At the Terminal – The Frozen Bus

It’s been really cold here over the last couple of weeks, and last Tuesday I hit my first real mechanical trouble with my regular school bus run.

I had previously dealt with a bus that had mechanical problems, after I had finished my run, I went to exchange my bus with a driver whose bus had broken down (though I had thought I was going to just pick up the kids and take them a couple of blocks to their drop-off location).  In that instance, a mechanic had already been at work on the downed bus, and got it back to running, so I got to drive it back to the terminal, and have it cut out on me on the trip.  All in all, this was a good thing, since it helped the mechanic to pin-point the problem to an electrical connection, and the whole thing was reasonably fast and simple.

My run is one single school in the mornings, and it’s fairly long.  I leave my terminal at about 6:30 and start picking up kids at around 5 minutes to seven.  And then I drive across the city to get to the school to drop off at 8:00.  Then I get to drive back to the terminal (if I don’t help out with another run) and get there around 8:30 if all goes well.  There are, of course, issues – those kids who wait in the house until the bus comes and aren’t ready when it does, the ones who are running late and have to run down the street to get to the stop while I wait, the cars who get stuck and block the small streets who I have to wait for, and the other buses who need to pick up along the same route who I can get stuck behind, not to mention simple traffic and regular accidents that throw wrenches into the finely tuned route that the school board’s program spits out.

At any rate, Tuesday had a fine start.  It was cold (temps in the negative single digits), but my regular bus started up fine.  Traffic was moving slowly, so I was a couple of minutes behind in picking up kids, but they were out and things moved right along.  We don’t have cold-weather ‘bibs’ to cover our radiators, and my coolant temperature never got above 155 degrees (this is significant on the one hand because it means that the bus never really warmed up inside, and on the other it indicates how cold it was for the bus’ systems.  The ‘bibs’ limit the airflow over the radiator and allow the bus engine to warm up more).

After picking up all my kids and driving the long way to the school, the engine seemed to lose some power when accelerating.  Not a lot, and not steadily.  In driving stand-by and when my regular bus was in the shop I had driven other buses, and some were full of vim and vigor and others were rather sloppy and lethargic, so I knew there was a range, but this was my bus, and it didn’t do stuff like that, so I was careful with it.

By keeping a slow acceleration and a light foot on the pedal, I could get the bus up to 30 mph (city speed limit), and ride along fine, so I kept on to school, though it seemed to be getting a bit worse.  I called in when I was five minutes from school, to make sure our dispatchers knew, and if it was serious, they’d advise, though I said that I was continuing on to school, and they were okay with that.

I made school and unloaded safely, and called in to the terminal that the engine was getting a bit worse and that I was headed back.  I would usually have taken an expressway back to the terminal, but decided that I wouldn’t today, since the bus was acting strangely.  The temperature of the coolant was hitting a max of 150 degrees, and I was wondering if it was just being too cold for the engine to fire on all cylinders, especially since I was now noting a cloud behind the bus (as I could give more attention to the bus without paying attention to the kids).

And the bus was getting worse.

My route back along the city streets took me over a raised bridge over some train tracks, and I could barely hold 5 mph on the incline.  I was ready to call it in, but on the downside of the bridge, the engine seemed to pick up some power, and I got the bus up to 25 mph and decided not to call.  But a few blocks later, I was coming up to an intersection (behind an already stopped truck), and as I stopped the bus and the engine idled, it died.  I tried to start it a couple of times, and while the engine would turn over, it wouldn’t catch.

The air brake went on, the flashers went on, and I called in that the bus had died.  I verified that I had no kids on the bus, and our dispatchers called to the mechanics to have them send someone out to me.  I dug out the reflective triangles and pulled on my coat, and watched for traffic before stepping off the bus to put a triangle in place.  Now, that might strike you as odd; why would I have to check?  Wasn’t I already at the curb?

Well, no.  The street that I was traveling along had not had it’s sidewalk cleared, and so there was a person walking in the street, and one of the understandings of the bus drivers is that ‘the other guy always has right of way’, so I was far enough from the curb that small cars (and even a small van-based bus that didn’t mind taking limbs off of the curbside trees) could pass my bus on the right, as long as they were willing to brave the snowbank and an angled car.

I ended up waiting almost 30 minutes. Finally, a mechanic showed up with a ‘tool bus’ (a little van bus with a massive battery pack for jumping buses and tools and such), and got to work on the engine.  A quick diagnosis was “water in the fuel line”.  As he got to work on opening the hood and then a filter atop the engine, I boggled for a moment about how, if it was so cold, I could have even started the engine and had the bus run fine for so long on the run with water in the fuel?

Then I remembered about one of the things that’s different about a diesel fuel system than a gas system that I had to pay attention to for a WVO conversion:  the diesel engine doesn’t use all the fuel that the pump brings up to the fuel rail.  The excess is returned to the fuel tank, so there’s a constant flow of fuel round the system and for WVO, it’s important because running the fuel by the engine heats it and when switching between WVO and diesel, you need a delay to clear the line of the other fuel so you don’t mix them in the same tank.  For my bus that morning, it was only the heating aspect that was important.

Aha! Over my run, the fuel in the tank was slowly being heated, despite the mass it had and the non-insulated tank, to the point where it could melt the water that had obviously been turned to ice in the cold.  Thus, it was a delayed problem.

At any rate, despite the two bottles of additive he put in the filter holder and the time spent cranking the engine (about 40 minutes time in total) we ended up having to leave the bus to have it towed.  It felt bad leaving it like that, but there was nothing to do for it.  The mechanic said that there were two filters and the second one was under the engine and the water had probably hit it and refrozen there since it was so cold.  The only real remedy at that point was to bring the bus into the shop and thaw it, then add more additive to the fuel to the system to absorb the water.

 

After having my own bus, and working on it myself, the policy that drivers can’t open the hoods of their buses (not even to add more wiper fluid or open/close coolant flow to the heaters) is so frustrating.  I can’t say what engine I have in the bus, and my view from the windshield while the mechanic was working on it was pretty poor.

At any rate, it was a new and different experience.

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