Air conditioning/Heating-did a search

[LLCoolLS]

I'm wondering if anyone can help shed some light on my situation. I've done a tireless search and couldn't find a thread that describes just what is happening to my AC.

2002 LS8

I found that when running my AC, there is always a little bit of heat passing through. I even took a therm probe (Turkey thermometer) and measured different temps in various locations on the air vent.



AC compressor engages just fine
refrigerant levels are good.
I already replaced my DCCV and the fuse is not blown
I swapped the DATC and it behaves just the same
I ran the self diagnostics and no codes are thrown with either DATC

I've been dealing with this for some time now and have resorted to just not driving the car on the very hot days (up to 44 C or 111 F in Toronto with the Humidex)

I've just discovered something today though. When I change my air mix to dash/floor vents, I get cool air (55F) in all the dash vents and hot air on the floor (100F) but only the driver floor vents. The passenger floor vents are still cool around 65F, but not quite what it should be. I've resorted to just taping over the driver floor vents to shut them, but I'd like to get to the bottom of this.

I'd rather buy a new car than disassemble the dash, not knowing exactly what I'm looking for.

This has been happening for so long now in fact, that I noticed that there is always full heat blowing through. On warmer winter days, the cabin gets so hot I end up driving with the windows open. I just can't rely on my climate control anymore.

Any ideas?

 

[joegr]

What results do you get from the self diagnostics?

There are only two heater cores, one for the driver's side and one for the passenger side. There's no way for it to put a different temperature out of the floor vents than the dash vents on the same side.

 

[LLCoolLS]

I thought so too, but I swear I'm not crazy. The self diagnostics yielded no codes. When I have it set to dash vents only, the temperatures are mixed as I illustrated. I am starting to suspect that my heat mixture door is not doing what it is supposed to do and that's why I'm getting various temperatures in various locations.

The passenger side seems to always be just fine, so maybe the driver side heat mixture door is the problem? What I don't get is that I'm not getting any codes when I run the self diagnostic.

 

[chocolat1701]

sounds weird but could it be the blend door?

 

[scjmc]

IIRC the LS does not have a blend door. Temperature is regulated by DCCV and auxilliry water pump that flows coolant through the heater cores as needed. You might be getting coolant flow in one or more cores when you shouldn't. Do you get all cold air when the engine is cold?

 

[LLCoolLS]

Yes, I do. While the engine is cold, all the air is cold. But I sort of dismissed that because even if you have it set to heat on the coldest day, you would still have all cold air while the engine is still cold because the coolant passing through the core hasn't warmed yet.

I think my auxiliary pump is fine because when the weather is cold, I still get sufficient heat at idle.

Despite having already swapped my DCCV with a genuine ford part, do you think that is still the problem? By the way, the problem existed before changing the DCCV, and remained unchanged after installing the new one.

 

[scjmc]

I don't know enough about it to tell you. All I can say is that it sounds like the heater cores are getting coolant flow when they shouldn't. The AC is having to cool the air and then overcome the trip through the heater core/s. Your temps coming out of the vents should be much cooler overall. I never measured the LS, but my 71 Mustang manages less than 5 degrees F at the center vents on a 90 degree day. I had a 93 Jeep Grand Cherokee that put out 12 degrees at the center vents. I imagine that when you get it figured out the AC will be much colder overall.

 

[LLCoolLS]

So, if the LS does not have a blend door, then that would mean that my driver heater core is getting coolant flow when it shouldn't. That would point me toward the DCCV that I had already replaced. But I still don't get how it can separate the heat from the cold, blowing only hot air to the driver side floor...SMH...

 

[joegr]

The LS does not have air temperature blend doors.