I'm going to replace my leaky radiator today, along with the thermostat, water pump, hoses, etc. I'm thinking about adding an in line filler neck to the top radiator hose and going to an open type system and do away with that bottle and heater control valve.

Any advantages/disadvantages to this? Should I just keep the closed system? I'm not having any problems with it. I'm only replacing the radiator because it has a slight leak. The rest of the stuff is preventative.

 

After three pressure bottles and numerous caps for the bottle I changed to open system . Have had no issue since doing this .

 

Replace the bottle with one from another car like a VW or another jeep. Closed systems are nice when working properly and air in the system is usually a non issue.

 

If I hadn't recently replaced the radiators in both my Jeeps, I would do this. There are radiators made with the filler neck and the location for the radiator switch so you can use them easily in a Renix.

The problem I have is that the replacement bottles for Renix don't last long at all. Yes, they have a lifetime warranty, but a lifespan of less than 2 years is nuts. I just noticed last Saturday that BOTH my Jeeps had cracks starting on the top of the bottles and were seeping.

 

I bought a filler neck, and installed right next to the AC unit, that's the upper part of the cooling system, and allows the system to auto burp any bubbles that were trapped, bought an radiator auxiliary bottle from another car and installed where the RENIX OEM bottle was, no trouble at all since the installation

What I did not like about having a filler neck on the radiator, is that there are points higher than the radiator, therefore my thinking is that there will be always bubbles trapped in the upper hose! (sounds logical for me but do not know for sure)

anyway the filler neck I got was cheap, bought it from JEGS, and just cut the upper hose in the right spot and installed the new system! so happy and easy!

 

U've got to have a bottle regardless of what cooling system u use (open or closed). Open system will not cool better than a closed system. It seems that the open type bottle is less finicky than the closed type bottle.....easier to just hold coolant vs hold coolant and pressure.


The problem that can/may occur with locating the filler neck/rad cap close to where coolant exits the motor is, coolant flow pressure from the water pump can/may momentarily push the relief valve in the rad cap open allowing coolant to escape thus creating a low coolant condition while driving. That's why with "open cooling systems", auto manufacturers locate the rad cap as far away from the water pump as possible.

 

I have a replacement for when it gives up, but on my Renix that I have owned since 2008 the bottle is still fine.

 

If you want to convert to an open system and have to replace the radiator anyway, it seems to me that it is a no-brainer to just get an open system rad and be done with it. A separate in line filler neck is just another something you have to install and a potential leakage point.

Air does not get trapped in a properly installed and functioning open system with the filler neck on the rad and the system self-burps any air.

You can do away with the HCV on either system.

 

I switched to open when I replaced my radiator.
Ever since had no issues.