cooling system bleed lines ?

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bob peckham

• Dec 9, 2008

• #1

Hi, planning on running a line from the left rad tank to the fill tank on the firewall and a set of lines off the back of the intake connected and then going into the fill tank, Im thinking #6 an line/hose would be enough. the car is a rcr with a 418 any different thoughts thanks Bob

 

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Jac Mac

• Dec 9, 2008

• #2

Too Big-thats 3/8" bore, you only want to bleed the air, not water- remember what goes thru the bleed lines isnt going thru the radiator and water/coolant will take the easy way every time which in this case would be the bleed lines, bleeds from rear of manifold should only be reqd where motor is level or slightly nose down for most applications, but are a must in Hi HP applications where its inevitable that a bit of compression leakage etc will occur, most important is the bleed from the highest point on the manifold directly behind the t/stat to the header tank.

 

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bob peckham

• Dec 9, 2008

• #3

Thanks for the quick reply what you said does make sense thanks again Bob

 

Howard Jones

Supporter

• Dec 9, 2008

• #4

I used AN4 lines. Same setup as yours with the third point at the water temp bung on top of the intake. I have all three intake points "T" together and then onto the header tank. Works very well.

 

Last edited: Dec 9, 2008

Rob

Lifetime Supporter

• Dec 9, 2008

• #5

Bob,
I'm with Jac Mac on this one.... too big and you will run coolant volume through it. And I'm always surprised what kind of volume can flow through a 3/8" line....
I ran 1/4" OD hard line. Even this flows quite a bit, but didn't want to take any chances of crap plugging in up in the future.

 

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Jac Mac

• Dec 9, 2008

• #6

Just as an afterthought here for the disbelievers- we can cool a 600+HP jetsprint/marathon race boat with one single 0.500" bore line from the unit with either direct or heat exchanger systems, so in the GT40 example it stands to reason that if you start using 3/8" or larger bore lines for your bleed system that coolant flow thru the radiator is going to be seriously reduced.

 

Ian Anderson

Lifetime Supporter

• Dec 10, 2008

• #7

What about using a hard brake line pipe to run the bleed from the rad back to the header tank? ( I believe 3/16 inch)

It will move the air but as you say restrict water flow.

Something I am planning to do over the "closed" season

Ian

 

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Chris Simpson

• Dec 10, 2008

• #8

Hi Ian

That is just what RF do - use copper brake line.

Chris

 

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J. Salmon

• Dec 10, 2008

• #9

I have asked many folks about bleed lines for the LS7, and gotten a lot of blank stares. Anybody want to help me find ports or a place I should use a bleed line?

 

Rob

Lifetime Supporter

• Dec 10, 2008

• #10

Bob,
Forgot to mention, the line that goes to my reservoir even has a restrictor in it with a 1/8" hole drilled in it. I found that the flow going to the reservoir was quite a bit more than I wanted. Again, the goal is to carry air, not a volume of coolant.