 200 on a hot day and will build up after cutting engine off about 15-20 degrees .
Will push out a small puddle and stop .
Today while warming up I checked the air in tires and notice it pushing out water and temp gauge flukuating , top hose had no pressure . I took cap off and added half a gallon or a little more . Drove it for about an hour with no heating but again after parking it some water pushed out .

Running a 7 pound cap , put a 13 pound cap on today to see if there's any change but not ran the car yet .

What do you guys think ?

wraplock

If your temps are good and your radiator cap is working properly that is opening at the pressure designated on the cap then I would say you are overfilling your radiator. As the coolant reaches operating temps it expands and increases pressure in your system. When you shut off your engine the coolant temps rise even higher due to heat soak. The cap opens and allows the excess pressure and coolant to escape. Do not overfill your radiator, You must leave a couple inches for expansion. You could always add a coolant recovery tank to your system. When the cap opens as pressure builds your coolant will go to the recovery tank, as the systems cools down it will draw coolant back into the system as needed.

Don

ohiovet

Sounds like the cars cooling system just "puked" out the excess water.
Should not be a problem.

ejboyd5

Overfilling. Let the system vent the excess to find its own level and leave it at that.

GTOguy

Overfilled, but the main issue is the 7 pound cap. You want at least a 12-15psi cap.

wraplock

Running a higher pressure cap may have it's advantages in light of the fuel additives and higher operating temps we are seeing today, however your system was engineered to operate with 7 lbs of pressure. Increasing the pressure of the cap is ok if you do not have an aged heater core hiding inside your heater box. I increased the radiator cap pressure in my 1956 Belair when I installed a new 350 and a new aluminum radiator, the very next day my original heater core sprung a leak. Just something for you to think about....

GTOguy

wraplock, I had no idea that 7psi was the standard PSI for a '60. What you said is true about excess psi. But if the system is up to snuff, the higher PSI is better for modern driving conditions (traffic and speeds).

wraplock

Agreed

Bill Pilon

My 60 Vette came with a 7# cap and still has one. Runs at 160 degrees all day long and no puking after shutdown. Bill

Pilot Dan

You don't say what type of radiator you are running but if it is an original copper design added to trying to cool a + .60 bored engine which is producing more heat than the stock design, it does not surprise me you are running on the hot side. The water (hope you have it mixed with coolant as well) as others have said will puke out till it finds it's sweet spot, but the hotter you run the lower the coolant level will ultimately be after several heating cooling cycles. On my 59 I run a Dewitts aluminum radiator which is 30% more effective than the old standard copper, and the car NEVER goes over 180* . Pilot Dan

Jud Chapin

[QUOTEl

Running a 7 pound cap , put a 13 pound cap on today to see if there's any change but not ran the car yet .

What do you guys think ?[/QUOTE]

I suggest installing the proper cap the car calls for. I think the 13 is too low also. I believe a 15-17 is correct, but not sure. That may be your only problem.

tuxnharley

Each psi rating on a pressure cap increases the boiling point of a 50/50 water antifreeze coolant mix by about 3* F. Thus, even your stock 7 psi cap raises the boiling point to about 240*, from its starting point of about 220* That's all you need. If you need your car to be able to reach greater than 240* there is something else seriously wrong.

https://durathermfluids.com/pdf/tech...ling-point.pdf

Also, increasing the working pressure in a closed system is not necessarily a good thing. Yes, it will increase the boiling point. However, it may also decrease the pump flow rate. The higher the pressure (head) that a pump has to push against, the lower it's flow rate will be. Doubling the working pressure form 7 to 15 psi seems like a large increase to me.

I'd want to know what the design parameters of the pump and system were before I'd make that big of a change. Or, maybe make sure the system is functioning properly as designed, and assume that the GM engineers involved knew what they were doing.

Either leave some room for expansion in your radiator, or add an overflow tank.

Ryan427

Going from a 7 psi cap to a 13 fixed most of the problems on my buddy's '56, but he's got it in the shop adding an overflow tank right now.

Ryan427

There it is, overflow tank freshly installed.

Faslane

Let it puke, it will find its level.

JohnZ

And put a thermostat in it.

stratplus

In my 60-327 I run a 7lb radiator cap, a 180 degree thermostat and a Dewitt's direct fit radiator for a 60.

After filling the radiator the car will puke all day until it finds "its spot" and then it stops puking. It will puke out about a quart and then it is happy.