Hot Rods SBC puking water .....resolved

This is a fresh build and after it warms up and while driving down the road you begin tasting antifreeze Here's a picture of the "mess". It doesn't over heat....it actually doesn't really warm up...I wondered if the gauge was broke but when I "shoot" it with a laser temp device it shows about 140 degrees at the gauge probe...around 180-185 on the front of the heads. 180 degree thermostat. Once I left the cap off and cranked it and it puked a lot of coolant out...I've used both a 6 # and a 16 # cap with the same leaky results .
I'd like to be able to drive more than a mile...although it won't be long here in Iowa that a mile in an open car might be enough I usually just throw parts at it but maybe it's something simple?

 

Maybe the water pump you have spins in the wrong direction ( reverse rotation)? I can’t think of anything else that would cause it to puke without overheating.

 

do you know where it's coming out?

I like to test drive a bit with only water in the cooling system until I'm sure it's working right, before adding anti freeze....

 

Shouldn't your cap be higher than than the tank?

 

Run a higher pressure "recovery cap" with the overflow bottle.
With a non-recovery cap the radiator will consistently lose 3/4" to 1" of water level due to heat expansion [ you can top it up forever but the level drops when it cools down]

Recovery caps are labelled [but yours doesn't show that]

Puking coolant with the cap off is usually an air lock

Yep! it has an air lock caused by the radiator top tank being higher than the outlet and cap.

 

Probably should puke with that cap set up

 

Those copper lines look just “stuck in the holes” on top of the recovery bottle.

I think they would need to be sealed to keep the pressurized coolant from being pushed out around the tubes.

 

Catch cans and expansion tanks are different
Kinda looks like a system that needs an expansion tank but has a catch can

 

My best guess is, a trapped air pocket (a big one) expanding, pushing coolant, and overfilling the spit can.

 

I expect the radiator upper tank never gets full, since the filler neck is below it. So, there's the expansion tank.

 

And the catch can can’t hold pressure

 

Can’t get the air out with that set up
Could use a coolant vacuum to pump out the air, then draw in the coolant.
The catch can set up like that probably aint gonna work. Catch cans usually plumb just under the cap. But under a cap mounted above the tank. To use the can, it needs plumbed to the top of the tank

 

Jack the ass end up in the air about 3 feet lol

 

That’s how I did rear engine cars until I finally bought one of those vacuum thingys

 

I've had numerous, and I mean numerous, sbc powered cars that puke down to where they wanna be, and there no sense in adding more, because it's just gonna kick it out. But this one looks to me to be an air pocket issue. Raise the rear so that the fill cap is higher than the top of the tank, if that's possible. If not, you might have to redesign your setup.

 

It's a "dynamic expansion tank" so the pump can circulate aerated water throughout the system

It doesn't need to.
As long as the tube goes to the bottom of the bottle , it can syphon back when it cools down.

It needs the correct radiator cap AND no air in the system

 

Thanks for all of the responses....and to things I hadn't thought of.

It leaks around the cap. The filler neck is a copy (I assume) of a early Corvette Piece, I bought it at speedway https://www.speedwaymotors.com/Inline-Die-Cast-Filler-Neck-1-5-Inch-Hose,9010.html after the radiator shop wouldn't put a fill on the upper tank....
after reading some of the remarks I looked at the listing and it almost sounds like the 1/8 inch pipe fitting should be for a bleeder and not for a catch can.

For what it's worth, the line that comes off of the filler neck goes to the bottom of the catch can, and the second pipe is used as an overflow since it's only an inch or so into the catch can.

Did early Corvettes (like yours @squirrel ) have the fill neck higher than the radiator?

I suppose I could pull the radiator and have them raise the upper neck?

I didn't know there were different radiator caps for coolant recovery And I thought by the time I got this age I would know it all

 

Those in the hose filler necks are designed to be the high point of the cooling system.
Normally they go in a system that has a cross flow that sits below the level of the engine buy will work with any system that the hose is high enough in. With that radiator that shouldn't be an issue as level in the filler neck is right were you want the level in the expansion tank. It is also above any water jacket in the engine and there is no heater core that might sit higher.

Now: what was the donor car/truck for the engine ?
Short pump and V belts but is the pump for a V belt engine or the year model of the block? Pump has to match the belt system on the engine not the original year model of the engine and if you bought a short pump for an 80 something you most likely got a reverse rotation pump.

Air bleeder hole drilled in thermostat body? That helps get air trapped under the thermostat out.

Is that by chance one of those year model of engines that wants to have the heater hose hooked up even if it is just a hose from the back of the intake to the water pump to circulate coolant though the passenger side head? Someone better versed in small blocks than me might have to fill in the blanks on that but I am thinking engines around 78/79 are that way.

