93 FZJ80 Rear Heater Hose By-Pass

[Billy Mac]

First time on any forum. I have read a bunch on ih8mud. I am attempting to bypass rear heater hoses. I have encountered (2) hoses off the T from the inflow hose (passenger side) passing through the firewall. I assume one is for front heater and the other for rear heater. Don’t know if top hose is front or rear.
Likewise on the driver side (2) hoses to the T. I am assuming these are the return hoses. Again unsure which is front and which is rear.
I am guessing top is front and bottom is rear, but unsure, and would like to be sure before bypassing.
Also, when looking at heater control valve, the arrow on top is pointing right to left (driver’s side towards passenger side) which seems backwards (from block back towards hoses at firewall as it is. It seems like the direction should be from the return hoses at the firewall towards the block).
I
I would appreciate some help from anyone competent enough to give it.

 

[voodu3]

Download this.

FSM - 1993-1994 FZJ-80 Updated and Combined FSM

IF YOU ARE HAPPY WITH THIS FSM PLEASE RATE THIS RESOURCE 5 STARS! Revision 05 has been uploaded, check out the update I posted detailing the new features added. The previous version of the 93-94 FSM had confusing file names, ridiculously...

forum.ih8mud.com

The first couple of pages shows exactly what you’re looking for.

 

[ppc]

the arrow on top is pointing right to left (driver’s side towards passenger side)

All references to right or left in automotive vernacular is determined from the drivers seat looking forward.

 

[Broski]

Welcome to mud.
First thing we need to know what you working
You can put it in you signature.
And picture are super helpful we are a visual group.

 

[Billy Mac]

All references to right or left in automotive vernacular is determined from the drivers seat looking forward.

1993 fzj80
My assumption is that Heater hose to passenger side firewall carries coolant FROM heater to water pump. I also assume that coolant from the water pump to firewall hoses on driver side carries coolant FROM the water pump to the heaters. Are these two assumptions correct?
Next question: there are two hoses on esch side (driver’s and passenger’s) coming off of Ts. Which hose goes to /from the rear heater, the upper or lower hoses?
I want to bypass the rear heater.
Thanks

 

[Broski]

Simple & the cleanest way to do a rear heater delete !

LCP - Rear Heater Delete Hose

Molded Rear Heater Delete Hose The upgraded installation with a perfectly molded hose.

sites.google.com

 

[Malleus]

1993 fzj80
My assumption is that Heater hose to passenger side firewall carries coolant FROM heater to water pump. I also assume that coolant from the water pump to firewall hoses on driver side carries coolant FROM the water pump to the heaters. Are these two assumptions correct?
Next question: there are two hoses on esch side (driver’s and passenger’s) coming off of Ts. Which hose goes to /from the rear heater, the upper or lower hoses?
I want to bypass the rear heater.
Thanks

Does this help? Red arrows go through the firewall to and from the heater core.

You need to connect the drop (87248C) and the lower tee tube (87248B) together (blue lines). These are the feed and return from the rear hardlines. And do something with the hardlines, of course.

 

[Billy Mac]

Does this help? Red arrows go through the firewall to and from the heater core.
View attachment 3730585
You need to connect the drop (87248C) and the lower tee tube (87248B) together (blue lines). These are the feed and return from the rear hardlines. And do something with the hardlines, of course.

Yes. Very helpful in confirming direction of flow. What the diagram does not address is which heater hose connections at the firewall lead to front heater and which to rear heater. I assume that the top connects to front heater and the lower to the rear heater.
Can’t the two rear heater connectors simply be capped? Why do they need to be connected?

 

[Malleus]

Yes. Very helpful in confirming direction of flow. What the diagram does not address is which heater hose connections at the firewall lead to front heater and which to rear heater. I assume that the top connects to front heater and the lower to the rear heater.
Can’t the two rear heater connectors simply be capped? Why do they need to be connected?

The red arrows are the heater core connections, through the firewall.

The heater hoses at the firewall only connect to the heater core. The drops on the hardlines connect the circuit to the rear heater lines. This should be obvious if you look down behind the head, in front of the firewall - you can see the rear heater hardlines bolted to the firewall. You might need a short step to get up that high.

Yes, you can cap them, if you can find caps. There is pressure in the lines, however, that will constantly try to pop the caps off the drops.

Connecting them with hose is a safer solution. The hose won't pop off the tubes, being held in place by the clamps, and it won't leak.

You can replace the tee (87248C) with a straight pipe, which will solve that problem, but the supply line tubing (87248B) has two drops, and the upper one of them has to be there - it supplies the heater core through the firewall.

 

[Malleus]

These are the firewall brackets for the rear heater hardlines (in blue); this view is facing forward, toward the firewall:

The hoses above them connect to the drops I referenced above. The vertical parts are on the firewall. The remainder are routed under the body.

None of this goes through the firewall.

 

[Broski]

All this has been covered meany times, as well as any question you may have about your 80.
Instead of starting a new thread you can do a search, I like to use Google it will direct you right back to Mud !!

Google Search