New overheating problem 87, 4.0, XJ

[1990JEEPXJ]

the first post ive seen that actually notes the benefits of a fully functional, maintained closed system. thanks for the info mike. i just with they made quality pressure bottles these days. like many others, i go through them like theyre going out of style. about once a year i need a new one due to cracks, which lead to leaks, and eventually pop.

 

[winterbeater]

I was looking at the pressure bottle on my '99 Crown Vic. Never any problems with it. It has a hose from the bottom of it (2-2.5" hose?) that "T's" into the lower rad hose and a hose near the upper side from the upper radiator (1 3/4 or so?). Would that work for an XJ closed system? JY must have millions of them. No cap issues, etc.

 

[Ecomike]

I was looking at the pressure bottle on my '99 Crown Vic. Never any problems with it. It has a hose from the bottom of it (2-2.5" hose?) that "T's" into the lower rad hose and a hose near the upper side from the upper radiator (1 3/4 or so?). Would that work for an XJ closed system? JY must have millions of them. No cap issues, etc.

I think the Ford Taurus has the same style plumbing. Bottle connected to the upper and lower hoses. Isn't the Renix bottle connected to both sides of the water pump? A difference I had not previously given any thought to! Is that really any different? At first thought I would say no.

I hear the Volvo bottle is a good substitute also.

I have high hopes that the bottle cracking is mostly due to the hood being too close and crushing the bottle, so I have not quite given up on the cheap renix bottle itself. The Volvo and Stant aftermarket Volvo cap work great on the cheap bottle, and seems to have solved the hood contact (cap is half the height of the curent crown cap that comes with the crown bottles) and loose cap problem. People that have lowered the bottle shelf so it does not hit the hood, and who put a worm gear clamp on the bottle cap have reported much longer service with out bottle and cap failures, including 8Mud and 5-90.

 

[Ecomike]

Been about 6 weeks now (87 Renix update). Yesterday we got back up to about 95 F ambient, >90% humidity, and I got stuck in mid day traffic for an extra hour of crawling traffic on 33 mile trip. AC on Max, no problems. Renix bottle with Volvo cap is holding up nicely. Coolant temps unchanged, and the 16 lb cap on the inline filler neck has never opened or vented as I theorized, renix coolant bottle is still 1/2 full, unchanged, so my closed/open Renix mutant hybrid cooling system is working perfectly. Holding 180-200 F at the thermostat housing for 60 F to 95 F ambient days. Note my thermostat is 180 F.

Summary of relevant changes I made. Installed a new CSF 3 row Brass/copper radiator, new 97 parallel flow AC condensor on the R-12 converted to R-134a AC, new ZJ (grand cherokee standard FC) fan clutch, new standard water pump, and new POS plastic Renix Coolant bottle with a Stant brand Volvo bottle cap on the Renix bottle.

I have also determined that my renix is indeed running leaner, and thus hotter, which is why I had to clean up and make improvements to the cooling system. In spite of the 1 hour traffic jam and poor mileage I still got a 15% higher mileage on the last tank of gas than I got anytime in the last 4 years. I have had a bout 20% increase in mileage since my renix started running hotter.

Also note worthy is that just before it started running hotter I replaced the harmonic balancer. The jeep sat up for 4 weeks during that time. When I started it back up it had a terrible, very load valve train noise, much worse than valve-tappet-lifter noise I had gotten use to the last 40,000 miles and 4 years. So I did a trick that 5-90 taught me that had worked to some extent the last 9 months, which was to run the RPM in park up to 3500 and hold it for a minute to free up the stuck lifters. Well ever since I did that the last time, just after replacing the HB, the 4 year old lifter noise (always worse in cold weather, and first days start up) has been gone completely, and the engine runs hotter, and leaner, and gets better mileage ever since that day.

 

[Ecomike]

Problem still solved, no overheating since my last post. This has been my DD since the last post.

For those having any cooling problems with Renix, I am still using the Volvo cap and Modified Renix bottle, and other modes I discussed here and in my other Renix cooling problems threads here last year. So far the mods all working perfectly, in 95 F Texas humid heat.

http://www.naxja.org/forum/showthread.php?p=244999945#post244999945

http://www.naxja.org/forum/showthread.php?p=244999942#post244999942

 

[Andy Steiner]

The Renix system has to get up to about 265 F for the system to reach anything close to 16 psi, as the air in the bottle is compressible. In fact the Renix system does not vent at all, not even air with a properly working cap, contrary to what I and others have said in the past, it is a true closed system.

Mikelopedia says that a Renix system wants a 13lb radiator cap. Didn't you say you were using a 20lb cap?

 

[Ecomike]

Mikelopedia says that a Renix system wants a 13lb radiator cap. Didn't you say you were using a 20lb cap?

First off, I have a 2 cap system now, maybe the only one in the world?

The Renix OEM bottle cap is a 16 lb cap, and I have an after market Volvo bottle cap on my Renix *which is about 1/2 of the height of the currently available aftermarket Renix cap, and it actually holds and seals). Then I have a 16 lb radiator neck style cap on the inline hose filler neck I added, which has never opened to vent since I installed it.

The filler aftermarket upper hose neck and cap is for degassing the radiator, and for filling the radiator, easily and quickly. The Bottle is that I can keep the closed system, and see the coolant level.

 

[Ecomike]

Dec 11, 2010 update. Still no problems, no leaks, no overheating, no coolant loss. Fix has stayed fixed now for a good 16 months.

 

[Ecomike]

I discovered recently, while doing an AW4 swap, that the donut flange exhaust at the manifold to exh-pipe, was loose, nuts were loose enough that it had to be blowing hot exhaust on the block, which was another part of my 2009 summer over heating problems.

Be interesting to see how much cooler it runs this summer with the leak gone.