Thermostat Housing On The Series 60

This week my team was assigned to work on the FLD Freightliner which has a Series 60 engine in it. Our first task was the testing of various sensors, starting with the engine coolant temperature sensor. This meant draining the coolant and pulling the thermostat housing off the engine.

The coolant is drained either at the driver's side radiator drain valve on the bottom side of the radiator, or a drain plug on the bottom radiator pipe. We drained it at the latter, and my suggestion if draining it here is to wear safety glasses and be ready to get out from under the truck quickly as it will pour out fairly violently. Coolant doesn't taste very good, for the record.

Next we began pulling hoses off the thermostat housing. There is one hose which goes to the upper radiator, another which goes in the side of the thermostat housing from the water pump, and another small hose with a 14mm fitting that runs out from the top to a fitting on top of the radiator.

A lot of hoses and pipes!

Drain pans, not a very good picture. That tire step makes climbing up on the truck easy!

Thermostat housing with the upper radiator hose removed. Note heat shrink clamps, this is the first time I encountered one.

My reflection:

I have worked on this engine before but one thing that struck me was the replacement of the old, often-seen worm and spring clamps with a new heat shrink type. I had never encountered this type of clamp before. To remove them you have to heat them up with a heat gun and cut them off with a knife.

These clamps, although not reuseable, are supposed have a better clamping force than traditional clamps. Will we perhaps see more and more of these on newer trucks and use them as replacements whenever we work on the hoses of older trucks using traditional clamps? Time will tell, but I definitely learned something new this week!