Duck Vader

Been a Jeep owner for many years and never actually joined this forum. Currently running into some rain water leaking issues with my 98 XJ that I have had for 12 years now. Started leaking a couple months ago and only happens with heavy rains. Did some searching and I found a lot of threads on various sites in regards to the intake cowl leaking. Most of the info I found didn't really address if the water was leaking INSIDE the heater box, or was dripping down the outside of it. I am having water leaking down the inside back of the box. So I am assuming this should be a heater box intake leak issue?

So...

Pulled it into the garage last night to let things start to dry out so I can work on it and put in some sealant.

Removed the cowl and got my phone into there to take some pictures:

Hard to tell in this one, but looks a little damp around the base of the plastic intake.



So I zoomed in and got some better pictures. You can see it is damp around the base of the heater air intake.





However, since that is the best I can see, I really can't tell if water is actually getting down in or around it. I am guessing it might be leaking in water at the back side - you will see why I think that below - but hard to tell in these pictures. Might need to cut into the sheet metal and remove it in order to get access. Will have to put a new piece of metal or plastic over the hole with a **** ton of sealant to make sure it doesn't leak if I go that route.

I went inside the jeep and removed the plastic cover under the dash that was filling up with water.

Noticed water was dripping from the bottom of the blower motor resistor.



Pulled that out and saw a nice and dirty/rusted resistor.



This is the hole the resistor goes into. You can see where the water is dripping down. This confirms water is definitely coming down INSIDE the heater box.



Out of curiosity I removed the glove box to take a better look at the heater box and found some water leaking through it along the end (first picture) and behind/along the wires on the right side of it (2nd picture, hard to tell). Guessing this is just water seeping through to the outside from inside the box?





So I am thinking my first step will be to cut into the cowl sheet metal and access to plastic air intake and put a bunch of sealant around it? Or is it truly better to suck it up and remove the dash? Also going to put a bunch of sealant around where the screws hold the cowl cover into place. Saw online that if those leak they sometimes drip right into the intake.

Also going to of course replace the resistor and put as much sealant as I can in various areas known to leak.

Hopefully that stops this thing from leaking.

Jeepwalker

Ok, I see what you're saying. First question I would ask is, are you parking your XJ on an incline? Especially tilted so the pass side is down?

I'm trying to remember here, others please correct me if I'm wrong .... but from what I remember, if you were to remove your heater box and put your hand above the hole where the air enters from the cowl, what I noticed (on mine) is that there's a lip about 1/2" high (upwards) which means that water would run around the hole, not just drain into it. But if there were debris or something that would 'lift' water up ...or so much water that it overflowed the lip, then it might be able to over-flow the lip and drain down into the heater box. If a vehicle was parked level it shouldn't do that. Most vehicles I've worked on had a 'lip' stamped in the cowl which makes water flow around the hole ..not into it.

Another thing you might try is to remove the wipers and remove the cowl trim and put your hands down there and see what you can feel, or put an inspection camera in there so see if there may by any caulking that has dried and cracked. Also, is the rubber gasket in place between the firewall and hood (to help drain water away)? Ensure all gasketing material between the heater box and the firewall ...and any hoses, etc has integrity. Ensure there are no leaks around the windshield. On my Land Rover, I have a windshield leak which comes down onto the underside of the dash. I need to address it. On my XJ, (this is pretty common, but may not be YOUR problem), the plastic/rubber grommet/seal under the front roof rack support (the part that bolts to the roof above yer head) gets weak and doesn't seal. Water can drain through the hole down to the windshield or the A-pillar. Is the condensate drain plugged (not that it matters in your case, but worth checking). A lot depends how the vehicle is parked.

Ultimately it's not that hard to remove the dash and heater box. You don't need to remove the entire dash, I'm sure you got that from the videos. What you need to do is unbolt it, then lift the pass side up. I personally wouldn't tie the pass side up with a rope ....like some videos show. That to me puts a lot of unnecessary stress on the driver's side of the dash. Just put a stick or bar of the appropriate length under the dash to hold it up enough (and no more). to get the heater box out. But in my mind, I would check all of those other things first. If your cowl hole has a 3/8" - 1/2" lip, water is getting in somewhere. I'd start with the other areas you haven't considered yet maybe get an inspection camera up there before I did any cutting.

Duck Vader

Ordered an inspection camera today. Should be here this weekend.

When it sits outside it does sit on a slight hill. Nothing really steep, but it does face "uphill". Before I cut I am waiting on that camera then I am going to put a lot of water over everything and see if I see where the leak is entering.

Jeepwalker

I could envision how water, after a rain, or melting snow might flow back towards the back of the hood, down the firewall (if it's not sealing well back by the hood/cowl, and drain onto the HVAC lines/Heater hoses, and work it's way into the box. On mine, that junction where the lines enter the box is the least well sealed part of the box. You might have the updated heater box though. There is supposed to be (on some XJs) a rubber strip that fits when the hood is closed to keep water out. Can you see if any water is getting on the firewall? Are there any screws NOT in place along that area? What happens when you park it the other direction.

Don't discount the windshield leak idea, or roof rack mounting holes. If you take off the cowl trim, can't you see down inside there with a mirror? I honestly haven't tried it on mine.