 

Thanks for all the replies...I appreciate the time you all have taken to help me

@Mr48chev The block is an 87 or 88 and I wondered about the reverse rotation question myself, the engine had been in a Model A before it was set in the T. I guess I could always swap in a known (painted orange and rusty) old short pump.
The prior owner bought the kit for his grandkids and donated the engine. I had assumed that it was all "old style stuff", I'd ask the prior owner but he has so many cars I doubt that he would remember. There is no bleeder in the thermostat housing but I did drill a 1/8th or so hole in the thermostat, I had to have a fancy chrome unit so I could get the hoses to line up and clear the air cleaner. I hate those adjustable pieces of crap that I have a hard time sealing

 

This is a 1960 Corvette radiator....in 61 they went to a cross flow design, with a separate surge tank, which had the pressure cap on it.



This is what my 62 has, the cap is on the surge tank, which is the highest point, and there's a tube from the top of the radiator to the surge tank, so air can escape.

 

Headgasket leak ?

 

Get another radiator shop [soldering on a separate filler neck is really easy and common for them]
My C3 Corvette had an inline filler neck like yours , but it was at the highest point in the whole system

Here is a standard radiator cap


Here is a recovery cap [it has a second seal "blue"

The centre is a vacuum valve that allows coolant to syphon back [when cold]


Most recovery systems are high pressure [20 psi +] so make sure your heater "if fitted" can handle the pressure

Even if you raise you inline filler neck, you still need to address the issue of an air-lock in the top tank
Leave the upper neck as-is ,and just add another 90° filler neck where that other soldered patch was.

 

That looks to me like the way to go...

 

Can you extend the fitting that takes the cap higher (cut/ insert/ weld), as close to the normal height as possible?

 

Make sure the thermostat is in right side up and drill an 1/8" hole in the poppet. The hole lets trapped air out as you fill. At least it does when the fill is in the tank.

Gary

 

There is NO airlock in the top of the tank, That is "room for expansion" the same as you always leave in a top tank radiator. If you look at his inlet hose the top of the neck is where and maybe above where you would fill the tank to if you were filling it from the top. That should not be the issue. There is nothing in that cooling system above the top of the radiator hose where it goes into the radiator.
The issue is either an air lock in the engine or a wrong for the belts rotaton water pump.
As far as the pump, my first experience with one of those was on Third gen Camaro that somewhere along the line got a mid 60's 327 stuck in it complete with V belts. One of those rather abused cars that had changed hands who knows how many times. It came to the shop I was working in because it would overheat on the road. Then it actually cooled down when you slowed down. I left that job about that time for one that involved more front end work and a couple of weeks later an article came out in Hot rod or Car craft that told about pumps with the wrong rotation for the belts being put on an engine and it in turn overheating. I've seen it both ways since. 80 something engine stuck in a 60's or 70's ride and the front hardware off the old engine put on it complete with V belts. The other one was a mid 80's engine put in a mid 70's truck and someone put a pump for the year of the truck rather than the serpertine belts on it.

I've had the air lock under the thermostat happen on a couple of my own rigs and usually drill a hole in the hull part of the thermostat when I put one in. My OT ride has a bleeder screw on the thermostat housing to bleed the air out. Don't bleed it it does exactly what the OP said was happening.

 

It looks to me like the leak is coming from the cap itself. That shouldn’t be happing even it it’s boiling over. The excess should be going to the catch/expansion tank. That’s how the caps work hence the two sealing surfaces.

Either your cap has a duff seal (the big one) or the filler neck where it fits is bad, or the overflow pipe/can is blocked.

 

That is a pretty car.

 

There is an airlock in the top half of the tank , it is not an expansion area but a incorrectly modified radiator.
For that to be "room for expansion" the air needs somewhere to exit
Otherwise it will compress to the same pressure as the Radiator cap [I have never known of air to compress to zero volume]
And then water will start puking out when the water volume expands more [resulting in more air in the system when it cools]

On his radiator there is too much volume above the radiator outlet. The worst thing is this air can circulate into high spots in the engine


All radiator manufacturers have the radiator cap at the highest point of the tank or a hosetail to bleed air to a remote tank with a radiator cap [that is at the highest point]
Even GM put an air bleed tube on the corvette radiator that @squirrel posted above [#20] to prevent a slight airlock

@vtx1800 could add a hosetail to his radiator and use a remote pressure tank but if he's going to pull the radiator to solder this , he might as well do it properly and add a 90° filler neck.

Does he have the wrong water pump??? Who knows ,until he pulls it to find out.
But he say that he doesn't have an overheating problem, just a puking problem.

Either way with the water pump he will still need to address the radiator airlock issue [the radiator cap needs to bleed air out , not water]

 

I built a customer's car years ago with a flat head with the same type of radiator cap in line on the hose. If you had the cap off while running, it would definitely push water out, but with the cap on, it was fine.try another cap