Plan to replace AC evaporator: Need help w/ parts list

Madhelpermonkey · Post by **Madhelpermonkey** » 03 Jul 2012, 09:52

Hey there. Seeking counsel again on a big job.
I want to do the evap core. I would like some guidance on what I should take care of while the car is gutted...
I want to assemble ALL the parts I may ever need or want before I start.
FYI I already got a boneyard cabin filter holder for $5 and have installed it and a filter when I did the radiator last month.

My specific questions are as follows:

What brand of evaporator?
Do heater core if no problems currently exist??
What about air flap seals and controls?
How do correctly identify the or rings I need for the A/C core, accumulator etc?
What brand Accumulator?
Are there known or expected pitfalls? Something that frequently/always breaks that i should have a part ready for?

I have read one of the detailed photo write ups on the project done by chuckcintron by the one by ichrolle people.umass.edu/gfeldman/volvo_850_evap/index.htmlIs not available anymore and the one by songzunhuang www.matthewsvolvosite.com/forums/viewtopic.php?f=1&t=18166 cant be found . kodak gallery has changed to Shutterfly and I cant find nothing on there. Are there other write ups to be found that I can read for added information?

As always i am grateful for the forum, the site, and those who share the knowledge. You make me look smarted than I am on many occasions.

Post by **JRL** » 03 Jul 2012, 11:25

What brand of evaporator?

OEM Volvo or Behr (which is OEM)

Do heater core if no problems currently exist??

It would be a good idea if it's more than 10 years old!

What about air flap seals and controls?

If they work, don't worry about it

How do correctly identify the or rings I need for the A/C core, accumulator etc?

You need four O rings, two for the Evap and two for the heater core, that's it!

What brand Accumulator?

Whatever you want, they all work

Are there known or expected pitfalls? Something that frequently/always breaks that i should have a part ready for?

Just be REAL careful with the cheap plastic dash clips, poor design, not strong and if you break those and you're totally fracked!

Madhelpermonkey · Post by **Madhelpermonkey** » 03 Jul 2012, 11:54

Thank you sir. Why Behr or Volvo on the Evap Core? Is it a fit issue or parts quality?

Also I thought rot from a lack of cabin air filter was a major culprit in the failure of these on many 850's. Was there another cause?

Madhelpermonkey · Post by **Madhelpermonkey** » 03 Jul 2012, 12:35

Cant find a Behr evap core what about Nissens..they did good with the radiator?

Post by **rspi** » 04 Jul 2012, 05:36

LOL, I'd like to start off by saying, if it's not loosing the coolant at a rate of a can per 2 months, leave it. It's just not worth the work. They claim that R134 or whatever it is, is not harmful to the ozone so $8 per 2 months is nothing compared to the cost and work you are about to face.

I used Nissens and all went smooth except I always try to put the flapper door plastic piece on backwards and break it, every time. I keep forgetting that it swivels and spins around. The part will come WITHOUT the "O" rings that I got from Volvo. When you get them from Volvo, make sure they give you the Evaporator "O" rings because they are so conditioned on giving out the heater core "O" rings that they may just do it again. Caused me a head ache.

There is a good write-up here on VolvoForums. I keep meaning to add photo's to it but keep forgetting. I used the pics from Kodac but you say they're gone, not sure why.
http://volvoforums.com/forum/volvo-850- ... ions-1696/

I actually have a Nissens core sitting in my storage. I also have the "O" rings if you want to purchase them from me, you can PM me. Might save you a few bucks. I purchased 2 but decided against doing the second car after doing the first. LOL I'm currently using about 3 cans per year. When I look at the cost of doing the job, which ended up being about $180, I would have to buy 20 cans of the freon to just offset the cost. That's like 7 years which I doubt I'll have the car another 7 years. I do realize that the leak, once started would only get worse but what the heck, 7 years of cost and 12 solid hours of work, just doesn't add up. I'd have to be going through at least a can a month do to the job again.

Post by **JRL** » 04 Jul 2012, 10:38

No experience with aftermarket evaporators, why take a chance on such a large job?
Nissans may be fine, I just don't know
Try World Pac for the Behr.

