Quote:
Originally Posted by GregMN
You live is AZ where the relative humidity is 14%, not FL where it is 98%.
|
But what if I decide to visit Florida?
I took apart the automatic climate control heater case from my car. It came apart without too much effort--mostly removing clips and being careful to not break the fragile plastic. I wanted to see how feasible it would be to cut the second set of drains from it and graft them onto the manual heater case either plastic welding or bonding them using methyl ethyl ketone. I also wanted to see the condition of the heater core and evaporator so I could pick out the best parts from the three heater cases I have.
As I expected, the evaporator was very dirty, mostly from debris that got sucked in through the rust holes in the firewall partition at the blower motor opening. I'll have to do some hole patching--perhaps I'll try welding in new metal (I have almost no welding experience).
The heater cases have been full of unpleasant surprises. One was discovering that the heater core in the manual heater cases is much smaller than the one the automatic climate control cars have. The surface area of the manual heater core is 13X5", or 65inē. The surface area of each core in the automatic heater core is 7X6" or 42inē--making 84inē total, which is 19inē more surface area than the manual heater core. One thing I've enjoyed about my car is the massive amount of heat the heater would put out back when the heater worked and I lived in a cold climate. I definitely don't want to downsize the heater core!
Unfortunately, there isn't enough room to install the large version heater core in the manual climate control case, because the flaps which control how much air pressure from the blower motor is allowed to pass through the heater core, are in the way. With the manual heat system, the heater valve is either fully closed or fully opened, so the amount of cabin heat is regulated by these flaps.
Another disappointment I encountered was finding that the heater cases made before January 1979 (which is both of the manual cases I have) really aren't intended to be taken apart. The parts that did come off were glued with a mastic filler, and the rest seemed to be plastic welded together. So, like the heating and air conditioning service manual states, if the evaporator leaks, you cannot remove it without damaging the case, and the whole case assembly must be replaced. So stupid! So, most W116s have this type of case, which means that if the average owner's evaporator leaks, they can write off ever being able to use their air conditioning again.
So, I found myself being stuck with downsizing to a smaller heater core in order to use the manual case and having to use the broken case that's set up for air conditioning and already has an evaporator in it, while hoping it doesn't leak and then crying when it does--or cutting apart the uncracked case, installing the evaporator, and then somehow putting it back together. Either option didn't sound good to me.
I came up with a compromise; I plan on using the automatic climate control case from my car so I can use my large heater core and can remove and replace the evaporator if it ever leaks in the future. I'll also have the four drains. I inspected the cases that had only two drains--yikes! Condensation dripping off the evaporator goes through these skinny little rubber tubes (which were both clogged and torn) which route into heater core section--certainly not adequate!
I can't use the front part of the manual case on my automatic case because it doesn't have the grooves to hold the butyl sealing strips (remember the early cases just used mastic filler). So, I will need to remove the cable bracket from the manual case and rivet it onto the automatic case. I will also need to remove the vacuum pods on top of the automatic case and fill in the holes. It appears that I can use the lower part of the manual case with the control levers on mine--but I will need to cut away the plastic partition in the center. There are also plastic sheets over the flaps which would make the already seemingly impossible job of replacing the flap foam completely unfeasible unless those are cut off as well. Or--I could use the lower part from my case if I remove the vacuum pod (yes, they hid one in there, totally inaccessible!), drill holes for the control lever mounting and tap in the splined nuts.
Because I'll be using the automatic case and large heater core, that means the heat regulating flaps from the manual case can't be used. I decided this is fine because it's a lot of clunky linkage, more flaps needing new foam, and I drove my car for years with the heater valve either fully opened or closed with no complaints other than having to open the hood each time. Now that I'll actually have a blower that can operate at multiple speeds, I think this will be adequate. I'd rather lose some fine-tuning of the heat temperature than lose heating capacity.
I had thought about making the heater valve cable-actuated instead of by vacuum, but this would be a bit of a hassle to integrate into the system without making it look like a hack job. I also don't think that the slider levers are stout enough to handle that much resistance from a cable that long, especially if it gets gummed up. So, I am just going to leave it as intended with the heat lever on each side opening and closing the heater valve by vacuum. It will be a bit redundant having a heat lever on each side, but oh well. It's no different than the way it was intended other than the flaps won't be adjustable separately between the left and right sides.