Need help! Cab heater installation on 4120

[OtterBrookStables]

Hi All,

Need some help with a current project. I am going to install a cab heater in my JD 4120 with a CozyCab. Where do I tap into the coolant lines on my motor - I have no clue! Any advice on where to mount the heater in the cab? It's a small universal type of heater with a two-speed fan. Do I need a shut-off valve of some sort?

Any help would be greatly appreciated. Thanks!

 

[AKfish]

Hello OtterBrookStables! That certainly is a nice cab you have on your 4120! I haven't looked at JDParts; but you might get a good idea of the flow direction of the coolant circuit from that.

Ideally, the heater install is not much different than installing an in-line, tank heater (remember those).

Place the heater in series with the direction of the coolant flow from the water pump. You want to intersect the flow of coolant after it leaves the engine (warm) but before it passes thru the radiator (cool).

You don't want to stop the flow of coolant with a shut-off valve, however. Hopefully, the heater instructions will clarify how the warm engine coolant can be diverted in the coolant circuit without passing thru the heater coils.

AKfish

 

[patrick_g]

Two ball valves will do it. One to cut off water flow through the heater core and the other to open up a bypass to let engine cooling water bypass the heater core. If your heater core will not pass enough water to meet the engine's needs the symptom will be higher than normal engine temp indications. In this case just open the bypass valve a little at a time till the temp returns to normal.

In summer you open the bypass valve completely and shut the other valve controlling water through the heater.

Pat

 

[OtterBrookStables]

Hi guys - sorry- been away from this project for a while but now I need to get 'er installed before snow flies.

I've seen dealers install heaters by tapping into the inlet and outlet of the water pump - either using plug holes or drilling and tapping new ones. That way, the heater coil gets a flow circuit that is in series with the engine. Pretty slick - and you can put a shut-off valve inlne to stop the flow in the summer if you choose - though most don't bother.

So, I was checking out my 4120 water pump today and there are a few plugs - two on the top side and two on the bottom on the left side of the tractor. Looks like I can use them - just remove the plug bolt and thread in a hose fitting. Problem is, it's impossible to tell which plug to use (or if they are even plugs at all!). Does anybody have or know how to get an exploded diagram of the water pump so I can decipher which plugs to use? Once I have them identified, the rest is really a piece of cake.

As always - thanks for your help.

OBS