Car Doctor Q&A – An International LPG Conversion Conundrum

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We get the occasional question on liquid propane conversion, but we’ve never received one from as far away as Scotland before. But, considering the price of gasoline and the relative rarity of the Toyota Previa minivan, it figures that none other than AAA’s Car Doctor, John Paul, would field the question.

Q, I’m based in the UK- Glasgow City in the southwest of Scotland.  I am in love with the Toyota Previa MK 1 (the odd shaped ones manufactured in the United States and Europe from 1990 to 1999). My dream is to drive a 2.4 liter petrol (gasoline) automatic-transmission version converted on liquid petroleum gas. I have found a 1994 Previa that is already LPG converted but the seller says the head gasket is faulty. That’s the context of my question. This Previa is in my price range but I don’t have the money to have the engine removed and repairs done the conventional way.  I found you mentioned on the internet with a product called Thermagasket from RXAUTO. My question is, does this product work and do you think it would work for a LPG converted engine?

A. I have always been bit hesitant about additives that can take the place of actual repairs; most I have tested have not yielded success. Regarding Thermagasket, listeners on my radio program report about a 50 percent success rate with the additive successfully sealing a leaking head gasket. Now considering repairing the cylinder head-gasket in the conventional manner will take at least 12 hours of labor plus parts perhaps it would be worth a try. Depending on how long this van has been for sale, see if the owner is willing to pay for part of the product cost. This way you are both sharing in the gamble of the repair.