Please confirm un-plumbing of rear heater

[john_eckels]

My rear heater lines are badly rusted under the second cat. I found a thread the explained the procedure for un-plumbing the rear heater. Before I start chopping stuff, could someone please confirm that I have picked the correct connections to keep and discard? Thanks in advance for your help

 

[landtank]

yes, that should do it.

 

[john_eckels]

It did it - Thanks. I got a CEL code immediately after doing the work. I thought C-Dan heard me swearing at the thing and hex'd me. Those heater hoses are a pain to get off. It was my old friend P0401. I pulled a line off the modulator when I was tearing out old hose.

 

[gisham]

what size hose did you use?

 

[Pskhaat]

Yes, I don't know why I'm confused on this. Exactly what hoses did you bypass/connect?

 

[medtro]

Yes, I don't know why I'm confused on this. Exactly what hoses did you bypass/connect?

To bypass the heaters, connect the hose as shown in yellow line in the picture.

 

[80t0ylc]

To bypass the heaters, connect the hose as shown in yellow line in the picture.

Medtro, just for the record, your yellow line would bypass both of the heaters. He only wants to bypass the rear heater so his red lines are correct. The green lines in john_eckels photos show the custom cut hoses that need to be added after removing existing short hoses and metal 'Y' junctions.

Pskhaat, I've already done this mod and as a temporary fix before doing the bypass, I bypassed both heaters as Medtro suggested. It was a bad idea for me even though it was summer. It would have been worse had it been any other season. But, for you, even Arizona has it's cooler temps and with no way to put heat on your windshield and occupants you will kick yourself for bypassing the front heater system. To bypass the rear heater is not that difficult to do and actually simplifies your heater hoses. You end up removing two metal 'Y' junctions & short hoses and custom cutting two new hose lengths to reach existing connections. In other words, two hoses have to be longer because of the parts eliminated. You're trading six short hoses and two 'Y' metal junctions for two custom cut hoses - length determined by you when you do the bypass.

As far as the metal tubes and hoses under your rig that connected your rear heater up that will now be unused, you can either drain out the coolant or just ignor them. I drained mine and removed what I could. The pair that come down from the firewall over the tranny bellhousing can be extremely difficult to remove unless engine/tranny is removed. At least if they're drained, they won't drip coolant if and when they rust through. Here's a few threads that will help you on this bypass:

https://forum.ih8mud.com/80-series-tech/286209-need-pics-rear-heater-bypass-firewall.html

https://forum.ih8mud.com/80-series-tech/150466-rear-heat-bypass.html

https://forum.ih8mud.com/80-series-tech/216813-bypassing-rear-heater-hoses.html


Also a good site with a diagram of all heater hose to refer to:
ExpeditionLCMajorcoolingoverhaul

 

[scottm]

A pic of my bypass is at the end of this thread https://forum.ih8mud.com/80-series-tech/216813-bypassing-rear-heater-hoses.html

 

[97lx450guy]

Anyone know what sizes hose for rear heater bypass fj80

 

[graham5david]

just follow this

 

[jfz80]

Its bound to be in the several avail threads in this post or in FAQ. IIRC 5/8" works well. OEM was slightly different. Probably 13mm or something ridiculous.

 

[97lx450guy]

Ty guys had bypass hose blow left stranded

 

[97lx450guy]

Re plumbing and new pipe for phh and hose bypass number one

 

[graham5david]

just bypass the pipe on the phh it makes the job 100x easier.

 

[97lx450guy]

just bypass the pipe on the phh it makes the job 100x easier.

I agree bypassing rear heater too

 

[97lx450guy]

Those lines look rusty in rear

 

[jaymar]

just bypass the pipe on the phh it makes the job 100x easier.

NOW you tell me. I feel like I've gone 15 rounds with Apollo Creed.

 

[kevsta]

here's mine in silicone, left the metal pipes there, gotta be able to use them for something else, surely..