The Easiest and Cheapest Open Cooling System!
For less than $100.00!

by Joe Thompson
Posted: November 2, 2001
Last Revision: September 1, 2003

I came up with this conversion after I learned the differences between an open sytem and a closed cooling system. I had already done the standard replacements (T-stat, 3-core GDI radiator, flushed the system twice, fan clutch and new pump). I also changed out the sensor in the radiator. I still was not happy with the marginal cooling I was getting. I then found www.jeepsunlimited.com and learned more about the details regarding the differences between the two. There was no way that I was going to buy another radiator to make this switch. The basic difference is having a radiator cap, heater control valve and a overflow canister.

Hmmm... someone must make these. I found what I needed at www.jegs.com and soon had my fix. I no longer had a system that wouldn't work whenever there was a small leak somewhere.This conversion should work on any Jeep with a closed cooling system in it. I wished that I had figured this out sooner, but I'm glad that I did. So far this conversion has worked very well and I don't have the burping problems that the old system has.

The Parts:

Misc Parts: $25
Heater Control Unit: Local Dealer, $34.00

Jaz Coolant Catch Bottle.
Jeg's Part #: 547-600-025-01, $15.99

Moroso Radiator Filler Neck.
Jeg's Part #: 710-63745, $22.99

The Procedure:
1. Cut upper water pump hose in appropriate spot.
2. Insert filler neck into hose (pre-lube the neck with some light grease). Clamp it down.
3. Drop coolant can in airbox corner, attach hose from bottom of can to neck.
I eventually routed my drain hose beneath the radiator top mount plate. Also I switched the coolant can's hose connectors around for better use.

Helpful hint:
Grind down the ridges on the filler neck for an easier installation. Make sure that you shove the hose on all the way the neck. Also do not place clamps near the edge, push them back to the neck. Your hose can be cut from the pressure of the clamp on top of the ridge!

Filler neck installation location.

Jaz bottle loaction.

Heater Control Flow Diagram
[Large Image]
After I did this conversion, I enhanced my cooling more by adding a HESCO water pump and a hood scoop. There is a bit of info on my site about both. I am continuing my pusuit to build a custom overkill cooling system by expanding my cooling capacity by another 2 gallons, as well as adding Grand Am hood vents. Cherokees tend to run too hot naturally, so it's time to change their nature.
©Copyright 2001 Joe Thompson
All Rights reserved.
Photos: Joe Thompson

 

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