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Discussion Starter · #1 ·
I switched over to a small radiator, moved the pump remote to free up space for a fuel pump and had to install a inline filler / radiator cap.

I am having trouble bleeding the system, which I expected with the way I had to route the lines. Any tips there would be appreciated but more importantly I have started the motor to try and free up some trapped air pockets and I noticed water coming out the over pressure / burp tank deal. I thought it might be a head gasket but I put a differential pressure gauge on each cylinder with 100 pounds for 30 seconds each and I cannot not get it to replicate. Ive also tried 3 different radiator caps, two 7 psi and 1 15 psi all leak the same when the motor is running for about 20 seconds.

Any thoughts? I have race in a couple weeks and need to get this sorted. I cant think of any reason other than maybe steam pockets trying to escape?

Thanks in advance, here are some pictures of my setup.

Inline filler and cap, and over pressure fitting that is pushing fluid.

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Remote pump setup

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And an over view.

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Discussion Starter · #12 ·
Swaped the radiator around. Still puking a little but far less than before. I believe its air in the system. Ive got a fill cap coming so I can put some head pressure on the fill cap to get the rest out. Fingers crossed it works. Thanks!
 

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Amazon.com: Mishimoto MMTL-Cool-PR Coolant Vacuum Purge and Refill Tool Kit, Black : Automotive

I have a tool very similar to this one. It's not exactly the same one but you get the idea. I bought it to use on my RV because it had a side radiator with a bunch on hoses. Worked pretty good. Would prolly work one yours as well if trapped air is the problem.
I bought a kit like this. Comes in handy. Can pressure test and vacuum almost any system. I used it quite a few times now.

You draw a vacuum on the coolant system, than use the vacuum to pull the coolant into the system. If you do it properly, will have little to no air in the system. Had to use it in a troublesome to bleed engine. Well worth the money.

Also found a few leaks in orings/gaskets.

 

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It's best if the filler cap is the high point of the system. It MUST at least be the high point in the return line even if the top of the radiator is a little higher. It's best if your pump is as low as possible relative to the radiator outlet. With the filler cap open, open the radiator's air bleed on top and fill the system as much as possible thru the filler cap. When it seems "full" close the cap AND the radiator vent and circulate the water for 1-2 minutes. Stop the pump. Now open the filler cap and vent again and see if there is room to put more coolant. The filler is your HIGH point on the return side and all air should collect there. Fill it, close the vents again and circulate again. Repeat until most air is out. You can also carefully open the radiator vent while circulating the water to see if any air comes out. Once coolant tries to come out of the vent, you should only have a little air left in the system which should collect at the filler cap. At some point during this process you don't want to open the radiator vent because it will either let coolant out or air in.

I don't expect you need any special tools.

You need to route a hose from the filler neck cap relief fitting to an coolant recovery tank. Once you get most of the air out of the system the coolant expands when it heats up and pushes out of that relief fitting no matter what pressure cap you use. The water heats up, expands, the cap relief opens and the water flows to the coolant recovery tank. When it cools it returns to the engine. Wit the cap is at the high point it becomes a natural air bleed for any remaining air because any air in the coolant system will be pushed out to the recovery tank and when it cools only coolant will return. This is the same way most OEM systems work and why the coolant recovery tank is checked and refilled normally, not the radiator itself except for the initial fill.
 

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Discussion Starter · #17 ·
It's best if the filler cap is the high point of the system. It MUST at least be the high point in the return line even if the top of the radiator is a little higher. It's best if your pump is as low as possible relative to the radiator outlet. With the filler cap open, open the radiator's air bleed on top and fill the system as much as possible thru the filler cap. When it seems "full" close the cap AND the radiator vent and circulate the water for 1-2 minutes. Stop the pump. Now open the filler cap and vent again and see if there is room to put more coolant. The filler is your HIGH point on the return side and all air should collect there. Fill it, close the vents again and circulate again. Repeat until most air is out. You can also carefully open the radiator vent while circulating the water to see if any air comes out. Once coolant tries to come out of the vent, you should only have a little air left in the system which should collect at the filler cap. At some point during this process you don't want to open the radiator vent because it will either let coolant out or air in.

I don't expect you need any special tools.

You need to route a hose from the filler neck cap relief fitting to an coolant recovery tank. Once you get most of the air out of the system the coolant expands when it heats up and pushes out of that relief fitting no matter what pressure cap you use. The water heats up, expands, the cap relief opens and the water flows to the coolant recovery tank. When it cools it returns to the engine. Wit the cap is at the high point it becomes a natural air bleed for any remaining air because any air in the coolant system will be pushed out to the recovery tank and when it cools only coolant will return. This is the same way most OEM systems work and why the coolant recovery tank is checked and refilled normally, not the radiator itself except for the initial fill.
Thats good info. What type of cap should I use? Closed or open for this to work? I appreciate you taking the time to write this up. It was very helpful.
 

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When first filling, I jack up the front of the car. Fill system full. With cap not installed, I rapidly drop the front end back to ground. Sometimes a big burp of air will escape.
(y)

This works. Put a two foot level across the valve cover front to back, making sure the front is higher .
 

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Thats good info. What type of cap should I use? Closed or open for this to work? I appreciate you taking the time to write this up. It was very helpful.
For the filling and normal running the car a cap with a 15psi setting should work fine. From what see in your picture the filler setup will use a common radiator cap.
 

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Also make sure those two 90s going into y are lower than cap and to have the overflow tank works as a recovery type system hose either has go into bottom of tank or needs to have a internal pipe going to about an inch from bottom
 
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