Why does it fail, it's a poor design, the rust and crack at the seams
Lack of a cabin filter surely doesn't help but it's definitely not the root cause, they ALL fail from 1994 to 2000 (and up to 04 C70s), it's just the way they're designed.
The P2s don't fail

Madhelpermonkey · Post by **Madhelpermonkey** » 04 Jul 2012, 21:42

Thanks so much Great insight.

For the record its been leaking for 4+ years and getting worse. R34a went from $4/can to $10-$15/can since then and is going higher. I am at 1 can per week having charged fully on Sunday and today it was short cycling again. 100+ degree days doesnt help either.

I am game for the job but want to be prepared and take care of those thing on a 169,000 mile 16 year old car that ought to be replaced the one time i have the dash out.

Evap and Heater cores are being done. What do you think about heater hoses. they have never been done to my knowledge and I just replace the 2 radiator and 2 reservoir hoses and the radiator and thermostat. Are ther any air door seals that can/should be done or do i just look once apart?

Appreciate you valuable time and advice,

Chris

Will advice on this thread as i get closer and what parts i buy and once I start I may post my suicidal rants if there are issues.

Chris

Post by **Fish stick88** » 04 Jul 2012, 22:15

Trust me, There WILL be issues, Most not to be alarmed by but need to be taken care of, You need to get an A/C disconnect kit, You should be able to get them from your local auto parts store, You'll need your system pumped down(vacuumed out), prior to pulling it apart. At least 10oz of JB weld, or a similiar plastic welding material, I found this to be invaluable as the brittle plastics at 18 years old, break easier than potato chips. If you don't already have a cabin air filter, and retainer, plan on getting that and doing it at the same time. Hopefully your fan is ok, and you should have a decent set of Metric sockets, (extensions too) and torx bits. (not the cheap ones, the ones that hook onto wrenches, or 1/8 nut drivers)

Plan on this taking you 2 times as long as you expected. I planned a Friday night - saturday night build, and it ended up taking me all the way til monday morning about 3am, working about 14 hours a day on it. Excluding about 8 well deserved break hours on saturday.

you didnt mention, and I dont know, Does your system have Ecc or Mcc? with manual control, you should also inspect the door flap connectors, cant think of actual names right now, and, my interior of my MCC unit, the rubber on the flaps, had actually degraded enough to become sticky. so, i had to use some goo-gone, wire brush, and had to scrape that part off. It definitely helped the pressure i had to use on the knobs. Mine is working great now.

Let me know if you have any more questions I did this about a month or so ago, and its still working great, and doesnt make any noise from plastics.

AJ

Madhelpermonkey · Post by **Madhelpermonkey** » 05 Jul 2012, 05:13

Wow thanks AJ.

I have the A/C line disconnect tools. I just installed the cabin air filter holder and filter., Fan and Resistor are fine. I have a fine set of tools including multiple variety of tors bits and drivers. I have manual controls.

The JB Weld is a great idea. I had planned to have the system evacuated and then vacuum tested and refilled after the work by a local shop since I don't have that equipment.

Chris

Post by **Fish stick88** » 05 Jul 2012, 08:06

Manual climate control or Automatic? Does it have the degree of heat in red bars, or in degrees? That will help solve any flap problems, getting in there can be quite a pain. Make sure you find a few good websites for help too... These are what helped me, and not to spam you with information but they all are pretty well.

Climate unit illustration, Volvo 850, knobs, switches, circuit board, panel

Specifications for the AC, and Heating system

Download the Volvo 850 AC and Heating system PDF

Dash Sketch
Here

Damper Box, assembly Sketch
Here

How to remove the problematic Damper control arm
Here

Floor Shutter Fix
Floor Shutter Fix

Better look on the removal of the floor dampers...
...If youre having this problem
Here

THIS IS THE ULITMATE LINK. ENTIRE DASH REMOVAL.
This Is The Ulitmate Link. Entire Dash Removal

Like I said sorry for the overload, but i prepared about 3-4 months for this, and it went rather well for me. The more reading, and specific understanding of this area of your car, the better.

Also, i didn't mention, but "felt tape" is quite nice to have as well, because you will need to put stuff back in, this helps to reduce noise, and sound (especially Squeaks)

I got a roll thats 1" by 75' and i used about half of it. Most parts stores dont have it, because its more of a specialty Item.

Let me know if you have further questions