My A/C does not stay charged for more that 2 days and has been diagnosed as the a/c evporator by a pro. So can someone help/tell me how to replace it. I do not want to pay to have it done.

 

I did it on a '99 van, I would think a truck would be a bit easier, unless the dash is very different. You may want to get a subscription to Alldata on the internet, it's pretty cheap and gives usable diagrams and steps. In fact this is the very thing I got it for.

Drain coolant, remove the heater hoses from the evap housing.

Remove the thermal expansion valve and filter/drier from the heater/ac evaporator. Seal the lines, put tape over the drier (or better yet, have that replaced, too. Whichever -- leave the tape on the new/old one until just before install), '

Disconnect the the thermometer and other connections from the housing.

The cable that controls the airflow ("blend-air door") comes through the firewall behind the glove compartment on the van -- not sure about a truck. I removed the glove compartment. You need to disconnect the cable end at the top of the housing (outside) by removing the pivot bolt. Then, back inside, under the dash, the air-door link connects to a lever. This lever must be disengaged. The Alldata / or other manual pictures were very helpful here.

The housing is connected to the firewall by nuts that are accessed at the engine side and at least one inside look close.

The evap housing is also connected to the blower motor housing -- remove those screws.

You should be able to slide it forward. Now, on the van -- it was cramped and I had to actually remove part of the front cap, and radiator supports to slide it forward. Don't take any shortcuts on removing what ever you need to be able to slide it forward because too much pressure on it and you could crack the housing (this needs to be intact for air-tightness).

Now, you just remove all the screws to take top off. You may need to re-use the black rubber insulation that seals the core. Remove the thermomter/sensor and re-insert new one core and re-assemble.

Be careful that the air-mix door swings freely inside the housing.

At this point, you should add two ounces of liquid PAG oil to the unit before re-assembly. I forgot and just used a PAG oil charge can along with the refrigerant charging.

After reassembly, I took it to a shop to pull the vacuum, but I brought it back to put the refrigerant in. If you do this, you need to short the low-pressure cut-off switch with a paper-clip to get the compressor to pull the r134 in. Check under the hood for the quantity to refill.

Hope this helps,
Lee