On July 11, 2004, at the Porsche 928 Owner’s Club International Convention in Wichita, Kansas, a friend told Louie Ott that the first sign of a problem was when he spied a slight tongue of orange flames suddenly poking out from underneath the right front end of Louie’s 1987 S4. It was followed almost immediately by the whump of a hood-bending explosion, a red-orange ball of flames shooting out from under the car and clouds of smoke; lots of smoke. All this as Louie, trying to gauge his distance from a nearby fence, was very slowly backing out of a small parking area.
So what the heck happened?
Louie’s total memory of the event is not as crisp and clear as he would like, but he does remember his first indication of a problem: the sound and sight of a white vapor streaming and hissing out in front of the hood. His thought at that time—but only for a very short period of time—was, “Oops, looks like a coolant hose broke.” But then came the BOOM, and it became obvious to Louie that his A/C refrigerant was burning, and that he’d better exit the vehicle.
But let’s let him take over the story. Here’s his email message to Cool Profit$ Magazine of July 15th.
Louie Ott: “Recently, I installed a replacement compressor and new hoses. The low side hose was 2 or 3 inches too long. This extra length caused the hose to have an “S” bend that put it close to the electric fan blades. I tied it back so there was ample clearance.
I have used Enviro-Safe™ as a refrigerant before, and liked the performance. Plus I liked the fact that it was environmentally friendly should it ever leak from the system. My S4’s system is designed to use 37 oz of R12, so I installed the recommended amount of Enviro-Safe: 12 oz (two 6 oz cans).
On the way to Wichita, from my home in Oregon, I threw a belt from the compressor during a period when the A/C was off. I had the belt replaced in Salt Lake City and the mechanic expressed concern regarding the too long suction hose and it’s proximity to the fan and compressor pulley. It appeared that when the belt finally slipped off, it took out some of my nylon tie straps. There was also some scuffing on the hose from the fan and where the hose had slightly rubbed the compressor pulley. Not much and not serious at that time. He tied it back even more securely than I had. We couldn’t see why the belt had come off. The compressor and crank pulleys were aligned and tension was ok. We speculated that a loose breather hose end might have gotten into the belt.
There were no further problems until the dyno runs at Wichita. On the first run, the belt threw again. I can’t be sure, but I suppose it snapped or stretched the tie straps and let the hose contact the fan. I did three more dyno pulls and the hood was closed. The car was unstrapped and I backed out of the building.
Soon after, I heard the rapidly escaping refrigerant. I thought I had blown a coolant hose until the explosion and fire, and then I knew what it was. The pictures tell a good story of what happened and it would have been a huge disaster if it had not blown where it did. There were several car enthusiasts around with fire extinguishers in their cars. It took 5 or 6 extinguishers to get the fire out. I was out of the car with my extinguisher quickly, but others were already on it before I got around to the front.