Coolant Leak MaxxForce 7 Diesel Engine

imported_John Whelan - February 5, 2016
NOTE: So no one will think I was just dumping coolant on the floor and in to the city drain system and with respect to the EPA....The video showing the leak in question is draining water on to the floor. It's not coolant since it was all lost (somewhere on a barren logging road) at the time of the failure. The water was used to refill the engine block to find out where the leak was coming from.

When I got a call from the driver that he lost all of his engine coolant and it drains out as fast as he can put it back in I thought it could either be the radiator, or a major coolant hose failure. Since the bus was an hour out of town I had to think about the options which were to send 2 vehicles and 2 shop personnel out on a service call or dispatch a tow truck.

Sending 2 people out with a pick up and spare bus is a risk since I didn't know exactly what the failure was on the engine cooling system. They could arrive and see that a particular replacement part was required to repair the failure or the damage was beyond a field repair and calling the tow truck was inevitable. If you hit a wall and can't repair a mechanical issue on the road there will a lot of time lost.

Since the driver could not specifically tell me what the problem was I decided to send out a tow truck from town and be assured that it was coming back to our shop regardless of the failure. When it got to the shop the leak was obvious as pointed out in the video. There used to be a clamp that secured the pipe to the engine block but it broke and created a vibration that loosened the retaining bolt securing the pipe and o-ring seal to the coolant housing.

I know this is simple stuff and not rocket science but when something like this happens we make sure it does not happen again and checking the other engines in the fleet (same model) so this problem does not happen again. Preventive maintenance is the motto in our shop and a 500 dollar tow bill makes us try harder to prevent this from occurring again.

It's actually a good thing that we did bring this bus to the shop instead of fixing it on the road and leaving it out of town. One of the rear shocks was broken on the bottom end and the U-Bolts on the left side of the axle housing were quite loose. This bus runs on a very rough logging road so it's not surprising this happened as well. That red flag pushed us to get it on the hoist and check the chassis front to back for any other loose parts and fasteners.

Diesel Engine
maxxforce 7