I just replaced my leaking WW pump O-rings. Here are my answers to your questions:
1. I now have pockets of air in the heating coil, does this matter? Will it be flushed out automatically?
A: It is my understanding the air gets pumped out by the natural flow of the coolant.
2. How do I test operation of the heating coil (in the summer)?
A: Drive the car normally, when it occurs to you, open the hood and carefully touch the pipes. They should be hot since the engine coolant circulates continuously through the WW tank.
3. There's a 2 inch piece of clear tubing, split to allow slipping it over the heating tube. Anybody know where on the tube it's supposed to go? It fell off during removal and doesn't seem to have an obvious purpose.
A: I don't recall this piece or where it goes.
4. I stirred up some flaky light brown impurities off the side of the tank while working on it. They seem to be deposits from the water. Will they pump through the system ok or should I try to suck them out of the reservoir?
A: You definitely want to remove this scale. It can clog your washer nozzles. When I did my repair I took out the tank and used a coffee pot de-scaler to get rid of it all. Took a couple of times but it worked well on both the tank and the curled tube within the tank.
5. Why are there little paint splashes on the hose clamps for (see photo -- white where hose meets washer fluid reservoir heating tube, and red where hose meets coolant reservoir)? Any significance of the different colors?
A: The paint marks are: 1) left over from the original manufacturing of the car 2) are placed there by a true factory trained tech who replaced the lines and used his/her own paint. The philosophy behind this is to visually quickly identify which connections were completed and checked. In the effort required to paint them, one is also saying the job is good and has been double-checked.
Hope all of these answers help. (Four out of five)
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)