Closed to open conversion

[ilovemyxj]

I am doing a closed to open conversion on Sat. and I'm getting together all the parts I will need. I got a CSF radiator from radiator.com and the guy said that every brand was the same in appearance. I've read a couple descriptions of the conversion and it seems pretty straight forward except there are 2 things on the radiator that confuse me. 1. There is a connection for a hose at the bottom left side of the radiator that is the same size as the connection for the hose that goes to the overflow tank, and I'm not sure what it's for. Is it the overflow tank return line? 2. There is a fittin right under the radiator fill neck and I don't know what it's for. I've read that GDI makes a 92 and up temp sensor compatible model, but I don't have a GDI and this fitting doesn't look like it would take the temp sensor. I don't care if the temp sensor works because I already have the fan wired to work on a switch. I just don't want coolant all over my driveway and not be able to drive to work on Monday, that would suck. Please anyone who has any information to help please do so. Thank you very much!

 

[Bryan C.]

The fittings you are talking about sound like they are for the aurtomatic transmission cooler. I take it you got a manual trans right? If so, don't woory about them, they won't leak or cause you any problems.

 

[XJ88User]

Lower left is the drain, there should be a stopper in it, or you might have to see if your old one in your current radiator comes out and fits. My new radiator came with this installed.

The thing under the radiator cap depending on if it a fitting (has threads) or is a tube or pipe (no threads). If its a tube it might be the overflow outlet and you have to run that in to some form of catch or you will be spilling your anti-freeze and water mix all over the ground if you ever over heat. If it has threads I'm not sure what it would be as the transmission cooler like Bryan C. said should be on the left side, and I don't think the power steering would have a built in cooler on aftermarket radiators, not that I have seen.

Just a question why are you changing? Is the current system on the XJ not working is some way, it's just as good or better than a "normal" one. I have to admit I switched mine due to a lack of knowledge and the inability (before I found this forum) to make it work.

 

[NSW Sparky]

yea for shure what you are talking about is the tranny cooler, I just put in a new radiator last weekend.

 

[ilovemyxj]

I think I'm confused, I'm not talking about the drain because that has a plug. And yes I have a 5 spd. In the original post I was refering to the directions as if you're standing behind the new radiator looking forward. I think I should have mentioned that in the first place. Do I have to plug the tubes that come out for the transmission cooler? All of the stuff that confuses me is on the side that has the filler neck. One tube comes out of the filler neck, I'm pretty sure that's overflow tube. Next just below the filler neck there's a threaded fitting, I don't know what that is. And last there is a tube that is identical to the one that comes out of the filler neck, i don't know what that is. Oh and i'm doing this conversion because i'm sick and tired of the pressure bottle. I'd much rather have a "normal" system.

 

[5-90]

You do NOT need to plug the transmission cooler in your radiator - I usually install automatic radiators in place of manuals because they're a shade more efficient, and I've never plugged those holes.

Those pressure bottles can be had for little enough, if you do some looking. The only reason I've got a converted rig is because it was converted by the previous owner - and I'm seriously considering changing it back...

5-90

 

[XJ88User]

Okay i understand now on what side you are asking about. The threaded port on that side might be for a late model fan thermistat sensor, that sensor is a whole lot smaller tehn the original one in the 88's, it something close to 5/8ths i think. Not sure if you could just plug a late model sensor into it and have it work for the 88. Without a picture or some sort of messurement i'm only guessing on this.

I'm not sure what the tube may be though, never seen that before on any of the aftermarket stuff i have looked at.

Do these flow water out of them if you fill the radiator up, have you checked to see if the pipe and the threaded hole are connected together internal to the radiator?

 

[Bryan C.]

I think I'm confused, I'm not talking about the drain because that has a plug. And yes I have a 5 spd. In the original post I was refering to the directions as if you're standing behind the new radiator looking forward. I think I should have mentioned that in the first place. Do I have to plug the tubes that come out for the transmission cooler? All of the stuff that confuses me is on the side that has the filler neck. One tube comes out of the filler neck, I'm pretty sure that's overflow tube. Next just below the filler neck there's a threaded fitting, I don't know what that is. And last there is a tube that is identical to the one that comes out of the filler neck, i don't know what that is. Oh and i'm doing this conversion because i'm sick and tired of the pressure bottle. I'd much rather have a "normal" system.

Yes, those are for the auto trans cooler. Don't worry about then if you have a manual trans.

 

[cwlongshot]

There seems to be much confusion....GOOD PICTURES would greatly help with your question....

If in fact it is the AUTO TRANNY lines your commenting on, I agree with everyone else, dont worry about them if you have a stick. If its a electric fan temp sender hole, then you WILL NEED to plug that.

CW

 

[lawsoncl]

Many of the aftermarket radiator vendors only stock the automatic versions of the radiators. I one I received when I converted my MJ had the a/t cooler fittings. Actually It turned out to be a good thing since I converted to an auto about a year later. Also, you don't really need the vacumn valve for the heater core. Just plumb the heater hoses straight to the heater core. Those valves are crappy plastic and the later models don't even have one. Back flush the heater core while you have the hoses off too. Just keep moving the garden hose between the inlet and outlet until it runs clear.

 

[MogifiedXJ]

Those pressure bottles can be had for little enough, if you do some looking. The only reason I've got a converted rig is because it was converted by the previous owner - and I'm seriously considering changing it back...

Why in the hell would you change it back??? That's the dumbest thing I've heard in awhile, please feel free to elaborate on why you would want to commit such an etrocity. There's a reason Jeep quit using the closed system. That stupid pressure bottle develops leaks constantly. You have to buy one every year or so, in my case, because it had busted...Again. Closed system + pressure leaks = over heating.

ilovemyxj, did you reroute your heater valve or buy one from the later open system cherokee?

