Coolant Tank

[Ken Roberts]

Here are the ideal expansion tank caps to use if running a LS3, LS7 or LS9 engine. GM used a 18.5psi rad cap on the C6 Corvettes up until about 2010. They then jumped to a 20psi cap in the 2011 model year.

The aluminum expansion tanks by Canton and Moroso use a Standard SAE "A" size of filler neck. The best types of caps to use that take less effort to remove (not as frustrating) are those with the levers. These are the best choice as long as you have a bit of room above the cap with the lever "lifted". A side benefit is there is less strain on the expansion tank filler neck to apply or remove it.

The Stant part number for the "lever" type of 18psi cap is #10334

More Information for STANT 10334

The Stant part number for the "non lever" 18psi cap is #10234

More Information for STANT 10234

The Stant part number for the "lever" type at 20psi is #10335

More Information for STANT 10335

The Stant part number for the "non lever" at 20psi cap is #10235

More Information for STANT 10235

The Stant Racing version of the 20psi cap is #10381 (3 times the price)

More Information for STANT 10381

 

[Dan Carter]

Thanks Ken

One last bother (I hope). I took what you said and combined with the WIKI, drew the attached diagram. Do you mind giving it the once over? Did I capture it correctly? :stunned:

I work better with pictures...go figure. :thumbsup:

 

[Ken Roberts]

You nailed it Dan. Nice diagram. Just remember that when the heater flow control valve is installed it should be to the left side of the 3/4" heater hose tee.

 

[Dan Carter]

Roger that. Just haven't gotten that far yet.

Thanks for the second look.

 

[Tony Eupizi]

Is the vapor vent from the radiator necessary? Most production cars don't have them.

 

[Ken Roberts]

Is the vapor vent from the radiator necessary? Most production cars don't have them.

The C6 Corvettes do. I guess when the radiator is sitting lower in the car it becomes more important.

 

[Scott Davis]

Thanks Ken

One last bother (I hope). I took what you said and combined with the WIKI, drew the attached diagram. Do you mind giving it the once over? Did I capture it correctly? :stunned:

I work better with pictures...go figure. :thumbsup:

The only issue I see relates to the high/low comment you were confused about. I too was confused at first because I read it as upper and lower (location) instead of High pressure side vs low pressure side. I had to read it twice then I got it.

Anyway...you still have it on the high pressure side. Maybe that's because you only have one petcock and that's where it is. Might have missed that.

Is the vapor vent from the radiator necessary? Most production cars don't have them.

I'd guess that higher operating temperature make them more important as well since you could generate/carry steam outside of the heads as well. Most production cars won't be ran at such high temps.

 

[Dan Carter]

Scott

High pressure versus high location......makes sense now...but

The radiator I have does have a second petcock which is in the opposite corner (on the return to engine line) lowest physical location (drain petcock?). In review of the build manual picture below, it looks like the radiator vent line is the same as the upper petcock on this SLC radiator (is RED high pressure, or hot fluid?).

I assume the intent of the vent lines is to help eliminate trapped air/steam. Not sure but I thought the engine steam vent is considered part of the high pressure side of the plumbing like the high side of the radiator, but to your point maybe not.

In the grand scheme of things when/where does the flow transition from high pressure to low pressure?

How would you change this up?

Thanks

 

[Scott Davis]

The high pressure side correlates with the red side and low pressure side with the blue side and doesn't necessarily have to do with the temperature in this cause but rather (or mostly) the proximity to the pump outlet. The vent line are also "low" pressure. The closer to the pressure created by the pump the higher the likelihood that fluid will want to escape to low pressure. So in theory when the fluid enters the radiator tank on the hot side it may went to be pulled into the vent line instead of traveling through the radiator. There is less of a chance of this on the cold side tank. In practice I'm not sure how often that happens. In the SLC the coolant has a long path to travel before entering the radiator and could lessen the affect. If I had petcocks on top left vs bottom right, I probably wouldn't worry about it, I just happen to have petckock top left and top right.