Typical symptom.
A/C blowing warm, add a 12oz can of R134a and it works fine for a couple of days, then blows warm again.
Found some leakage at the service port valves and changed both valve cores with minimal effect.
Checked the Receiver/Dryer, located to the left of the radiator under the battery. The insulation was soaked with dye and there was dye all over the place on the lower frame members.
It turns out that at least through the '98 model year, Ford wrapped the R/D in foam insulation. The foam absorbs moisture (duh!) and keeps the case of the R/D wet causing it to rust out. The isulation was eliminated around the '99 model year.
Replaced the R/D (remove the battery for clearance) with a Motorcraft part from Advance Auto - cost ~$75.
Blowin' ice cubes again!
When I got the old one out I used a wrench and tap-tapped the surface rust in couple of places - found two areas of perforation.
Before starting the procedure, make sure you have the usual A/C tools and the proper spring-lock coupling tools (Black and White), some PAG oil and new O-rings.
AL
