bigborebates Posted July 22, 2008 Share Posted July 22, 2008 Looking for a link to convert my 88 mj from open cooling to closed i will thank you in advance :cheers: Link to comment Share on other sites More sharing options...
Motion Offroad Posted July 22, 2008 Share Posted July 22, 2008 You mean from closed to open? ;) Look in the "DIY" section, there is a good write-up there. EDIT: Here is the link; http://comancheclub.com/forums/viewtopic.php?t=7695 Link to comment Share on other sites More sharing options...
Eagle Posted July 22, 2008 Share Posted July 22, 2008 Be very careful to read EVERYTHING regarding the sensor/sender for controlling the auxiliary fan. Otherwise, you will complete the "upgrade" (which does not add any cooling capability at all) and find that you have no way to control your electric fan. Personally, I think this swap has to be THE most over-rated and incorrectly written-up modification ever devised for the XJ/MJ vehicles. Link to comment Share on other sites More sharing options...
bigborebates Posted July 22, 2008 Author Share Posted July 22, 2008 thank you sounds like i will have to open the wallet this weekend. on the hoses which ones do i get the ones for the newer system i am assuming motion do you sell them and how much and are they in stock Link to comment Share on other sites More sharing options...
LEAD_NOT_FOLLOW Posted July 22, 2008 Share Posted July 22, 2008 As always with this specific subject I disagree with Eagle greatly. I think it's one of the better mods for the Renix era Jeeps. I can't tell you how many times I've seen the closed system fail on the trails; leaving the Jeeper to come up with a vast variety of jimmy-rigged fixes to get them back to camp. 2 litter cola bottle's only work so long on the trail before they go "pop". Ever tried to fill the system on the trail when your Jeep's hot after it over-heats? It's next to impossible to do with the closed system and get it to take any vast amount of fluid. Just this weekend mvusse ran into this problem. I can tell you that he wouldn't of had near the issues if the system was an open system. Eagle and I will probably always disagree on this topic; and that is fine. But as a person who's done the conversion on several XJ's/MJ's with great success don't let one naysayer who's never done the conversion themself talk you out of it. Link to comment Share on other sites More sharing options...
bigborebates Posted July 22, 2008 Author Share Posted July 22, 2008 Does eagle have a better option to the swap that will eleviate the issues with the closed system??? Link to comment Share on other sites More sharing options...
mvusse Posted July 22, 2008 Share Posted July 22, 2008 As always with this specific subject I disagree with Eagle greatly. I think it's one of the better mods for the Renix era Jeeps. I can't tell you how many times I've seen the closed system fail on the trails; leaving the Jeeper to come up with a vast variety of jimmy-rigged fixes to get them back to camp. 2 litter cola bottle's only work so long on the trail before they go "pop". I can tell you how many times I've seen it fail on the trails: once, in my MJ, last weekend. But then, you were there. Ever tried to fill the system on the trail when your Jeep's hot after it over-heats? It's next to impossible to do with the closed system and get it to take any vast amount of fluid. Just this weekend mvusse ran into this problem. I can tell you that he wouldn't of had near the issues if the system was an open system. Yeah, I found the only way to get it filled again was through the upper radiator hose, but I didn't get the truck cooled down enough to be able to safely remove the hose until I was back at the camp ground. In theory it is a good design; in the real world not so much. I did eventually manage to keep the temp mostly below the red zone by hopping mud puddle to water hole to mud puddle to cool the oil in the oil pan by keeping it submerged as much as possible. That's why I suddenly left the pose for the group shot for a minute and came back again :D It's been good on the freeway on the way home. As long as I'm moving I have no issues. It's all that standing still in the woods followed by a minute of high throttle followed by standing still idling that did me in. Link to comment Share on other sites More sharing options...
maddzz1 Posted July 22, 2008 Share Posted July 22, 2008 Would it be possible to keep the closed system as is but put a regular radiator in? Then the only time you would remove the cap is to get water in the system if it overheated on a trail. Would this work? Link to comment Share on other sites More sharing options...
mvusse Posted July 22, 2008 Share Posted July 22, 2008 I've been thinking about this myself, and see no reason why it would not work. But then, I never looked deep into the cooling system (yet). Link to comment Share on other sites More sharing options...
