L3901 Heater installation

Snow Dog said:

So, from my reading on this site and talking to some guys at part stores it appears the spot to tap in is Before the thermostat but after the water pump? The return can be at this same spot or after the thermostat?
I have the part number for the elbow but no dimensions on it. I would like to complete this and document it with pics to make this easier for the next person. Everything I am seeing is on smaller tractors with some steps missing from the process.

Any thoughts?

Best place for tees?

Click to expand...

You need to have a takeoff after the water pump and the other one before the water pump. The hottest water is just below the thermostat and that is after the waterpump so any place you can tie in there is ok .( there is a pipe plug just below the thermostat, on the left somewhat rear side) the other hose (return) would be OK tee'ed into the lower rad hose, I don't see any other place convenient to put it.

I used the small bypass hose at the stat. No reason to mess with large fittings. I hooked mine up when I built my cab 5 years ago and there's plenty of hot water. I can be comfy on the coldest night.

Since the heater is tied to the bypass, you need to make sure there's a path for the water. I have valves so the water is either running through the heater, or bypassing it.

There are pics and some explanation starting in post 21 here:

http://www.tractorbynet.com/forums/...ractor-cab-3.html?highlight=thermostat+heater

My heater:

https://www.speedwaymotors.com/Spee...wISHe_jXoU1uDmGZuKjoJymWHuCU9ougaAnokEALw_wcB

EDIT TO ADD: I have replaced all the hoses inside the cab with hard copper. The thought of being in the cab and having a hose failure worried me.

It will be a big job to get at the bypass hose on the L3901, not to mention the bypass on them is complicated because it has an additional hose that goes back to the egr! I think you should leave it alone.

The top view shows both supply and return for the heater. The short, darker-colored hose with multiple bends (runs between the double hose clamps and flange) is factory. The two ends are different sizes. This hose is "Hose A" in the first picture. Since I needed two 5/8" connections for my heater, it was simple to use the existing hose. It provided both an adapter to go from 1/2" to 5/8" and the factory bends made it easy to get out of a fairly tight spot. The flange end is 1/2" and the top end where it is coupled to my heater hose is 5/8". This runs to my heater core through valves that allow me to have flow through the heater or bypass it. The flow is never deadheaded.

From the factory, it was connected to a port where I now have the other heater hose. In its current position it was rotated about 90 degrees clockwise. It's not easy to see in the top view picture, but the other heater hose connects to the port vacated by that short bent hose. That is hidden from the top view by that plate where the bottom of the hood support strut is pinned. If you look at the first picture, the port is where "Hose B" connects.

EDIT TO ADD: Here's a picture of the copper extending out of the Lexan panel. The foggy-looking part at the bottom is an accumulation of Lexan crumbs generated from grinding a notch for the copper plumbing. When the heater was connected with hoses, I was able to fish them around. (Cab is all auto safety glass except below the windshield. That allowed trimming to fit around hood, pedals, hoses etc.)