Well, its winter here in Indiana and of all the problems I expected to have with my Cabby no heat wasn;t one of them.
So I started out figuring out how the heater system worked. First the fan needed new brushes. Then I wondered about the vacuum lines so I traced those and found some in the wrong places. Fixed that. Then I checked the heater valve. Works fine. So I changed the thermostat. Old one was working but new one is hotter. So now it's time to tackle the heater box.
If you read the diagrams in your Bentley you'll notice the pics don't really show the core's location in the black "turd" as it's affectionately referred to. So I tried to remove the thing and found it to be a major beetch.
First you remove the kneebar cover (easy) then the knee bar itself (forst remove the engine CPU on the passenger side and then the fuse box from the drivers side) See pic one. Then remove the dashboard (Ok I stopped at this point and looked for alternatives).
So I punted and cut a hole to ease/yank the core out sideways. See pic 2.
This was complicated by the end cover that goes over the hoses or I should say "according to the Bentley" goes over the hoses cause the hoses really go thru the cover. Crap!! I'll deal with that later.
Ok pull out the core and check for leaks (none) and flow (some). Let's look inside the friggin black box and see how it works since no one at Bentley bothered to .
Air enters the car thru the air inlet (catchy name huh?) and is moved by the fan to the backside of the box. It then passes thru the A/C core which would cool the air if it was working (a summer project) that air either goes out the A/C outlets on each side of the dash or thru the heater core which is next in line. Then it's heated (supposedly) and exits either thru the defroster vents or the heater vents (at floor level) depending on your dash panel settings. There is a vacuum servo that switches between defrost and heater on the drivers side of the box. There's a servo on the right top of the box that opens for center vent operations. There is one more servo on the air inlet in the engine compartment rain tray. This allows fresh air in at all times except in heater mode when it switches to recycle cabin air so you're heating the already warmed air for a quicker heating of the poor freezing driver.
pull the core out gently, but you'll probably have to yank pretty hard.
The last pic shows the holes that go THRU the cover. Modify this so it will go over the hoses without needing to remove the hoses from the core.
This daigram shows the flow of air thru the system. Blue show cold air, red shows hot. Not show are the flaps for the heater and defroster sections. Face it if you have hot air who cares where the heck it comes out?
Modified by Moljinar at 8:17 AM 12-21-2003