I found this picture on google. It's a Renix era Cherokee with an added radiator cap. I thought it was interesting, so I saved it. The rest of the cooling system looks to be stock Renix closed system. Everybody knows that the closed system on the older Jeeps is a pita (myself included) to get all of the air out of. I'm wondering if this would make things easier? I've never seen this done on any Cherokee before.

 

I would think you would want a resivior on the end of that overflow line but maybe there is one that I cant see. It might help with getting the air out but I think you would need the res to keep from sucking air back in.

 

looks smexy except for that intake you should really do something with that but yeah it looks good

 

Looks like they used the stock pressure tank as an overflow, with a hose going out the top in case it boils over. From what I see, they upgraded to the open system, but added that radiator cap piece instead of buying a new radiator

 

Do you think it functions the same? I would love to do this to mine, if it serves the same function as the open cooling system. I wonder what all is involved.

 

buy this cut the hose put it in do some plumbing and your donehttp://www.summitracing.com/search/?...20filler&dds=1

 

Should work exactly the same. As long as your radiator is in good shape, this would be a great way to change over. Just run the hose from the radiator cap to the bottom hole on the stock tank, then a short vent hose from the top of the tank. Found this from a few months ago where it was already discussed.

https://www.cherokeeforum.com/f2/ren...d-shift-63044/

 

As cheap as it is to convert over to an open system I don't see why people are still using closed systems. My old 90 had nothing but issues with the closed system, I think it cost around $80 to swap over and that included the coolant.

 

I would think the rad cap needs to be the highest point in the system, in order to properly bleed air out of the system. Kinda hard to tell for sure from the pic, but left of the rad cap looks like the highest point. When doing the conversion, the small coolant pressure relief hose at the base of the rad cap absolutely must enter at the base of the overflow bottle and the overflow bottle must always have some coolant in it, even when the motor is cold.

http://www.jegs.com/i/JEGS-Performan...ductId=1206366

 

that is pretty much lhe highest part of the system should work ,if you radiators shot its about 150 to do it properly

 

when i bought my 88, the po had already added the prestone flush "t" into upper hose, and replaced the oem pressure/overflow bottle w/ a diamond-plate aluminum bottle w/ a 16 lb rad cap. this makes it an "open" system. should the system then burp itself? if so, where should i route the overflow hose that's comes from under the cap? i'm also trying to trace down overheating issue (elec. fan not coming on.) don't worry, toggle switch in progress.

 

I think u still have a closed system. I would think the over flow bottle needs to be clear.....so u can tell if the system (rad cap) is functioning correctly. U should see coolant level rise/fall in the bottle as the engine heats/cools. Rad cap needs to be at the highest point......that's where air will accumulate and be pushed out to the overflow bottle. Again, the small tube from below the rad cap must enter the bottom of the overflow bottle.

In an open system the bottle is not pressurized, like it is in a closed system.

 

It looks as if that is the case with the Jeep pictured above. IT has the line going from below the radiator cap to the bottom of the bottle. Are you thinking that the coolant tank should be mounted lower than the stock location so it is lower than the radiator cap?

 

In the pic, the rad cap looks like it would be higher if it were located beside the compressor vs beside the pulley. In an open system, the bottle can be mounted just about anywhere as long as the small tube from below the rad cap is attached to the bottle at the bottom.

 

Great, that's what I need to know. I think I'm ready to pull the trigger and give it a whirl. So, I guess the only steps are to connect the two hoses that originally go to the pressure bottle together and put the radiator T fitting in the top radiator hose, run the hose from below the radiator cap to the bottom of the pressure bottle and presto!


Will my heater core be affected at all by connecting the two pressure bottle lines together? (just want to be sure and cover all bases)


Thanks to everybody for the help btw.