In another consequence of the hurricane, we had a thousand-dollar repair bill on the BMW. Though actually, in a sense, the hurricane may have simply made us aware of a problem that had been ongoing.

As you may recall, I was blogging with power out by running my modem and laptop off a voltage inverter hooked up to the car’s battery. On the Saturday morning before we got full power back (even with partial power, I couldn’t get the DSL modem to work from the house current), I was letting it idle in the driveway to recharge the battery, while I watched the (infuriating) Michigan-Notre Dame game.

Suddenly, I heard a loud hissing sound in the driveway. I ran outside and the car resembled a steam locomotive, with its hood obscured by all of the dangerous DHMO in gas phase. I looked at the dash, and the temperature gauge was pegged. I shut the engine off, and let it sit.

The next day, I tried topping it off, and the water was pouring out as fast as it was going in, through a crack in the filler tank that had apparently ruptured.

I tried driving it, and while it ran smoothly, it had no power (top speed about ten MPH), which really started to concern me, because I was afraid that I’d warped or cracked the heads on the V-6 (though that didn’t make sense, given how smoothly it was running).

I also couldn’t figure out how I’d managed to drive it across the country two weeks previously, through the Southwest in the hottest part of summer, with no problems at all, but then have it overheat idling in the driveway.

Then, of course, the little cartoon lightbulb went on over my head. It has an electric fan to pull air through the radiator when the car isn’t moving. Most likely scenario–the fan had failed sometime in the past, and I hadn’t noticed it because I’d rarely let the car idle motionless for that long previously.

Sure enough, when we took the car to the repair shop, that was exactly what happened–a resistor had gone bad and the fan had quit fanning. Of course, the resistor isn’t replaceable–you have to buy the whole fan unit from Wolfsburg, at over three hundred dollars. Also, it was a cascading failure–the incident, in addition to rupturing the plastic fill container, wiped out the water pump by running the bearing dry, and the thermostat. All told, about a thousand bucks, including labor.

The mechanic told us that he hadn’t seen this happen before, but it didn’t surprise him, because BMW had gone to a single, non-redundant fan about that time. I’m not sure why they don’t just drive it off a belt like in days of yore, but I guess most modern car manufacturers prefer to only run it when it’s needed, perhaps to not be a useless power drag, since it’s rarely needed. I know that I have one on my eighteen-year-old Accord that’s never had a problem. And of course, this would have been avoided if I’d been sitting in the car while it was idling, because I probably would have noticed the temperature creeping up (which would have been a much less costly way of discovering the problem than the catastrophic failure that it actually endured). But there’s no telling how long it hasn’t been working, or how long it would have been before I discovered it, if it hadn’t been for Frances.

The good news is that the engine is all right. The power problem wasn’t caused by a lack of compression, but by a slight warping of the throttle body so that the valve couldn’t open properly. After cleaning it, they got it working again.