I found a drip of coolant coming from my heater box today after refilling my coolant. Are there any rubber hoses in there that could possibly be loose or am I pretty much guaranteed a bad heater core? If so, how bad is it to fix that?

 

1. It's a bad heater core. The hoses are outside.
2. It's ugly. Full dashboard removal. Schedule a weekend.

 

Bad news...

If you look at the firewall where the hoses come off your engine and connect to the firewall... the hose clamps might be loose... you'd see some drips on the engine side of the firewall as well...

Although, if not, it's probably the heater core. If your windshield is fogging, definitely.

You need a stubby Philips screwdriver. A regular and small ratchet. A 13 mil. Socket. A 15 mil. Socket. A few extensions. A small 13 mil? Wrench. A screw gun helps. You need quick disconnects for the AC lines. A bungee cord, about 2 feet long to hold back the dash when it's free.

Two things... DON'T adjust your steering column when you unbolt it. ( you'll never get it back straight.)
And watch some videos where they only fully detach the passenger side of the dash and swing it out. Much easier.

 

If you bypass the heater core you can still drive it. Hella easy and cheap.

Getting to the nut on the firewall, directly behind the engine is the hardest part. The rest just takes time. You gotta pull the center console.

If you're dependent on this for work, bypass the core, and do the job in stages.

Take out the center console one evening. Disconnect the AC and undo the nuts in the engine bay another evening. That way, you can pull the airbag and rest of the dash, pull the box, change the parts, and have it drive able in an evening.

Advice... take lots of cell picts as you do it so you remember where stuff goes.

The hardest part, other than that nut behind the engine is lining up the box for reinstallation when you put it back in. I left the nut behind the engine off when done just cause its such a PITA.

 

I also used a roll of masking tape and marked the dash parts in the order I took the off. So I could reverse it when reassembling. Radio on. Beer helps.

 

Thanks guys. For now, I have the temp control turned to cold, but hopefully over Christmas break I can get it done. I have had zero fogging on the windshield except for really wet days. Maybe I can get by with an electric heater for a while until I have some real time to tackle this job. Ugh.

 

As stated its a pain. I once had to change my heater core so I did a dash swap too since I had everything apart. Mark all your connections as I didn't. When I put my dash back in, I had a couple plugs unplugged so I had to pull it back out

 

I just did it. Not that bad. Follow the FSM and you don't need to remove the dash.

I made notes in the manual. You will need a helper to get it back in.

 

Ugh, now I have the antifreeze smell inside... I'll definitely be bypassing it after class today. At least it's been a mild winter so far. It was -20F this time last year.

 

Is there any reason why I shouldn't just cap the lines? They each have another way for coolant to flow. I couldn't find all the right pieces at the store. Maybe I'll try another before I jump into this bandaid.

 

Yes, the heater core forms the bypass loop for when the thermostat is shut. Connect them together.

 

So this is what Rock Auto sent me... It doesn't look like anything I've seen in my Haynes book or online. Is this correct for a 1990 XJ with AC or do I need to give them a call tomorrow?

 

Looks about right to me.
Part number?

 

Vista Pro mod: 0398346

Everything I've found otherwise says I need the core with the long tubes. I even found a build on here of a '90 xj with the long tube version. I just got one from O'Reilly's so I'll have both on hand when I jump into this.

 

Here's the one I got from Napa.

http://www.napaonline.com/Catalog/Re...0038%202038004