Machinos

I've been going through some of the old threads about it here and it sounds like there's a lot that can go wrong with the A/C box, so as long as I've got a leaking evaporator I'd like to fix everything that might need it at once.

My '03 is actually a gas truck, if that makes any difference. The A/C has been dead for at least a year, is it safe to assume I need a new dryer too? I haven't actively used it since it first started working poorly (presumably when it started to leak), but as far as I know it comes on with the defroster whether I push the little button or not.

I'm pretty sure something's wrong with whatever door is supposed to blow air on my feet, also, it seems to just mostly shut everything off except for the defrost vents. Then again, it hasn't worked since I bought the truck (60k or so miles), and I can't really think of any vehicle that had really GOOD heat/ac on the floor vent.


Another thing is that the factory fan motor ate itself awhile ago, and I replaced it with one off of eBay that fit fine and blows fine but is a bit noisier than the practically silent factory one. I was hoping it would just wear in with some use, but it hasn't yet, since about December. Anything I can do about that? It's annoying but definitely not bad enough that I'd care to pay $120+ over what I paid for this one for an OEM replacement.

Thanks!

Jeff in TD

Taking the dash out really isn't that bad. Just time consuming.

While you've got the HVAC case out I'd definately be looking into the various doors and replacing whatever needs replaced.

There was a write up a while back about putting the heater-treater metal doors in. They are designed to be put in w/o pulling everything out via cutting holes in the case, but the write up was about removing the HVAC case to install them. With the metal doors, hopefully you wouldn't have to worry about snapped off stop tabs, stripped couplers, and broken doors in the future.

Regarding the dryer, if it were mine I'd probably replace, but I'm no expert.

wiskeyVI

I don't recall who did the write up w/pics to get to the blend door,
but if you follow it it,s a piece of cake to get the dash out of the way.
Just watch for wires in the way when you bolt the steering columnback in place!!!!
It can cause big problems.

1-2-3

Any time you open the ac system, you should replace the dryer. Also add 1 ounce of oil per item replaced. 2 ounces if replacing the evap and dryer. Pout it in anywhere you can get it in. it will circulate and find its home

Sounds like your thinking that if you gotta open it up, then do everything, which is good thinking. While your at it, someone added some valves on their heater lines to stop flow of hot water. When you get in there, you'll see how hot water heats the air then the ac cools it back down. You can add three small ball valves outside the firewall, in an H pattern to create a manual bypass, which will take a tremendous heat load off of your ac and make it more effective. Just remember to occasionally open the valves to flush fresh coolant thru the heater core.

You will also need a supply of CLOSED CELL foam on hand to reseal the ac evap to the case. The factory stuff is glued to the sides and will tear up if you try to get it off. Don't use normal foam. It's usually open cell and will act as a sponge and hold moisture and mold and stink.

Totallyrad

Take a look at this thread. It should walk you through the R & R of the dash and the replacement of the blend door.

https://www.dieseltruckresource.com/...ght=blend+door

Jeff in TD

This is a good thread, too.

https://www.dieseltruckresource.com/....html?t=210483

Next time I do one, I'll go ahead and pull the steering column out entirely. Since you have it unbolted and all the wiring disconnected, may as well disconnect the shaft and have it completely out of the way.

kry226

Heater Treater R&R: https://www.dieseltruckresource.com/...t-t264513.html

Couple quick points of advice:
1. If you're going to go through the trouble of pulling the dash, do everything at once and do it right. Don't leave yourself open to needing to fix something again later because you used a cheaper part, etc. It's just too much work to do a substandard job. It's not hard though, just time consuming.
2. The dash is HEAVIER than you will expect. Having someone help you maneuver it will be very beneficial and you'll be less likely to tear something up.
3. Watch for the airbag harness connectors located on the tranny tunnel just behind the lower dash trim. These connectors are very fragile in my experience.

I am sure there are others and I'll post them as I remember. Good luck.

Machinos

Hey everyone, thanks for all the tips. I finally got my parts and got the dash removed, and am working on getting the HVAC box out.

Apparently I need some special tool to disconnect the AC lines from the accumulator and evaporator. My evaporator was used-and-tested-good off of eBay and just has those little red caps in the ends, but the accumulator is new and has some special-looking black plastic caps in the ends that I assume have to be taken out with a tool, same as the one on the truck.

If I were to just go to the parts store and ask for that, would they know what I mean? Any different sizes of tool, etc.?

Thanks!

kry226

These tools usually come in a universal kit, so you'll probably end up with a box full of tools except one that you'll never use. I would probably just run up to a shop and slip the guy a Jackson to disconnect your lines and reconnect when you're finished.

Of course, you could always buy the tools too. I am a tool gettin' kind of guy, but I think I would pass on this set of tools.

Machinos

I wish I'd thought of that before I took the dash all apart, ohwell. Hopefully some place rents them.

Another question is that I'm not actually sure that the AC lines are all that is holding the HVAC box to the firewall at this point - I undid every nut from the firewall that I could find, plus one attaching the box to the trans hump and two more attaching it to the firewall from the inside, along the top. Are there any others?

Jeff in TD

On the later trucks the other nut holding it in is hidden behind the coolant bottle.

The tools to disconnect those couplers are not expensive. Any auto parts place should be able to hook you up.

Machinos

It was $10 for a set of the hinged kind at O'Reilly, I did need two sizes... the side of the evaporator not attached to the accumulator was smaller. Still pretty hard to get off.

The HVAC box is definitely still attached somewhere and as far as I can tell it seems like it's right around the drain hole coming out of the firewall. There's not much leverage to get but I've been wiggling and pulling and it seems like that's the attachment point, however I don't know what to do about it... I can't really pry underneath it inside at the spot I want, and I'm afraid I'd break it if I did.

Also there was basically nothing left in the system, when I disconnected the first coupler it hissed slowly for a few seconds and that was it. Is there any possibility that something else could have gotten damaged by the lack of anything in the line? I'm planning on having the system recharged at work (they recharge the AC on motorcoaches all the time and will do it for the cost of the refrigerant), is there anything else that needs to go in, or just R134?

Jeff in TD

What year is your truck?

If it has the coolant tank on the dash, you have to pull that to find the last bolt.

The thing may be lightly stuck to the firewall insulation, but if you have everything unhooked it won't feel solid and will just pull right out.

Machinos

I did get the thing out, it turns out that the plastic clip that holds the heater hoses was mounted to a stud from the HVAC box, not just one on the firewall like I had thought. I had to work that loose to get at the nut.


I fixed the floor/defrost door by fashioning a clip-sort-of-thing out of sheet metal to fit tightly over the broken pieces of the door where the white drive piece inserts, then epoxied over that. Pretty sure if it does break again it'll be that white piece, but ohwell.

Two questions at this point:

1. Can I replace the O-rings on the AC line that attached directly to the evaporator? Do I need to?

2. How much refrigerant and oil do I ACTUALLY put in? With searching I've come up with different answers, and/or the factory charge amount is incorrect... also, do I have to buy a fancy manifold to check the exact pressures?