Help - FJ62 - Coolant leaking from Rear heater core

[fj62steve]

Working on installing my new carpet and I notice that there is coolant seeping through my rear floor where the rear heater core connects to my floor. What is causing this? and how do i fix?? I cut the two rubber hoses and removed the heater core since it was leaking all over my floor. Thanks guys

 

[fj62steve]

Or Is there a way to expect the core for problems? Or should I just bypass it? Any tips?

 

[OSS]

Just bypass the inlet & outlet pipes under the car - or plug them.

 

[fj62steve]

Just bypass the inlet & outlet pipes under the car - or plug them.

Cool thank you!!

 

[fj62steve]

Just bypass the inlet & outlet pipes under the car - or plug them.

Hey so I plugged them and now the truck is overheating. Did I do something wrong?

 

[g-man]

You should loop them.

 

[g-man]

You can loop the pipes with a piece of 5/8th heater hose. but I'd do it at the firewall not under the truck.

 

[fj62steve]

You can loop the pipes with a piece of 5/8th heater hose. but I'd do it at the firewall not under the truck.

Okay. I couldn’t find a way to loop them under the truck without it kinking. Now I need to find where I loop it at the fire wall. Do you know where the best spot is?

 

[fj62steve]

this is what i’m working with. Do i plug “green”. And what do i loop?

 

[fj62steve]

My idea was connecting red and blue and plugging the rest? What do i do here if anyone can help

 

[g-man]

Just below that and back on the firewall find two metal lines going down. I'll send you a pic in a minute.

 

[fj62steve]

You can loop the pipes with a piece of 5/8th heater hose. but I'd do it at the firewall not under the truck.

I don’t wanna connect the wrong lines, could you tell me which ones need to be connected?

 

[fj62steve]

Just below that and back on the firewall find two metal lines going down. I'll send you a pic in a minute.

I’ve found those lines they’re the same that are under the rear heater under the truck. I can’t find a hose that doesn’t kink when I loop them together since they’re so close

 

[g-man]

connect these together (see red arrows). The pipes (in green) are the ones that go to the heater under the truck.

 

[g-man]

Ok, remove those two hoses and get a new 5/8th inch piece about 18" long and run it from one pipe to the other. the one on the passenger side is a short piece and goes to a U shaped pipe ...disc it there . The other goes behind the engine but sticks out enough to get the hose on it.

FWIW you may be able to remove your metal pipes that run under the truck and sell them. Many of us (me included) have had them rust out.

 

[g-man]

In blue is where you need to disconnect the old hoses and use a new hose to connect these two pipes.

 

[OSS]

The engine isn’t overheating because those pipes got plugged. Coolant only flowed through them when the rear heater was activated – and the rear heater isn’t a significant engine cooling component.
Granted the rear heater plumbing does increase coolant flow out of the back of the head when the rear heater is open, but that’s not the “normal” circuit the coolant takes.

Looping those two pipes is like connecting them to the rear heater core and opening its water valve, but not using its fan.

 

[ChaserFJ60]

Plugging this hose wont cause your truck to overheat. You probably have an air bubble.


Okay I just dealt with this problem! those rubber caps you have are not reinforced and will pop under pressure within 3 months. Avoid using those for long-term if at all possible!

Its impossible to find a new rear heater core valve, They dont exist. Used ones do but meh.

I soldered on some soft copper to bypass the leaking valve, So its always on full heat 100% of the time. However this is okay if the heater fan is turned off, If the fans not blowing the heat wont transfer to the cabin air at any noticeable rate so its more than tolerable in the summer, In the winter its always been on full anyways. Sorry for the poor quality pictures but heres what I mean

 

[fj62steve]

Okay I did what you said. Truck is overheating still?

 

[fj62steve]

The engine isn’t overheating because those pipes got plugged. Coolant only flowed through them when the rear heater was activated – and the rear heater isn’t a significant engine cooling component.
Granted the rear heater plumbing does increase coolant flow out of the back of the head when the rear heater is open, but that’s not the “normal” circuit the coolant takes.

Looping those two pipes is like connecting them to the rear heater core and opening its water valve, but not using its fan

Plugging this hose wont cause your truck to overheat. You probably have an air bubble.


Okay I just dealt with this problem! those rubber caps you have are not reinforced and will pop under pressure within 3 months. Avoid using those for long-term if at all possible!

Its impossible to find a new rear heater core valve, They dont exist. Used ones do but meh.

I soldered on some soft copper to bypass the leaking valve, So its always on full heat 100% of the time. However this is okay if the heater fan is turned off, If the fans not blowing the heat wont transfer to the cabin air at any noticeable rate so its more than tolerable in the summer, In the winter its always been on full anyways. Sorry for the poor quality pictures but heres what I mean
View attachment 2916489View attachment 2916490

I did the bypass as g-man suggested and it still overheats. How would I get rid of this bubble?