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4x Forum Editorial

Christian Lee | Writer
Posted November 1, 2007

Send questions, comments, and suggestions to: 4 Wheel Drive & Sport Utility MAGAZINE, Attn: Christian Lee, 2400 E. Katella Ave., Ste. 700, Anaheim, CA 92806, or

Good and Bad of Propane
Comment: I have used propane for close to 20 years on everything from Ford 4x4s to Chevy Suburbans. It has always proven to be a good, clean-burning, reliable fuel. In Canada, the government used to have a program to subsidize the conversion, which it unfortunately discontinued. In some parts of northern North America, such as where I live, propane has one distinct disadvantage: It is always a very cold liquid under pressure which, when released from the bottle, changes into a gas. As long as the outside air temperature is above -42 degrees C (-40 degrees F and -40 degrees C are the same), this change of state can happen. If it gets colder than that, the propane stays a liquid and will always flood the engine. Believe it or not, I have held a Styrofoam cup under the vapor hose and filled it full of liquid propane

The physics works the other way in hotter climates as well. If you run out of coolant in your radiator, the vaporizer will not warm the liquid enough to vaporize it and you'll get a giant ice ball under your hood even at 100 degrees F. You won't turn a wheel - it's just like running out of fuel.Deryle PennerGrande Prairie, Alberta, Canada

A: Deryle, thanks for your response to the propane conversion article ("Samurai Propane Coversion," Aug. '07). You bring up some good points, and our physics lessons from long ago aren't fresh enough to dispute any of them. However, we did speak with Cary Gleason of in Phoenix who reports absolutely no hot-climate issues using the company's systems, provided the engine is well-maintained and in proper running condition (a loss of coolant in the radiator will have adverse effects on gasoline-powered engines as well).

In hotter climes, such as Arizona, Cary suggests filling tanks to 80 percent to allow for heat expansion, and also to have a relief valve rated at at least 170 psi in place so the tank won't become overpressurized. As for colder climes, such as in the Great White North, Cary recommends use of a bottle blanket to heat the propane bottle so that it will build the necessary pressure to convert the liquid propane to gas and power the system. Provided the propane bottle is warm enough to build ample pressure within the system, a propane conversion could feasibly operate in temperatures exceeding -100 degrees F. For more information about propane conversion systems, contact at (480) 430-8033 or

Cooling Questions
Q: Great article on upgrading the cooling system on the 4.0L XJ ("Keep Your Cool," Aug. '07). I'm in the process of flushing my cooling system and have purchased the FlowKooler water pump (I already have one on my CJ) to replace the leaking stock unit. I will also be purchasing the high-flow parts from Turbo City just as you did. I have a couple of questions though.

It says that you had a 180-degree-F thermostat installed, which will give you better gas mileage. I didn't understand this. I thought this would cause the vehicle to run cooler than it was designed to, which in turn would use more fuel as the computer would think that the engine was not fully up to operating temperature.

Also, did the lower radiator hose contain a spring? This is recommended by FlowKooler, and I am having trouble finding this part. If you didn't have a spring installed, have you had any problems with the hose collapsing?

Thank you for your time and keep up the great work on your magazine!William Bakervia e-mail

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