Tuesday, May 27, 2014

Fixed: Dodge Grand Caravan AC Evaporator Replacement

My dearest love has a 2002 Dodge Grand Caravan.  Much to our vigorous dismay the AC went out at the beginning of this month.  I filled it with R-134a (Refrigerant), but it all leaked back out.  Bad times.  So I took it to Firestone for a diagnostic and they found the leak.  The Front evaporator had failed.  This is the component that absorbs the heat from inside the car.  The unpleasant bit is that it is buried deep deep inside the dashboard and you have to disassemble a lot to get it apart.  The estimate we got was $1400, and I just couldn't spend that on a 12 year old van.

So I fixed it myself for $300.  This is a hard project.  It has lots of pieces to remove and keep track of.  When you have this completely apart, the only thing left on the passenger compartment firewall is some wiring, a plastic bracket, and the pedals.  I do not recommend this as a first-timer or novice project.  It is doable, just take your time and it will all work out. 

I would do this again if I had to.

Tools needed:
  • AC Gauge and Hose Set
  • Vacuum Pump 
    • One of my local AutoZone stores had this in its loan-a-tool program.  Sweet!
  • Metric Wrench set
  • 1/4" and 3/8" drive socket sets
  • Phillips and Torx Screwdrivers: #1, #2, T-15, T-20, and T-25
  • A flat thin prybar for removing trim
    • I used a beekeeper's tool called a hive tool for this.  It worked fantastic.
  • The factory service manual
    • The haynes book does not cover this
  • A sharp right-angle pick (awl) for pulling out the old O-Rings
  • Masking tape to block off the open hoses.
Optional Tools:
  • I used a UV "leak detector" flashlight to double check the Firestone guys.
    • Trust, but Verify.
  • I used a Ryobi Cordless driver and 3/8" drive adapter to speed disassembly.  
    • First time using this, loved it!
  • A Box fan.  (You'll see why.)

Procedure:
The procedure in the manual is straightforward, even if it is really long.
Remove 9,000 access panels
Disconnect a bunch of stuff
Drop the steering column
Pull the entire dash out
Remove the windshield wiper box that goes from one side of the car to the other
Recover the refrigerant
Drain the coolant
Disconnect the AC lines from the expansion valve
Disconnect the rubber lines from the heater core
Remove the five bolts that hold the HVAC box to the dash, (one in the passenger compartment) and 4 in the engine bay.
Pull the whole thing over to your workbench.
Pull the expansion valve
Remove a couple of dozen screws and open up the HVAC Box.
Remove, clean up, and replace the evaporator, foam wrapper, o-rings, and rubber hose covers.

Replace the o- rings on the expansion valve.
Put everything back together.

You "should" replace the gaskets that attach the HVAC housing to the firewall but I did not.  Instead I cut them very carefully on an angle at the parting line of the housing.  I probably could have avoided my condensate water leak issue if I had replaced these.

It books at 10-12 hours according to Firestone.  I hit some snags and it took me a bit longer, probably closer to 16 hours.

Snags:
My evaporator from O'Reilly Auto Parts didn't fit quite right.  I was able to carefully tweak the bends in the lines  make it work, but it was fidgety.  I don't blame the O for this, I think my part had been opened previously.

My van has two metal hard lines for the rear climate control heat.  One was really corroded and broke when I pulled on its mounting bracket.  I got another from pull-a-part.

I broke the passenger side power mirror trim when removing it, and replaced it with a pull-a-part part.  This is quadruply annoying because I figured out I didn't have to remove it at all.

The blue Low Side adapter for my Harbor Freight AC Gauge set failed.  It wouldn't let any gas flow through at all.  I replaced the O-ring, but it didn't help.  I ended up using one of the little 6" hose-with-gauge hoses that comes with an AC refill kit to fill it and measure the pressure.

When I finished the repair the condensation from the AC was leaking back into the car at highway speeds.  This got the passenger side carpet really wet.  The solution is to install a drain hose, part number 56000724AB, onto the evaporator drain.  My van didn't have this OEM and only the HVAC housing to firewall gasket was preventing the leak, so I had to get one from pull-a-part.  Of the two dozen Dodge and Chrysler vans at the junkyard I found this part only on about a third of them.


Tips:
At some point in the dashboard removal process your neighbor may saunter over and look at you like you've lost your mind.  If that happens, tell them you have to find your lucky penny and give them the Jack-Nicholson-from-the-movie-The-Shining-look.  Priceless

Clean out the front of the car and the glovebox before starting.