 

[5-90]

Why in the hell would you change it back??? That's the dumbest thing I've heard in awhile, please feel free to elaborate on why you would want to commit such an etrocity. There's a reason Jeep quit using the closed system. That stupid pressure bottle develops leaks constantly. You have to buy one every year or so, in my case, because it had busted...Again. Closed system + pressure leaks = over heating.

ilovemyxj, did you reroute your heater valve or buy one from the later open system cherokee?

To simplify things - all the rest of the rigs I've got are closed systems. Also, there's nothing intrinsically wrong with the closed system - if there were, why would the OEMs be going over to it in production, including MOPAR, Volvo, Chevrolet, and others?

The "reason" Jeep quit using the "closed" system is the same as the "reason" Jeep went OBD-I - because ChryCo bought them, and converted production in 1991. Please do review your facts - and, by the way, it's "atrocity," not "etrocity."

As far as the heater control valve, I've eliminated two of them with no ill effect - just run the hoses directly together, and you'll be fine. I've even gone so far as to replace one full set of heater hoses with copper line (using vibration stubs to couple to fixed fittings) and that was a couple years ago... I need to refine the design a little more, but I like the basic idea, and it's worth improving...

And, in case you're wondering - any pressure system is, by definition (and in normal operation) a "closed" system - elsewise, it won't hold pressure. Any pressure leak is a problem, because it takes the "closed" pressure system and makes it an "open" one. The "football" tank on the "closed" system is simple enough to replace, and I've given a source for inexpensive replacements (with cap!) and it should be changed every four or five years - for the same reason you change the pressure cap and hoses on every other system. I have noted a MINIMUM longevity of five years with the OEM pressure bottle, and I change them every four (initialling and dating the replacement, so I know when I did it) and I've found them cheap enough that I can keep a couple spares on the shelf for "just in case." The only real difference between the "open" system and the "closed" system, speaking in terms of containment, beacause the "open" system offers external containment of pressure overages, while the "closed" system is meant to have some space for pressure to develop and for the fluid to expand, while remaining contained.

Like I said, there is nothing intrinsically wrong with the closed system vice the open - properly maintained, both are quite workable. The main reason I'd like to convert back is to bring my "oddball" in line with the rest of my yard...

5-90

 

[lawsoncl]

I have noted a MINIMUM longevity of five years with the OEM pressure bottle. 5-90

I bought an oem one with a new cap. The cap never fit right and keep coming loose until I put a few wraps of electrical tape on it. Everytime it came loose, I'd boil over. It was still a piece of crap with "made-in-china" stamped in the bottom. When it came time to replace it again, I figured the radiator was probably original it needed replaced as well. I converted and it's been trouble free since.

 

[ilovemyxj]

So I finnished the swap saturday, It was hot as hell but I got it done in about 3 hours. The threaded thing was a temp sensor sending unit that i just plugged with a brass cap from my work (I work at an industrial supply store). I get the new heater control valve, in fact that's what sold me on doing the conversion. I was originally thinking about just getting an aluminum pressure bottle, but when i read one of the write ups someone did on the conversion, they said that the a/c doesn't have to work as hard, and it's true, the a/c blows alot cooler now. Since there was always a little hot water in the heater core, it always felt like the heater was on, and i hated it. So that problem is now solved since the new heater valve doesn't let any hot coolant into the heater core unless the heater is on. I also went with a 160 degree t-stat because this summer in socal is really hot, and i'm glad i did. I went to the beach yesterday, sat in traffic, and did some offraoding and i only had to turn the e-fan on twice. most of the time the temp is right at the line between 100 and 210, if it's not hot out it's a little bit cooler. I plan on switching to the 180 t-stat when fall comes so i can get the heater to work well. Oh and as far as the other tube, it was for the trans and i just left it unplugged. Thanks for all the help, and as for as the one guy who said he's going to convert back to a closed system, don't do it!!! this is the best mod i have done so far. I highly recommend this to anyone looking to make their XJ alot more reliable!

Eric

 

[nickangus]

Yes, those are for the auto trans cooler. Don't worry about then if you have a manual trans.

can i use that trans cooler set up as an oil cooler?

 

[GroversXJ]

I was also going to buy an aluminum pressure tank to replace the plastic one that keeps cracking an leaking but that cost is almost as much as buying a new open system radiator so I'm leaning that way right now.

I have done a lot of searching on it but I want to make sure that all I need is a 91+ radiator (aluminum or modine), a new unpressurized overflow trank, and the new heater control valve, right?

Thanks.

 

[MogifiedXJ]

I was also going to buy an aluminum pressure tank to replace the plastic one that keeps cracking an leaking but that cost is almost as much as buying a new open system radiator so I'm leaning that way right now.

I have done a lot of searching on it but I want to make sure that all I need is a 91+ radiator (aluminum or modine), a new unpressurized overflow trank, and the new heater control valve, right?

Thanks.

That is all you need. I would go ahead and but a HD 3 core, they should be just about $20 more...

 

[5-90]

can i use that trans cooler set up as an oil cooler?

You could, but why? You'd be miles better off using an external oil cooler - since you'd be taking heat from one engine system, and using another to dissipate it (and probably failing miserably.)

The reason the AT cooler is in the radiator is to help maintain operating temperature, and to decrease warmup time (which is not as big an issue as everyone thinks...)

5-90

 

[ilovemyxj]

So my jeep is leaking a little. It is coming from where the lower house meets the radiator. It's not bad, but what should I do? I don't want any small animals walking by and drinking the coolant. How can i stop this leak?

 

[nickangus]

So my jeep is leaking a little. It is coming from where the lower house meets the radiator. It's not bad, but what should I do? I don't want any small animals walking by and drinking the coolant. How can i stop this leak?

JB weld!!!!