RennKit-Dave

My track car. AC working great until last session here at Road America. Then no AC (yes I use it to stay cool on false grid) and starting to see lots of foam from vents. Could the two be related? What shall I check to diagnose AC system?

Carlo_Carrera

I think you have the infamous blend door problem in your HVAC system. Check out this link.

https://rennlist.com/forums/996-foru...-issue-14.html

Carlo_Carrera

RennKit-Dave

Ok that will tackle the foam issue. But doesn’t seem to be a connection to the no AC issue. Will hook up Durametric and see what it says.

Carlo_Carrera

I think the missing foam on the blend door will effect the functioning of the AC as well as the heat.

ram_g

Yes, but the lack of foam should lead to weak AC rather than no AC - the blend door still works, it’s just a bit porous now! I suspect there is something else going on as well.

griffiths

Toss a set of gauges on the system and read the static pressure (before you turn on the AC) and the running pressures.

If you do not have gauges, check if the outer ac compressor clutch hub is engaged and turning with the pulley.
If it is, a normal running system will have a cold return line.

The foam issue? The evap box has to come our and disassembled. Fix the foam, replace the evap core while you are at it, toss in a new drier, evac charge and test.

Lazurus

3M heat resistant tape can be used in lieu of replacing the foam and you can cover the holes in the blend door also. It makes no difference for the functionality of the blend door flap.

I suppose the holes in the door are to allow outside air to enter. But it works either way. Replacing the heater core is good advice since you're there.

Scrh1

Solod chanve your resistor packs on your cooling fans on the rads up front are bad. DIY on here be online to solder in new ones cheap or buy the fans and resistors and rep,ace your rads at same time if they haven’t been done yet. They aren’t cheap so depends on time / diy / budget. I opened to get new fan packs as it was less hassle and I don’t want to revisit this work in 6 or 9 months when my soldering fails. You are removing the front bumper to fox this regardless. Good luck

ram_g

This is the “correct” way to do this but expensive as the whole dash has to come out. Many people have reported success with the method referenced in posts #2 and #3 above, and I’ve also seen references to going in through the console after removing the radio and AC controller.

The foam in my ‘03 has largely blown out already but I still have reasonable AC performance so I haven’t attempted any of this in my car yet. If (when) I do, I’ll try one of the shortcut methods first before disassembling the dash.

griffiths

miss post, meant for Renne-Dave, but your comments always help.

Scrh1

The no ac issue is likely due to the fans and resistor packs on your radiators having gone bad or maybe just the resistors.

mcwop23

i have the foam issue but my AC is ice cold so I won't address it unless something changes, it has no effect on anything other than sometimes blowing a little out here and there on occasion

leftlane

I paid a local indy $70 to rectify my foam issue with a method he guarantees for life - no more foam in the last 3 years and my AC still blows ice cold.

RennKit-Dave

I wonder exactly what magic he performed?