Engine Auxiliary Heating Tube Insulation
Planning Ahead For Temperature Extremes
When designing an exploration truck, one that's guaranteed to be used in extremely cold climates (like our Canadian winters), it's important that it be built with a way to have the truck engine heat the camper section when driving (this saves fuel), and then have the camper's boilers heat the truck engine overnight when it's not running. Otherwise the truck might be difficult to start on those frigid sub-zero mornings.
This capability was something that we designed into our build, and it was installed by the body builder. There was just one small problem. The distance from the boilers up to the truck engine is about thirty feet. So the heating fluid has to travel through sixty feet of 3/4" heater hose during its round trip journey from the rear of the truck to the front, and then back. Since the insulating factor of a 1/8" wall thickness of rubber isn't very good, the fluid can loose pretty much all of its heat through the walls of the tubing as it travels over that distance. And since this tubing runs outside of the camper box, along the truck frame, it's fully exposed to the frigid conditions in winter. So like everything else exposed to the extreme cold, it needs to be insulated to retain its heat.
We had to cut the mesh in order to remove it from the hoses running from the boilers to the engine.
Unfortunately for us, the so-called "experts" at our body builder didn't seem to think about that. They ran the sixty feet of tubing without any insulation whatsoever. Oh, they did wrap the two hoses in a fibreglass mesh covering, for what reason we can’t imagine, but it provides no protection against heat loss whatsoever.
The result of this was that our boilers had a very hard time trying to keep the engine warm. In fact, if you held onto the hose up at the front where it connects to the engine, while the boilers were in full burn, the hoses were barely warm at all. So heating the massive 2,800 pound engine was pretty much impossible.
Dealing with The Builder’s Obvious Lack of experience
Leaving the heating hoses un-insulated simply wasn’t an option. We had to have an efficient and effective solution in order to safely use the truck in all weather conditions.
The heating hoses were captured by the heavy steel brackets securing the hydraulic lines.
Unfortunately for us, the builder’s decision to encase the heating hoses inside a fibreglass mesh covering made our insulation job much more difficult and involved. You see, when the builder installed the heating tubes, they did it before the body was attached to the frame of the truck. So all their work was done from the topside of the frame. To make matters worse, they snaked the hose through the heavy steel clamps that were used to hold the hydraulic hoses for the front drive system in place. This meant that simply slicing the mesh casing and pulling it off the hoses couldn’t be done because we couldn’t easily remove the steel clamps. They too were installed from above the frame before the box was installed.
A section of old hose pulled out from the back of the truck.
Doing the job right
As with other things done by the builder, in order for us to make it right, we had to completely remove their work and replace it with our own. This meant clamping off the hoses at the engine, and then cutting the hoses and stripping them out of the frame. Fortunately, we were able to cut the hose in front of the steel clamps and then pull the hose from the back of the truck to draw them out from under the steel hydraulic hose clamps. We could have just left the old hoses in place and ran the new ones via a different route, but we wanted a clean installation. Besides, the insulated hoses wouldn’t fit under the steel clamps.
The thread together poles can be seen resting on the bumper.
New Hose Installation
We didn’t want to patch together a replacement hose run from the pieces of old hose, so we bought some new hose. It’s relatively cheap, and comes in fifty foot rolls. This fact makes one wonder why the builder had to put splices into the original run. Are they really that cheap?
The 6 foot lengths of hose insulation.
Our objective was to have a continuous hose run all the way from the back to the front. To make this easy for us, we attached the new hose to a simple, thread together pole which was slid along the top of the truck frame. The hose could then be pulled from one end to the other.
With a clean, unobstructed run of hose, it was easy to install the six foot long lengths of insulation by simply sliding it over the hose from the back of the truck, and pushing it forward one length at a time. The joints between the lengths of insulation were joined using a waterproof duct tape with zip ties overtop for extra measure. The longitudinal slice in the side of the insulation was held together by its own pressure sensitive adhesive tape. We simply had to remove the yellow covering strip and press the edges together.
The duct tape applied at the end of a run where it Ts into the engine lines.
The two new insulated engine heating hoses (on the right), tied up nicely to the frame cross members. The two hoses on the left are the front drive axle hydraulic lines.
In for a penny, in for a pound
Since we had the heating system pulled apart anyway, we decided to finish the job properly by also insulating the other hoses that ran outside the camper body. Primarily this involved the heating lines that went from one side of the truck, and the boiler located there, to the other side of the truck where it joined with the second boiler. It also included the hoses that ran from the boilers to the black water tank, and keeps it from freezing in cold weather.
