W110 W111 W112 Sedan, BENZ AID - COMMON QUESTIONS AND ANSWERS

Can anyone shed light on how to properly test a 617 Turbo Diesel Transmission Vacuum Shifting Valve? (See MercedesSource item BCM-COMTVSA for reference.) I have a used one that looks in good shape but is untested - so of course I want to check if it is actually in good shape before throwing it in. Thanks!

First of all, it's not December 31, 1969, but instead is April 9, 2008. I have a 1990 300TE that had a heater hose break, and the dumb fool poured cold water into the radiator bottle. Now I have oil in the water (though no water in the oil!). Advance Auto sells this bottle of green fluid that GUARANTEES to fix leaks in head gaskets, cracked blocks, valve cover gaskets, etc. that is added to water. The big hitch is that the car must be able to idle for 50 minutes while the stuff does it's thing. One thing I found out; a cracked block is not conducive to idling more than a couple of minutes - much less 50 minutes (no wonder it's guaranteed to work if you follow the directions to the letter).

I recently replaced the dash instrument assembly in my 1985 300DT and now I have a few spare parts, like the old still functioning tach. What is involved in installing a tach on my 1982 240D. Is it an electrical or a mechanical pickup?

Looking for insight before I pull the trigger on a gallon of MP. I'm in the process of having my lifelong Santa Barbara CA 1980 240D repainted and the body guy tells me the bottom of the doors under the seal are rusted pretty bad. Ugh. I specifically bought a CA car to avoid this!