Rob Jordan

So, I'm pulling the motor on the 89 XJ that I bought 2 days ago. One of the things I've thought about doing is switching some things around. Has anyone ever thought of or actual switched places, the battery for the over flow tank? It just seems like it would make more sense, having that tank nearer to the radiator. I'll be removing the air conditioning system so that would free up some space. Since what's ''installed'' now is a small plastic container (looks like it was a small container of coolant) instead of any proper overflow tank anyway, it seems like an opportunity. I'll also be able to eliminate that weird upper radiator hose that snakes around the compressor (and replace it with a shorter one). This is my first Cherokee so I can't speak from experience, but it looks problematic, seems that it might make some of the motor difficult to work on, and looks like hell. Thoughts?

Background info: Motor is being pulled to replace all the gaskets, hoses, water pump, rear main seal, whatever else looks old and tired and clean it up. The Jeep has been sitting for a few years without being moved or started. It runs smooth as silk besides the cracked header. Other suggestions of any practical improvements that I could do at this time are appreciated.

DFlintstone

No. There are more reasons not to try to switch the battery and the expansion bottle on an 87-90 Renix Jeep to list. No doubt, forget that. (if you switched to an "open" system, it would just be impractical, not impossible) Just leave the bottle 1/2 full so air in there can compress. (these closed systems are different, no overflow for example). If you fill it it might "pop" the bottle, because water doesn't compress. Napa bottles have a lifetime warranty BTW. (I needed to get the guy to look at his screen closer to see that once)

Rob Jordan

Thanks for the reply DFlinstone. It appears that my system was at one time or another converted to an open system (or at least they changed out the radiator). My radiator has a cap on the right. The previous owner's son (his dad passed away) told me that he recalled the Jeep having a cooling issue of some sort. He stated that he thought it was the water pump (which I doubt on face value, but it's on the list of parts to be replaced anyway). Does this change anything?

DFlintstone

The original system has at least two potential problems. One is people don't get it you need to leave the bottle 1/2 empty or it might burst, with no air to compress. A second it "burping" it, just getting it full in the first may, or may not be easy. With the air hole in the correct thermostat up at 12;00, parked at right angle with time it fills fine.
Anyway. The conventional system with a rad cap, the recovery bottle can be a ways away but is best near the same height. It's cap has a one way check valve and seals in two places allowing vacuum from the system as it cools to draw coolant back from the recovery tank to the Rad, via the tube to the neck between the two seals. I suppose a guy could get creative, put ti where you like. Do keep in mind battery acid will eat about anything given time. Any issues there at the corner of the firewall and fender woin't be any fun, but heck, it shouldn't leak!
I

PatHenry

Also, if you're new to Jeeps, XJ's, etc, you will find a wealth of information for your Renix era Jeep at Cruiser's site www.cruiser54.com. He's a regular contributor on this forum as well. Make sure you post the year or "Renix" in your post titles and he and other Renix-era experts see them.

Rob Jordan

My XJ was switched over to an open system some time ago. The previous owner put a recovery bottle from a Nisan into the engine bay with a zip tie. I'm eliminating the entire air conditioning system and am putting in a pulley on a bracket to replace the compressor. For the moment I'll be eliminating the heater core as well. The vehicle had been sitting for several years and the water that was inside the motor was very rusty looking. I'm afraid that if it doesn't leak right off the bat that it soon will. Regarding the idea of switching places (battery/overflow tank) I've abandoned the idea. Thanks for the link PatHenry!

DFlintstone

Likely a good idea to forgo the hassle of fabbing a new battery mount. Your project sounds like fun, maybe post up some pics when you "get there". Besides Cruiser's page there is a mess of random Renix stuff in the link in my signature, including this > Thanks to 88Dutchman>>
AC Compressor Bypass/W Idler Pulley For 87-90 Renix