View Full Version : replacing heater core (?)- w/ AC

02-17-2009, 03:55 PM
Hi- have a 97- D90 SW w/ AC.
Heater core leaks, and the shop manual told me to remove the under dash A/C evaporator, draining all freon, etc. Sounds kind of severe.
Anyone change a core and can give helpful hints? Don't mind modding the heater box if it'll help.
Thanks guys!
J.P. in VA Bch

02-17-2009, 05:04 PM
Having pulled the heater box on a truck with a 97 AC system, I can't understand why the manual would direct that except to access a couple bolts that might be under the unit in the footwell. I was able to reach up behind and hold them while a helper undid the nuts in the engine compartment. These were the fasteners on the bottom of the heater box. The heater box does have to come out to replace the core even though it looks like it just drops in the top. You'll need to move that white box that 97's have just in front of the heater box IIRC - and it takes some twisting and finesse to get the heater box out. don't worry about trying to get the heater hoses to disconnect from the core, just reach in and snap off the plastic stubs coming out of the core. You probably want to replace the hoses anyway. Have a couple different thicknesses of self-adhesive weather stripping foam on hand to re-seal parts of the heater box.

02-17-2009, 05:54 PM
Cool-thanks. guess it was to add mechanic time.
I did however notice rust / paint bubbling at the bend where the vertical pannel meets the angled fwd piece on the interior above the a/c unit. Sucks cause it looks like I gotta drop somthing anyway.
Don't know how the rust got in there.

02-20-2009, 07:19 AM
You can buy uprated heater matrix over here from companies like Bearmach (http://www.bearmach.com/) but they are very expensive. You can buy air scoops that sit on the heater intake which force air down into the matrix giving a greater flow. This would be a cheaper alternative. When replacing the matrix make sure you have the right type. There are two and there is no ryme or reason for which one you will have. The pipes will either come out of the matrix horizontally, or they will come out and bend down. Check before buying.

03-11-2009, 04:18 PM
Thanks guys! JimC-you saved me alot of aggrivation. Heater matrix is being delivered today, and I do have a intake scoop- keeps the pine needles out.
Q: Does the hood/bonnet really need to come off? Looks like there's enough room to work with.

03-11-2009, 05:05 PM
As drastic as it may sound, removing your RF wing will make life a whole lot easier. That only takes about 30 minutes, and once removed, it's all right there in your face.