Is this from heater core or connection through firewall?

[Doubledecker]

96 fzj80. Coolant leak is coming down from behind rubber mat against firewall. See picture. Bottom of heater core box and all I can see around it looks dry. Has anyone seen a leak showing in this location and have a good guess at where it's starting? Is this basically a heater core replacement regardless? Appreciate any guidance I can get. Thanks.

 

[60 toy ota]

Is this basically a heater core replacement

Yeah or at least removal to repair. It should be clear at that point where it's coming from

 

[Kernal]

If you're really lucky slim chance it might be the end of a heater hose on the firewall side leaking/spraying the coolant rearward possibly getting past the grommet in the firewall.

Or, a leak from the heater core pipes on the cabin side of the firewall. IIRC the early models had the pipes soldered or braised to the core and the later models (?95+) had the heater pipes attached to the heater core by a factory clamp with an O-ring in between.


Was any work done on the radiator/cooling/heater system prior to the leak ie: Flushing the cooling system?

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Previous discussion on heater core pipes (AFAIK pipes are NLA so if you replace the core you reuse the original IN-OUT pipes)

Thread 'Heater core inlet/oulet pipes question.'

Feb 28, 2015

Vehicle is a 1994 fzj80.

I just replaced the rubber coolant hoses to the inlet and outlet of the heater core and now I have a substantial amount of coolant leaking onto the passenger floor. When removing the hoses I cut them with a razor, but I still had a hell of a time removing them. The passenger side hose, specifically, was vulcanized to the brass nipple on the firewall which resulted in lots of pulling and twisting trying to remove it. My question is how are the brass nipples attached to the heater core? My FSM is worthless (or i'm looking in the wrong spot) for this information. I...

• BlueCruiser84
• Replies: 21
• Forum: 80-Series Tech

Heater core replacement thread:

Thread 'Heater Core Replacement-Pictures and How To'

Feb 22, 2020

Hey guys,

So I just finished up a heater core replacement and I thought I would do a write up and add some pictures of the process. I want to start by saying I do not consider myself a mechanic. I have had my LC for almost a year now and learned how to do a lot to the LC since then (mainly from write ups on here). Before owing my LC I didn't work on vehicles very much. My knowledge consisted of changing my own oil and an alternator replacement on other vehicles I have owned. I say all that to say, if I can do this anyone can.

At first this job seems very intimidating but I really didn't...

• ScubaSteve80
• Replies: 18
• Forum: 80-Series Tech

• 

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Heater core parts diagram: (core #: 87107-60270

 

[Doubledecker]

If you're really lucky slim chance it might be the end of a heater hose on the firewall side leaking/spraying the coolant rearward possibly getting past the grommet in the firewall.

Or, a leak from the heater core pipes on the cabin side of the firewall. IIRC the early models had the pipes soldered or braised to the core and the later models (?95+) had the heater pipes attached to the heater core by a factory clamp with an O-ring in between.


Was any work done on the radiator/cooling/heater system prior to the leak ie: Flushing the cooling system?

-------------------------------------------------------------------------------------------------------------------------------------------------------
Previous discussion on heater core pipes (AFAIK pipes are NLA so if you replace the core you reuse the original IN-OUT pipes)

Thread 'Heater core inlet/oulet pipes question.'

Feb 28, 2015

Vehicle is a 1994 fzj80.

I just replaced the rubber coolant hoses to the inlet and outlet of the heater core and now I have a substantial amount of coolant leaking onto the passenger floor. When removing the hoses I cut them with a razor, but I still had a hell of a time removing them. The passenger side hose, specifically, was vulcanized to the brass nipple on the firewall which resulted in lots of pulling and twisting trying to remove it. My question is how are the brass nipples attached to the heater core? My FSM is worthless (or i'm looking in the wrong spot) for this information. I...

• BlueCruiser84
• Replies: 21
• Forum: 80-Series Tech

Heater core replacement thread:

Thread 'Heater Core Replacement-Pictures and How To'

Feb 22, 2020

Hey guys,

So I just finished up a heater core replacement and I thought I would do a write up and add some pictures of the process. I want to start by saying I do not consider myself a mechanic. I have had my LC for almost a year now and learned how to do a lot to the LC since then (mainly from write ups on here). Before owing my LC I didn't work on vehicles very much. My knowledge consisted of changing my own oil and an alternator replacement on other vehicles I have owned. I say all that to say, if I can do this anyone can.

At first this job seems very intimidating but I really didn't...

• ScubaSteve80
• Replies: 18
• Forum: 80-Series Tech

• 

-------------------------------------------------------------------------------------------------------------------------------------------------------

Heater core parts diagram: (core #: 87107-60270

View attachment 4125612

Some great info. Thank you!
PO replaced hoses maybe 3-4 years ago. I tightened the hose clamp right at the firewall on the engine side and it seemed a little on the loose side. This seems to have significantly reduced the flow but there still seems to be a little seepage coming down and it's now pretty tight. Really hoping this is it, but the info provided gives me some confidence I can tackle the heater core if I have to.