• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Renix radiator cap hose mod?

I did not use an overflow bottle, just a hose off the nipple to a low spot near the front bumper. I still have the Renix bottle in the stock position.

I decided to see if it ever overflowed before worrying about an overflow bottle. Turned out my theory was correct, that Renix closed system does not need an overflow bottle at all with the hose filler neck mode.
 
So.. the only way to know if it has ever "over flowed" is by keeping an eye on the coolant level? Is there any reason to add the filler neck other than easy of filling/bleeding? Or.. do you think that with the filler neck pressure bottle life might be extended?
 
The stock renix plastic bottle cap is about 15-16 lbs, and yes it it is designed to relieve excess pressure. One could use an 18 lb cap on the filler neck to insure it never opens, and that the bottle cap always opens first.

The only reason for the inline filler neck is to get air out and make filling much faster and easier. Renix plumbing is notorious for trapping air in half the radiator and nearly never completely getting purged of air in the radiator because of the poor plumbing layout. In line filler neck solve that problem.
 
Heres the part for the mod http://www.summitracing.com/parts/MOR-63745/
Don't get a cheaper one or you may have probs with the cap mounting surface wearing down and the cap not sealing right. I forgot what cap you get for it though. Here some pics of what my set up looks like.

nana008.jpg

nana009.jpg


I eliminated the heater control valve and all the BS plumibing in there and my heater works killer now, did'nt even heat up before. Before my core was clogged with all kinds of rust but cleaned it out and now water constanly runs through it and keeps it clear. Also I have'nt had any overheating problems since then. Heres the link of how to deal with the plumbing: http://naxja.org/forum/showthread.php?t=993153
 
Last edited:
paulhead said:
Heres the part for the mod http://www.summitracing.com/parts/MOR-63745/
Don't get a cheaper one or you may have probs with the cap mounting surface wearing down and the cap not sealing right. I forgot what cap you get for it though. Here some pics of what my set up looks like.

nana008.jpg

nana009.jpg


I eliminated the heater control valve and all the BS plumibing in there and my heater works killer now, did'nt even heat up before. Before my core was clogged with all kinds of rust but cleaned it out and now water constanly runs through it and keeps it clear. Also I have'nt had any overheating problems since then. Heres the link of how to deal with the plumbing: http://naxja.org/forum/showthread.php?t=993153
Click to expand...

So you are running no pressure bottle now.. I don't want to eliminate all the "bs plumbing" because that heater bypass valve helps the A/C work
better.

About your summit link.. you got one that is 2'' right? 1.25'' seems too small.
 
Last edited:
stephenspann27 said:
So you are running no pressure bottle now.. I don't want to eliminate all the "bs plumbing" because that heater bypass valve helps the A/C work
better.

About your summit link.. you got one that is 2'' right? 1.25'' seems too small.
Click to expand...

Preasure bottle's gone, not needed. I put a generic resevoir bottle where it use to be. You cut the radiator hose and install the filler at the highest spot in the hose as shown. And I used the 1.25" filler for my 90 XJ. don't know if different year jeeps are different , I doubt it. As far as the heater control valve making the AC better, I don't see how one would affect the other.
zandd002.jpg
 
Your right it is 1.25''... the heater bypass valve keeps the heater core from behind heated when the heater is not running, that keeps excess heat out of the heater box/evaporator core area. The evaporator core can do a better of cooling, when it does have a hot heater next to it separated by a thing flap.
 
That is correct, it is only 1.25". I had trouble believing that myself until I measured it.
 
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, the radiaotr cap on the upper hose and in my other Renix cooling problems threads here last year. So far the mods all working perfectly, in 95 F Texas humid heat. I have two caps on my system, the inline standard hose cap, 16 lbs, and the Renix closed system bottle and Volvo cap, with the brass fitting inserted (threaded) into the bottom tube of the bottle (see my other thread on the bottle mods we did last year) and it works fine with no overflow bottle. No leaks, no overflow, in nearly 12 months now.
 
Funny that you updated this.. I just looked this thread up yesterday. I think I"m going to try a crown vic pressure bottle instead. I can probably get it from the same price as the inline filler neck.. and I can keep my heater valve..
 
Dec 11, 2010 update. Still no problems, no leaks, no overheating, no coolant loss. This Fix has stayed fixed now for a good 16 months, with no problems.
 
Update: This inline filler neck is still working perfectly with the Renix closed system bottle, a Volvo bottle cap on the bottle, and the brass nipple added to the inside of the lower bottle nipple for reinforcement on my 87 Renix. Made it through two summers now in record setting 105 F days, in heavy freeway 5 PM traffic for hours with the AC on Max, here in Houston for months the last 2 summers.

Details on the Volvo cap and brass nipple mod/addition are here:

http://www.naxja.org/forum/showthread.php?p=245446432

My peak thermostat outlet temp has been 200 F!!!!
 
You can find the same "T" type radiator cap fitting on V-6 Dakota's in the early 2000 models. My sis has one on hers so it would be a nice/cheap JY upgrade.

Mike I have switched my RENIX over to a "open" system but it was out of necessity. I had to buy a new radiator due to a puncture so I just got a 96 model 2 core.

The closed system is fine but the open system does require less burping during maintenance.
 
With the inline filler neck, I did not need to do any burping at all on the Renix.

And the closed system runs and operates at half the internal pressure (at 200 F) compared to the open system, because the Renix bottle has compressible air/water vapor in the gas space in the bottle! It is easier on the radiator, running at about 9 PSI, than running at 15-16 PSI.

Thanks for posting the alternate cap. The Volvo cap is only $7, new at AZone.
 
Doing this mod seems to be a very easy way to keep the Cooling fan switch on the radiator without having to place it somewhere else with the filler neck open style radiator from the nonrenix setups. Anyone have a line on a place to find the 3 core or large 2 core radiators?

-( thread revive )-
 
Try a search on Ebay, that is best place to look. CSF makes the only good REAL 3 row brass, all metal one. The rest lie about the row count, have plastic tanks, and or aluminum core.....Also search old threads I made on the radaitor sources, I linked them here about 4 years ago in an old thread, but some of them have changed over time.
 
You must log in or register to reply here.

Similar threads

G
Radiator/water pump hose clamp sizes
Replies
5
Views
1K
XJI6191
X
M
Power Steering Return Hose
Replies
5
Views
1K
Musdog
M
S
Issues flushing dirty coolant
2
Replies
29
Views
4K
fenns7
F
Root Moose
Cooling System Reset (2000 XJ)
Replies
1
Views
1K
Rob Mayercik
R
G
Coolant System No Pressure
Replies
9
Views
2K
Woodswanderer
W
Back
Top