ok got my heater core replaced today, didnt do the A/C evap because it had been done last year by previous owner, it is possible to replace the heater core without discharging the A/C system because the heater core will simply slide out of the top of the heater box (on my 97 1500 im only assuming 94-2001 1500,2500,3500are exactly the same since they all use the same core but im not 100% on that) anyways i took off the dash according to the very helpful guides/pics posted by davmelrach and koldkut...kudos to you guys for that (just search by author for it under a/c evap replacment)...wanted to share my experience i did this job solo and did it in 3 and 1/2 hours, all i needed was a #2 phillips and flat head screwdrivers, a metric ratchet set (mostly 9mm-13mm) and also you need a set of 10mm-15mm deep sockets. once the dash is loose and secured to the 'oh **** handles' and you remove the two inner bolts and 4 engine side bolts of the heater box you can slide it forward (minding the a/c condensorlines on the engine side careful now lol) but they have enough slack once youve brought it forward about 4 inches you can lift the 2heater coretubesup out of thier cradle built into theheater boxand then slide the whole thing up and out of the heater box, then of courseinstall is the opposite, it took me quite a bit to get the dash put back into place by myself so if you have a neighbor you can pawn some beer to for helpid suggest it, but all in all its an easy job and doesnt take 8 hours nor will you have to pay a mechanic $500+ for labor the second picture shows the temp. controllinkage (top of picture connected to the white colored arm)which you have to remove by lifting it straight up (dont forget to put it back on like i did after i got 1/2 the dash back together) and the third picture shows the clamp closest to the firewall which is a real b*&ch to get off because of the angle and limited space, i ended up using a magnetic elbow joint socket with a phillips bit to get it out....thats about it good luck if you have to do this job and dont worry its not as difficult as most people say..one more thing be mindful of the top of the dash as it will crack very easy even with justa slight amount of pressure.

 

i am just finishing up mine now, no i didnt really have to drain the free-on form the air conditioner but it was probably a good precaution, i have one question what is that white lever in your picts? im pretty sure mine didnt have that?

 

the white lever is the temp control it connects to that metal linkage line in the pics and when u slide the dial for hot or cold itmoves a 'rudder' to funnel the air to either the ac or heat side of the heater box, or both if u have the dial set for cool

 

i dont think i have that and i have air and heat in my truck is that normal?

 

well i dont exactly know seeing that you have a 2001 it could be a completley different setup, could even be an electronic arm inside the air box as opposed to a manual link......the 2001's dont use digital air controls do they?

 

some will probabily flame me, but how much do you think the dash weighed? (lol, if you get what im thinking)

 

well considering i didnt actually lift the whole dash i just kinda pivoted it because the driver side was resting on the steering column id say it was roughly 70-80 pounds if you lifted it completley out of the truck but thats with my glovebox and all my crap in it still attached so i suppose ive got about 10 pounds of crap in there alone lol

 

not so much heavy as it just is awkward

 

nice,im gonnatake my weight down to 3900 lbs next time i go to the track

 

What kind of replacement heater core did you use, and did it come with foam? When I attempted to replace mine a couple of weeks ago, the replacement heater core was aluminum with crimped on tubing that rotated on a collar. That did not look like a good design to me, so I returned it and am ordering a proper copper/brass heater core from Rock Auto.