Ok guys, the heater core in my ‘99 LE 4x4 w/277k mi’s, has sprung a leak. I’ve flipped through the FSM, the interwebs, and YT and yet find nothing that covers this. Can anyone share some tricks and tips to getting this done?

The replacement procedure is written up in my Haynes Repair Manual. It looks like a very tough job, even after removing the entire dashboard, floor console and many wiring connections, as the following instructions indicate.

mdmellott wrote: ↑

Wed Aug 02, 2023 8:39 am

The replacement procedure is written up in my Haynes Repair Manual. It looks like a very tough job, even after removing the entire dashboard, floor console and many wiring connections, as the following instructions indicate.

Thanks for taking the time to take those pics and post them! I have no clue why the FSM wouldn’t have it.

Whoa, that is quite the job. I’m planning on a 5spd swap here in a week or so, I think I’ll do this all at once.
I’ve had the console out many times due to a wet moldy carpet and insulation and then replacing the carpet all together, so I think I’ll be able to perform this, no problem.
Thanks again for the reply and info!

Echoing the above. It's a lot of work. The entire dash has to come out. I've done the job on a similar era Frontier (00), but I was already pulling the dash for a massive clean-up effort.

You'll also want to confirm that the inlet/outlet tubes are ok because you'll need to remove them from your core and re-use them. I'm not sure what was used on yours, but if they're plastic tubes like they were on my Frontier, they can become brittle, so you may want to try disconnecting the hoses in the engine bay in advance to confirm if their condition. If they're aluminum, you'll be in better shape. Either way, be mindful of them...I don't think they're available from Nissan or aftermarket.

Cut holes in firewall and put your own aftermarket heater core strapped under dash w/ small fan ??? Anybody ?

I mean the car's been " partying like it's 1999 " for some years .........right ??

macgiver wrote: ↑

Thu Aug 10, 2023 8:54 pm

Cut holes in firewall and put your own aftermarket heater core strapped under dash w/ small fan ??? Anybody ?

I mean the car's been " partying like it's 1999 " for some years .........right ??

That's a good idea imo.

Hawairish wrote: ↑

Thu Aug 10, 2023 2:42 pm

Echoing the above. It's a lot of work. The entire dash has to come out. I've done the job on a similar era Frontier (00), but I was already pulling the dash for a massive clean-up effort.

You'll also want to confirm that the inlet/outlet tubes are ok because you'll need to remove them from your core and re-use them. I'm not sure what was used on yours, but if they're plastic tubes like they were on my Frontier, they can become brittle, so you may want to try disconnecting the hoses in the engine bay in advance to confirm if their condition. If they're aluminum, you'll be in better shape. Either way, be mindful of them...I don't think they're available from Nissan or aftermarket.

Yes it is, but I gotta get it done. I was wondering about those tubes as well, because all the cores I've seen are just the core and no tubes. The tubes on my Pathy are aluminum, so as long as theres no corrosion, I should be ok. Ill make sure to be very careful when removing the hoses, the core, and the tubes from the core.

I appreciate the response.

I hear ya.

As far as dash removal goes, it's not terribly difficult, but you'll literally be pulling everything so it's a lot of small things. Radio, climate controls cluster, trim, pass air bag, disconnecting practically everything electrical (def disconnect the battery first). When I was doing my Frontier, it also meant disconnecting the steering column from the dash frame and suspending it a little from the frame, just to be able to clear the dash over the steering column (fortunately, didn't have to remove the steering wheel or column in its entirety).

Also, make sure you really get underneath with a flashlight and check for any hidden fasteners. I accidentally left one in at the corners and ripped off two little tabs. Inconsequential in the end, but still. This is also a good time to pull the vent tubes and clean them out. I even went as far as pulling the dash frame and painting it, since it had a lot of surface rust.

Oh yeah, and I think there's also an o-ring between the core and tubes. The screws holding the tubes suck, so beware.

Well I’m finally getting to replacing the heater core, I drain the coolant and it’s milky A grey/greenish color. Now Im seeing where my 2mpgs went. Damnit. Now I don’t even want to bother with the 5spd and electric fan conversion.

Yikes! A greyish color is a blown head gasket. Sorry to hear that.

All due respect ,
air up the tires , wash all the glass , spray ' tire-black ' , roll it to the curb , survey says SELL....SELL ? ?
Probly want to take one of THE FIRST OFFERS ? ya ?
Somethi'n about shiny wheels and spotless glass .............will put it OVER the TOP , don't want it SITT"N now ?

p.s. L'est it be SITT' N AND SZHITT' N ..........................don't save the kitten

You're just full of high quality suggestions.

Exactly , I'm not that high quality , just my suggestions are......