leaking heater core...or heater hoses...or both?
photos below
1992 isuzu trooper V6 3.2l automatic

after pinpointing 5 weeks ago an intermittent coolant odor to the heater hoses at the firewall, i discovered friday wet carpeting on the passenger side and the driver's side, too.
man that stuff has been sopped up by the felt and insulation backings of the carpet and the sound deading material.
researching here (and there) it sounds to be classic heater core, but . . .after a rediculous amount of time removing parts in order to remove other parts, i've got all the carpeting out and can only find two sources of leaking coolant inside -- both at the inside junctions of where the heater hoses connect on the other side of firewall. --see photo's --

below are some photographs (actually easier to see with the camera than with the on location eye).

questions [color:"red"]
?? when the heater core goes, what exactly goes.[/color] is it the 'radiator' tubes, or is it the plastic tubing that accepts the heater hoses? (which is what actually cracked on my radiator when it went)

??? [color:"red"] where, typically, does the coolant go when the heater core goes. [/color] that is, where does it exit the heater core box. the only coolant leaks inside i can see are at the two places mentioned above and pictured below. (i don't see any coolant at any of the heater box's air tubes.)

the coolant has migrated from those two spots all through and under the carpeting (etc) on the passenger side (as expected), but also over the hump and down into the driver's side carpeting (etc). don't ask me how -- except by wicking or possibly following a harness or ?

naturally, i don't want to replace the heater core box if it really is just the heater hoses, which i thought was the case before i discovered the wet interior. your feedback and photo diagnosis is needed, plus your own experiences with this problem.

engine compartment heater hoses


closeup of heater hoses at firewall in engine compartment û using mirror from below

another mirror closeup


under dash areas of heater box with visible leaks -- both at firewall foam at heater hose 'terminals'.


closeup view of left 'terminal' and sopping wet foam


closeup view of right 'terminal' and it's own little supply of coolant-loving foam sponge


your input is greatly appreciated and needed. i'm especially needing help from those who have replaced their heater cores and can tell me where their coolant actually leaked from, which i hope will lead me in the right direction.

//bc

Coolant can travel up hill and down as you pointed out by capillary force.
Volkswagen had a notorious design gaff whereby coolant could wick from the coolant expansion tank throughout the entire wiring harness due to a poorly positioned probe. More than a few unfortunates discovered coolant dripping out of their tail lights.

Heat cores are thinly constructed for maximum heat transfer. As such anything on them can go. If you are going to the trouble of taking it apart take it all apart and test the core even if you are sure it's just a hose.

yeah, thanks. but i'm trying not (hoping not) to take it *all* apart. i really don't want to take the heater box/core out unless absolutely necessary. i'm hoping it might just be the heater hose at the firewall, which is getting that sponge foam soaked, which is making its way to the interior.
i still don't find any evidence of coolant in the air discharge areas of the heater box. i'm thinking that means the heater core isn't leaking. which would mean that it's leaking at the hose or possibly from those 'plastic' inlet/exit points that are attached to the core for the heater hoses.
i haven't seen one of these except installed, so i'm going from that and from the line illustrations in the helm factory workshop manual.

has anybody seen one of these out? can you tell me where it is known to leak?

thanks for your help'
p.s. Happy Thanksgiving !


//bc

If your carpet is wet on the passinger side your heater core is leaking, so do both hoses and a core. Good luck Don

Yep. mostly when it comes to heater core leaks there ain't no good news. Truth is there isn't a job more frustrating on any kind of vehicle than a heator core replacement. I agree with the owner; try the hoses first. If it helps, great, if not then go from there.
Brian

I beg to differ on that one. I once owned a 77 Ford Econoline and the heater core was in the engine compartment. Switching it out was almost as easy as replacing an air filter. (Considering the rest of the vehicle I'm convinced that the Ford engineers put it there by accident <img src="/forums/images/graemlins/rolleyes.gif" alt="" />)

Unforetunately your issues are exactly identical to mine that I experienced a year ago. I called Merlin at St. Charles and the do not make those cores anymore due to their faulty design. In order to replace it you must replace the entire unit to include the controls. The cost was in the upper $300.00 range and that did not include labor. I still haven't replced mine due to the cost.