Refilling the closed system.

[PIKE]

Chico, You have it hooked up correctly. Since you have the tube go into the plastic bottle at the bottom and the MACs tank full to the top the plastic bottle is functioning as an expansion tank, not an overflow tank. I think you still have air in your system. MACs did not send me a cap with my tank, so I bought one for a 91 and up Cherokee 4.0 since they have the open system. The cap is designed to let fliud back into the system.

 

If you were to fill the MACs tank up only 1/2 way run a short hose from the small fitting to the ground and use a cap with the same pressure rating as the plastic OEM tank than you would have a closed system. I think thats why the MACs rep said to do it that way.

 

I try to park my truck down hill as much as I can and remove the temp. sender with the engine not running. Then fill the MACs tank until fluid starts to come out where the sender was, replace the sender and fill as much as it will hold. I run it until it warms up and shut it off. I always get one good burp. Some times I have to do it several times, and I always fill into the plastic expansion tank. Also I would not recomend more than a 50/50 antifreeze mix.

 

Make sure you have your heater turned on when you do all this too.

 

Hope this helps.

[Drahcir495]

Listen guys, I'm not crazy. Way back umpteen posts ago the discussion came up over whether to turn a closed loop system into an open loop system was better. Eagle said, fill it to the top, instead of halfway like the plastic tank and run a line from the top fitting to a second plastic tank to basically turn the closed system into an open system. Am I making sense or did I get it wrong?

EAGLE and PIKE, please chime in here.

Chico,

I am not doubting you at all :cheers:. I am just trying to figure out how this thing is going to work in my Jeep? - Rich

[Eagle]

Listen guys, I'm not crazy. Way back umpteen posts ago the discussion came up over whether to turn a closed loop system into an open loop system was better. Eagle has the same set-up as does Pike. Even BLHTAZ chimed in and said having to do it again he'd run with Eagle's set-up so not to have to mess around with the fan temp switch bung in the rad the the open system did not have because it was in the thermostat housing. Eagle used a Moroso metal tank. I bought the same one but realized it was easier to do it PIKE's way becuase the MOROSO tank required some modification to get it to mount. The MAC tank looks just like the original plastic one but is metal. Mounts the same way, hence my decision to buy it. Eagle said, fill it to the top, instead of halfway like the plastic tank and run a line from the top fitting to a second plastic tank to basically turn the closed system into an open system. Am I making sense or did I get it wrong?

EAGLE and PIKE, please chime in here.

Yes, you got it right. Take a look at the radiator cap. On the inside, is there a metal disc under the gasket that's slightly loose? There should be, and that's what allows coolant to flow back from your overflow bottle if you use one. But the overflow bottle has to be set up so the hose either goes into the bottom of the bottle, or extends down to below the fluid level if it goes in through the cap.

 

What happens is this: With the new metal tank filled completely, when the system heats up the coolant expands a little, and any air trapped in the system expands a lot. This forces some of the coolant in the system out through the radiator cap and into the overflow bottle. ALL modern vehicles with "open" systems work that way today. I haven't seen a factory non-recovery system since the 60s or early 70s.

 

If the recovery bottle has the end of the tube below the fluid level, and if the radiator cap has the little flapper disc, once you shut the engine off and it starts to cool down, the coolant (and any air) starts to contract again. That creates a slight vacuum. At this point, the vacuum pulls that little disc open and sucks coolant back from the overflow bottle like a siphon. That's the way they are designed to work. Once the system is fully "burped" it's a constant cycle -- the level of coolant in the overflow rises when hot and drops when cold, but stays in the same range.

 

When you have air trapped, such as after first refilling the radiator, it may take a few cycles. Each cycle will push out more of the entrapped air, and each time that happens the air will be replaced by pulling coolant out of the recovery bottle when it cools down. Keep an eye on the level in the recovery bottle to be sure it is always about 1/3 full when cold, and that the end of the tube from the pressure tank is covered by the fluid level.

 

Here: http://comancheclub.com/forums/viewtopi ... +burp+fill

 

Read post #4, but keep in mind that the reference to half-full was because that describes how to burp the OEM plastic bottle. For the new type (either the Moroso or this nifty, custom-made job) you eventually want the tank to be filled right to the neck, and then have additional coolant in the overflow bottle.

 

Do NOT run that tank with the overflow hose just dripping on the floor. You will lose coolant every time you run the engine.

[PIKE]

Well said Eagle, I think you and I are on the same page.

 

I checked my cap this morning and it is a Stant 16lb vented

My thermostat is a Stant 195*

 

I think every one out here will agree its hard to fill and get the air out of these systems.

 

:cheers: