How To Replace A/C Evaporator Coil in 2000 Astro

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I am merely driving my van
I am merely driving my van
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Joined: Thu Mar 04, 2010 8:50 am

How To Replace A/C Evaporator Coil in 2000 Astro

Post by dadmobile »

I've gotten lots of great info from this forum and figured I'd give something back. After the AC evaporator coil sprang a leak in my 2000 RWD conversion, I scoured the web for how-tos on the coil R&R. After seeing a post from somebody saying they'd followed the Haynes instructions and still couldn't get the coil out, I knew it would be a struggle. So here's my procedure:

Remove and replace AC Evaporator Coil on 2000 Astro:

(my leak was a slow one, on the coil discharge tube, inside the big fitting that screws into the drier. I don't have rear AC on my van but all the fittings are there since its the "upfitter" model astro, so the difference would be a bigger freon charge if you have rear AC, and an additional return line tied in somewhere.)

Gather up:
new evap coil w/orifice tube (my new coil came with an orifice, they're $3, but check the box to make sure),

new accumulator/drier (the thing that looks like a 24 oz beer can attached to the coil),

PAG-150 AC system oil (8 oz bottle is plenty, I got the kind with fluorescent dye in it just in case my system ever sprang another leak),

32 oz 134a freon (3 cans is 36 oz),

Also, depending on how your heater core hoses look, you may want to get a set of those to replace while you're in there.

My fleet mechanic buddy says to replace the drier and orifice any time you break the system open, but you can technically reuse them if unavailable.

If there is any freon left, have the AC system discharged by someone who has a recovery machine.

Run the engine for a minute with the climate control set to heater-hot to open the heater core flow valve.

Drain the coolant.

Remove the air filter/intake/MAF sensor and the upper fan shroud and the front grille. Remove the coolant reservoir/washer fluid tank assly. Don't let that washer pump come out or you lose all the fluid.

Spray all the AC fittings with penetrant - coil to drier, drier to line, coil/orifice to line/valve, valve to rear AC line, and lastly, line to condenser - the fitting you can now see in front of the radiator because you removed the grille.

Remove the accumulator/drier. Be careful when turning the fittings that they aren't stuck to the lines and the lines twist - be patient. If the coil-to-drier connection is frozen (mine was) just cut the coil tube coming out of the black plastic - you're scrapping both those parts anyway. Save the drier for now, though, or at least take off the old O-rings and pour out any oil inside into a cup and keep that. Cover the open line fitting with tape or a baggie and rubberband to keep out junk.

Undo the the other fitting connected to the bottom evap coil tube, the fitting that connects the rear AC line, and the fitting in front of the radiator. The whole service valve/rear AC valve/condenser "spider" tube assembly will come out. Set aside and keep clean and dry. Cover the open lines in the van with more bags or tape.

Disconnect the heater core hoses from the heater core. DO NOT TWIST them or you may break the core and then you've got a whole climate control system to replace - Haynes says to cut them free but on my 2000 they came off with some gentle coercion. Bend them out of the way, unless you're replacing them, then disconnect the other ends and remove.

Unbolt the heater core control valve and what I think is the rear heat control valve from the side of the evap coil enclosure. The core valve is bolted on top and bolted to a bracket on the bottom - remove the bracket from the evap coil enclosure.

Inside the passenger footwell, remove the two bolts (10mm?).

The black plastic evap coil enclosure clamshell is held together by a bunch of little screws, going in both directions. You have to get them all out to free the driver's side of the clamshell. There is one of the screws deep down on the passenger side bottom, right up against the wheel well. It took me a while to get out since only a tiny crescent wrench can fit there, turning 45 degrees at a go. Don't put this screw back in unless you like getting frustrated - you won't miss it. I think at this point I also removed the blower fan outer housing and fan control resistor block - May not be totally necessary but it can't hurt.

You should now be able to remove the drivers side of the enclosure - push the heater hoses and valves to the side and wiggle it out.

Still can't see the evap coil? That's because it's in another black plastic enclosure you need to open. This one can stay in the vehicle, just get it open enough so you can get the coil out. Pull the coil, minding the gaskets of the inner clamshell - I reused mine but RTV will work if they fall apart.

The bottom tube of the evap coil contains the old orifice tube - pull it out and pay attention to the direction its installed. Install the new orifice into the new coil in the same direction, after wiping the orifice gasket with some clean PAG-150 oil.

Vacuum out all the leaves you can see inside the enclosure, replace the gaskets, and install the new coil. Reassemble the inner clamshell and reinstall the outer one.

Your new drier and coil should come with new O rings of varying sizes. As you reassemble the system, replace as many as you can with new and wipe each one with a little oil. Reinstall the spider tube assembly.

You need to add PAG-150 oil to the system by pouring it into the new drier. Measure (eyeball) the amount of oil you poured out of the old drier, and replace it with fresh oil in the new drier, adding 1oz for the new coil and 2 oz for the new drier. I hardly got any out of my old drier so I added 4 oz total. Install the new drier.

Reinstall everything else you took out. In addition to the heater hoses, this is a good time to replace your air filter and front light bulbs, and to do a radiator flush.

Evacuate the AC system with a gauge set and vacuum pump. Shut off the pump and watch the gauge for a few minutes - if you lose the vacuum you pulled on the system, you've got a leak somewhere (good luck). Start the engine and AC, and recharge the system with freon.

Now you should be blowing cold.

Any additional pointers are welcome.
2000 Astro RWD Archer conversion
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Re: How To Replace A/C Evaporator Coil in 2000 Astro

Post by LiftedAWDAstro »

Nice write up! =D> Where are the pics though? :poke: :D
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy
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