dmd on the 3l

[Bradness]

Hey Tom. Thanks for your explanation. It never crossed my mind about which phase of the 4 strokes the piston was in when failure resulted. I wondered if the pump possibly failed (the pickup screen was clean). I do have it although I've never opened it up to see-maybe I will now.

Like you, I NEVER use a 5W oil. I also try to use something with the 2 numbers as close as possible. Therefore, I avoid any oils like 5W-50 even if they are synthetics. My all around choice here is 10-30 synthetic year round and I use the block heater religiously.

 

[procyon]

DMD was/is only used on CAST cranks (cost save) - i.e. Freestyle and 500 and Montego.

Forged cranks do not get the DMD - from the factory.

Only reason for the DMD was Vehicle NVH due to the CAST crank. Nothing related to bearings, oil, or any other supposed urban legend.....

Absolutely incorrect. The following forged crankshaft engines come with a DMD from the factory:
1) 3.0L Mazda6
2) 3.0L Fusion/Milan/Zephyr
3) 3.0L Mondeo ST220
4) 2001+ 2.5L Mondeo
5) 2002+ 3.0L Mazda MPV

The usage of a cast crank on the Ford 500/Freestyle/Montego did indeed save cost. These vehicle have a lower rpm operating range and as such did not need a forged crankshaft. The cast crank can actually be a benefit in such cases because it is less stiff and will not be as "rough" as the stiffer forged crankshaft. You are correct that a DMD is used with these cast crank engines. However, it's a different DMD than you're used to (made for different poly-v belt.)