Open system conversion

So I've found the DIY guide to converting from a closed to an open cooling system. However, in calling around, I've discovered that the GDI 3 core radiator has been discontinued. Is there another 3 core option or do I have to go with the 2 core?

CSF makes one

Closed system is more efficient, unless you just hate the plastic bottle. If you need a new radiator anyway, and hate the plastic bottle, then it's a good move. But, it doesn't improve anything, not worth doing just to do it.

Just order a '91 up radiator and you'll get the open system radiator.

i like the idea of making an aluminum bottle and keeping the closed system. but i am weird that way.

I forget which vehicle had it, but there are older cars with aluminum pressure bottles. Otherwise if your radiator is still good, you can get a cap that fits inline with one of the heater hoses. It's less than $10, but is plastic. Any reason in particular you want to open the system up?

Forget the company that makes them, but there is a company that makes a custom fit alum tank to replace the plastic POS.. Checok with Blue Xj over at cherokeeforum, I beleive he has one.

DPG Offroad sells the CSF 3-core and they are a sponsor. They give a discount to paid members too.

If you just want an open system, you can keep the radiator you have and get rid of the pressure bottle. All you need to do is add a filler neck in the upper radiator hose, a recovery bottle, and a few feet of hose for the recovery line.

You can upgrade the closed system by scavenging a pressure bottle from the salvage yards--Dodge and Volvo pressure bottles are good candidates for this.

You can also improve things with the stock pressure bottle by using a Stant number 10244 pressure bottle cap--lower profile, it seals better, and it has a slightly higher pressure which raises the boiling point of the coolant in your system, a win-win-win combo.

I've had nothing but issues trying to burp my closed cooling system, so I would MUCH rather convert...

I will look into CSF. Thanks for the heads up guys!

The higher pressure cap is from a Volvo, I got that advice from the techs at the Jeep dealership. It's a good way to go.

AZjeepin1 said:

I've had nothing but issues trying to burp my closed cooling system, so I would MUCH rather convert...

I will look into CSF. Thanks for the heads up guys!

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Burping can be a pain. I bought a later model thermostat housing with the sensor port, used a tap to change the threads, and installed a brass radiator drain petcock. The drain petcock I used has a small tube like extension on the end, I attach a piece of vinyl tubing to it, then pour coolant into the pressure bottle--the air rushes out of the system through the petcock--about a 30 second burp.

One thing that is important when working on a closed system is to drill two holes in the flange of the thermostat, far enough in from the outer flange edge so that the holes aren't covered by the gasket. Drill the holes 180 degrees apart, and install the thermostat with the holes at 12 and 6 o'clock. If you don't want to do the petcock in the t/housing mod then just park the XJ nose down, remove the temperature gauge sending unit from the rear of the head, then start adding coolant to the pressure bottle until all of the air in the system is expelled from the sending unit port.

I've tried the temp sensor removal trick, but to no avail... Still having issues. I'll try drilling the thermostat next I suppose.

Here is a write up on the 1992+ thermostat housing with the petcock mod: http://www.lunghd.com/Tech_Articles/Cooling/BurpAirMod.htm

Question, could you buy an open system all aluminum radiator, and just run a way heavier cap on it? (20lbs or so) Then run the mac's aluminum tank with a normal 16 lb cap? It'd help with burping and you'd end up keeping a closed system.

crazyjim said:

Question, could you buy an open system all aluminum radiator, and just run a way heavier cap on it? (20lbs or so) Then run the mac's aluminum tank with a normal 16 lb cap? It'd help with burping and you'd end up keeping a closed system.

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Doesn't make any sense to me.

If you convert to open all you need is the radiator, cap, recovery bottle, and a short length of hose. Why use a pressure bottle with that setup? I mean, if you buy an open system radiator, might as well use it, open systems are self burping.

Don't closed systems cool better?

crazyjim said:

Don't closed systems cool better?

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Have never read any definitive articles on the subject. The only real difference is in handling expanded coolant--contained in the pressure bottle or displaced to the recovery bottle and then sucked back in as the vacuum is created in the open system--no big difference in cooling/efficiency as far as I am concerned.