Eagle Posted July 22, 2008 Share Posted July 22, 2008 Does eagle have a better option to the swap that will eleviate the issues with the closed system??? Funny you should ask. If Eagle didn't have what he thinks is a better solution, Eagle wouldn't be foaming at the mouth over what a mistake he thinks this non-upgrade "upgrade" is. The better solution: http://store.summitracing.com/partdetai ... toview=sku I installed this on my '88 XJ in August of 2000, at the same time I replaced the original factory radiator with a new GDI 3-row unit. The Moroso tank is still going strong -- the GDI radiator crapped out last year and has been replaced. This tank uses a conventional radiator cap. It provides ALL the advantages of changing to a newer-style radiator, with none of the disadvantages. Additional benefits: The radiator cap is located at the highest point in the entire cooling system. Plus the tank, being completely filled rather than half-filled like the old plastic tanks, actually ADDS coolant capacity to the system. Link to comment Share on other sites More sharing options...
Eagle Posted July 22, 2008 Share Posted July 22, 2008 Would it be possible to keep the closed system as is but put a regular radiator in? Then the only time you would remove the cap is to get water in the system if it overheated on a trail. Would this work? Nope. Because the radiator cap will be lower in the system than the expansion tank. And you still have the issue of how to control the auxiliary fan. Using a manual switch is easy, but it doesn't allow the system to operate as designed. Link to comment Share on other sites More sharing options...
BLHTAZ Posted July 22, 2008 Share Posted July 22, 2008 There is also a very good thread here about doing the conversion an easier way... http://comancheclub.com/forums/viewtopi ... sc&start=0 It is very similar to Eagles idea, just a new twist on it ;) Trust me when I say...use one of these methods and don't do a full radiator change with changing all the hoses etc, etc... I did it and spent a lot of time and money that I did not need to spend on that conversion. I believe it was well over $400 by the time I figured it all out with sensors, fan controllers ...blah blah blah blah... :cheers: . It works well now, but it was not worth the effort or money to do it this way. I believe it is worth doing for the convenience thing though even though there is no real performance gains from it. . Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 23, 2008 Share Posted July 23, 2008 Stupid mod. I've got in this arguement at jeepforum too (yeah, awesome). There is NO POINT. If the closed system is in good shape, it will work well, better even. And it won't fail. If it's in bad shape, it won't work well, and it will fail. Hmm. So, how about the open system? Same deal. Just not as effiecent about it. Typical scenario... Jeep overheats. Owner blames cooling system design instead of 16-20years of neglect. Owner swaps neglected parts to good ones doing the conversion. The cooling system actually works. Owner's logic rules that the open system was obviously better. But I would upgrade the bottle if I had an old/crappy one. But, I JB welded the last old/crappy one I had and it ran for quite a long time after that. And to bleed a closed system, you really just need a hill. Link to comment Share on other sites More sharing options...
maddzz1 Posted July 23, 2008 Share Posted July 23, 2008 Would it be possible to keep the closed system as is but put a regular radiator in? Then the only time you would remove the cap is to get water in the system if it overheated on a trail. Would this work? Nope. Because the radiator cap will be lower in the system than the expansion tank. And you still have the issue of how to control the auxiliary fan. Using a manual switch is easy, but it doesn't allow the system to operate as designed. I never thought about the cap being lower than the exp tank. As for the aux fan, I don't have AC so I don't have one. So, the tank you used is similar to putting in a regular radiator but moving the cap to the highest point. Link to comment Share on other sites More sharing options...
offroader461 Posted July 23, 2008 Share Posted July 23, 2008 Well i have mixed opinions about the closed system...i bought my MJ in 2004 and it overheated on me..so i went and replaced ALL the closed system componets including a new cap and pressure bottle and 3 weeks later overheating....checked everything...no apparent problems? drove it around a couple days with no problems then the expansion tank blew up while the truck was idling at my G/F house...by this time i got fed up and just swapped to a open system and havent had any issues since..my electric fan on the MJ has always been on a switch also but the truck never gets over 210 unless in traffic. Now on the XJ i replaced all the components shortly after i took posession and ran into the exact same problems so i switched it over and it still has the factory thermistor in the open style radiator so my electric fan WORKS AS IT SHOULD!! comes on when it supposed to and amazingly goes off when its supposed to. i don't think its a waste of money but as everyone has stated it not neccessarily and upgrade but i feel that the pressure bottle is an inadequate piece of equipement and there should be a radiator cap in the system Link to comment Share on other sites More sharing options...
joedrives2fast Posted July 23, 2008 Share Posted July 23, 2008 My 91 seems to have an open system. I'm not sure though. Is this something they started in 91 or did the previous owner do it. I have an over flow tank. My temp sensor is on the thermostat housing. and I have the heater by pass valve. This is my first MJ. My old man has a 96 XJ but I never really paid that much attention to the details. I keep finding weird stuff on my MJ that doesn't quite add up. Link to comment Share on other sites More sharing options...
BLHTAZ Posted July 23, 2008 Share Posted July 23, 2008 Yes, your '91 was built with the open system. :cheers: Link to comment Share on other sites More sharing options...
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