By Rick Cogbill a.k.a. Slim Shambles
All technicians have their likes and dislikes. Tooner likes tough diagnostic problems, whereas Basil likes donuts, especially the ones with sprinkles. But they both agree on one thing; they don't like propane!
A propane-powered 1980 Ford 1-ton was recently towed in, with the complaint of a fuel leak under the hood. Looking around for volunteers, I discovered that Tooner had to use the washroom, and Basil was already whistling away on the wash rack, soaping down my Explorer. That left me and The Bean.
Grudgingly, Beanie opened the hood, and cranked the engine. To his surprise, it ran great. For about a minute, and then it stalled. But no propane leak.
“So when do I blow up and go to heaven?” Beanie asked nervously.
“Relax,” I said. “Just try it again.” A couple of starts and stops later, we had coaxed the old relic into the shop.
Once inside, Beanie suggested a new propane filter. “It feels like we’re not getting enough fuel.” He went to shut off the main valve on the propane tank and discovered that it was almost closed tight. “No wonder it won’t run!” he exclaimed.
“Probably been turned off because of the propane leak,” I ventured. But when he opened the valve, there was still no sign of a leak.
“I think somebody’s pulling our leg,” huffed Beanie, much braver now. He started the truck and let it warm up. “There’s nothin’ wrong with…” At that moment, the engine stalled as the raw propane began spewing out of the air cleaner. The propane converter became a ball of white frost, as liquid propane rushed through it unchecked.
Closing the main valve again, I did a staff check. Tooner’s ratchet lay on the floor where he’d dropped it in his haste to vacate the building. Basil was now hand-waxing my truck with such vigor that I feared for the paint job. And Beanie had a death grip on the steering wheel, afraid to move.
“Wha…what was that!?” he squeaked.
I chuckled. “The propane system just saved the engine from overheating.”
“How?” said Beanie. “By giving it frostbite!?”
“No. By responding to a problem, such as insufficient coolant.” We checked the coolant and discovered that there wasn’t any. Without engine coolant to heat the propane converter and assist in vaporizing the fuel, the internal valving freezes up, causing the engine to stall. In severe cases, the converter sticks open, allowing propane to leak out.
Beanie filled the radiator with coolant, after tightening the loose hose clamp that started the whole mess. Soon the Ford was purring like a kitten. Looking out the window, I saw Tooner circle the block on his fifteenth test drive. Basil was shampooing my carpets at the far end of the parking lot.
“Hey Boss,” said Beanie, “this truck runs pretty smooth on propane!”
“It’s a great alternative fuel for some vehicles,” I commented, “but you’d better park it outside. At this rate, we’ll never get any work done today.”
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