Move both seats all the way back before disconnecting the battery.

There are almost 100 screws, nuts, and bolts in this project and most of them are different.  Egg-carton and label them or you'll regret it.  

Yes, the windshield wipers and the housing do have to come off.  It's not hard, 6 torx screws, 2 big 15mm nuts on the wiper arms, one electrical connector, 4 small 10 mm nuts on the housing, and 4 13mm bolts holding it on.  There is a small disconnect for the windshield washer flexible rubber line on the passenger side of the car behind the air cleaner.  There are also two big 1.5" drain hoses, one on each side of the engine bay.  Don't knock off and lose the rubber elbows for them.

When the book says to disconnect the Floor Distribution duct, do it.  The HVAC housing won't come off if it is in place and it is a serious PITA to disconnect after you get the dash out and sitting on the front seats.

You do NOT have to remove the power mirrors, just disconnect the electrical connector on the top of the dash.

All of the screws under the dash are Phillips #2 except the hood latch.  Those 2 are Torx.

It's easier to get the driver side lower steering cover off if you disconnect the parking brake rod first.



There are three driver-side under-dash electrical connectors that have to be disconnected.  One is the huge yellow-and-gray bolt together connector.  The other two are the bottom two of the five vertical square shaped connectors.  These two are not keyed differently and you can get them mixed up.  Mark one of them with tape and save some drama.

Gingerly place the dash on the front seats.  You can bend the radio and climate control knobs if you aren't careful.

The Evaporator is inside the thing called the HVAC Housing.

The 4 HVAC Housing mounting bolts are in the engine bay on the firewall.  One is above the passenger side strut mount in that little slightly-taller-than-your-finger gap, one is to the right and below the expansion valve, one is next to the heater core hoses, and is behind the bolt-on bracket that supports the metal hard lines for the rear HVAC heater.  Be gentle with that last one, my hard lines were corroded and broke when I pulled it.

You should replace the AC Drier when you open the system.  I did not, because I knew that my system had been empty (exposed to atmospheric humidity) for less than 48 hours.  To get as much moisture out as possible I pulled a vacuum for 30 minutes, purged the system with dry air, and pulled a vacuum for another 30 minutes.

Take a picture of the Evaporator before removing it so you can get the foam wrapper and hose covers right on the new one.

You have to add 2 oz. of AC oil to replace what is in the old Evaporator.  You can save a few bucks by buying the unpressurized container of oil and pouring it into the evaporator instead of buying the little 1 ounce cans of oil in the pressurized container.

If your van has one, replace the cabin air filter while the HVAC housing is apart.  



Vacuum, refill, and leak test the AC system before you put the dash back together.

Replace the o-rings on the lines in the engine bay and the lines from the evaporator.  Do you really want to save $0.25 and risk having to do this job again? :D

You drain a lot of the cooling system as part of this.  Why not go ahead and replace the rest of the coolant too?

If your heater hoses are going bad, go ahead and replace them too.  You'll have really easy access to them when the wiper box is out of the car.

Both pieces of weatherstripping on the wiper box cover were loose and falling off on my van.  I glued them back in place with 3M adhesive.  (Wear gloves, this stuff is hard to get off your hands.)


Take lots of pictures.

Stuff to Buy:
48 ounces of Refrigerant
2 ounces of PAG oil
An evaporator
A universal set of AC O-Rings, the green ones
A set of gauges and hoses
A vacuum pump (or rent)
The brass adapter that lets you hook a small can of Refrigerant to a set of gauges
1 Gallon of concentrated coolant, or 2 gallons of pre-mixed coolant.
Optional: Replacement gaskets for the Housing-to-firewall connections
Optional: Condensate Drain Hose
Optional: Cabin Air filter
Optional: AC Drier

3 comments:

TNT Crusader said...

This certainly sounds like a great money saving project, but 16 hours...wow!

Thanks for the detailed info.

Greg

Anonymous said...

$1,100 savings and 16 hrs, $68.75 / hour, don't know anyone that makes that much. Most people would have to work 3 to 4 times the hours to get that much.

Elizabeth Greene said...

I don't make that much, certainly. ;) Ask again in a few years.

I probably would do this project again if it needed it. It was a huge amount of work, but the cost savings were awesome. Lucky for me it's still blowing nice and cold! Yeah!