2002; 3.0; 260,000 miles; USA

I have a condition in which warm air comes out of the driver's side front facing vents when the AC is on and the blower motor on high. Tested so far:

-all flaps and actuators working and glued

-separated front joint of HVAC box behind radio, visually inspected temperature flap (working, no visible cracks)

-felt with hand inside evaporator chamber: 80% ice cold air, 20% hot. Despite much effort cannot "feel" the direction or source of the hot air (obviously the heater core, ultimately, but can't tell where the ingress is)

-inserted borescope into chambers through same opening as well as a couple cautious test holes in the side of the box. No evidence of a rupture in the temp door, which can be viewed entity, or in front visible chamber where evaporator is.

Here's the most interesting part. When the blower motor is on low, one or two "bars" on the climate display, the hot air does not penetrate and AC is ice cold from all vents. As the blower force is dialed up, the air becomes warmer through the driver vents, as that's where the stream of hot air ends up flowing. Closing these vents helps cool the car down, but that hot air still redirects somewhat to the others.

My best guess is that there is some sort of breach between the lower chamber of the heater core and the evaporator/cold chamber above it (if I understand the geography of our HVAC box). If so, it's not visible with my scope and could be under the evaporator itself. This might be found by removing the heater core and exploring that chamber. I'm on the verge of just buying a whole replacement HVAC box and tearing the whole dash out.

I travel in deserts where the temp well is over 100F, so the lack of cooling in the cabin is simply not something I can live with (it would be a non issue in other climates, just leave on low!). Any advice appreciated, I want to make sure there isn't something I've missed. Has anyone had a similar issue? Ever pulled the dash and HVAC box? Thanks in advance.

 

There have been cases in other X Types where those symptoms were caused by an undercharge of refrigerant. As the reduced charge passes across the evaporator (from right to left), it runs out of chilling effect before it's reached the other side. The lower the fan speed, the lower the rate of evaporation and so the further across the evap the refrigerant gets before giving up and allowing a warmer airstream through on the driver's side. Higher fan speed - vice versa.

 

Astromorg,
Thank you, this is helpful news, and explains how this works beyond what I understood.

I had ruled this out originally. I noticed this problem right after replacing the entire AC system except evaporator, and doing a vacuum pull and recharge in my driveway. There were many steps involved and I was convinced I had undercharged it or had a leak. I was also measuring pressures at high elevation and calculating to compensate, so I was sure I messed something up. So, I went to a shop that specialized in AC repairs and asked them if they could find a leak or if I was undercharged on refrigerant. An hour later I'm told the refrigerant is fine, the blend door is broken and would be perhaps thousands to fix. So I left and here we area year later with me having tried everything (else) imaginable! It now seems likely that they never checked the refrigerant levels, they just pressure tested for leaks then ran the AC and diagnosed the blend door based on the symptoms we all could see.

Seeing as this is very easy to test, I will post again once I've added refrigerant. I'm now at sea level fwiw. If it's this easy I'll be thrilled.

 

A six dollar can of refrigerant fixed it. I'm thrilled. Thanks for taking the time out to answer today, you resolved a year of mystery/hot misery for me astro.

 

Thanks Astromorg! Your explanation makes perfect sense . My '07 developed the exact same symptoms as Kevin, and like Kevin I had been messing around with the refrigerant. I have a new AC manifold gauge set, a few cans of 134, and I'm waiting for a new FCM to arrive before I attempt to recharge the system.

Cheers from (100-degrees today) Fabulous Las Vegas!

 

I used this one as it has some added ingredients and benefits =

https://www.jaguarforums.com/forum/x...3/#post1684682

I particularly like how it handles impurities already in the system.

 

please let me know how you accessed the blend door actuator
and how things workd out

i have cooler on the left, warmer on the right vents

 

https://www.xtype.uk/x-files/43/how-...ng-blend-flaps

https://www.jaguarforums.com/forum/x...s-cold-127794/