My wife's 98 V-70 (sorry, I'm an old 240 guy and don't know the displacement, but its normally aspirated 5 cylinder), sends out a puff of white smoke on start up. I initially told her it was likely the head gasket. But, I can't find any evidence of any coolant going where it shouldn't. I've poked around the internet and have seen something about some sort of "oil sludge" buildup that may affect these engines (or perhaps any others for that matter) if the oil is not regularly changed (She had it for a few years before we met and so I suspect this may not have been done as regularly as it should have). Anyone know anything about this and whether this is the death knell for the motor, which is only about to tick over 120,000 miles?

The 2.3 liter engine is not much different than your 240. MIJ is right about oil sludge, which must be cleaned up. The flame trap is directly behind the throttle body. Pull it out and check the vacuum hose and throw that little screen thing in the garbage.
White smoke just at start up with a cold engine, sitting over night, and not the steam from the exhaust being warmed up, could be a leak in the head. The wrong kind of antifreeze will kill the aluminum white engines, causing pits to form in the engine block. Tell her to have a mechanic check it with a pressure test and get ready to trade it in.

Klaus
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(V♂LV♂s 1995 854T, 1998 V70R)

Oil will give blue or black smoke depending on quantity.
I still suspect some H2O in the system. If it only starts with a cold engine in the mornings then it's probably just condensation burning off and nothing to worry about.

At 120K's you should see to it that she has her PCV hoses and oil separator/trap serviced. Not only does ignoring this cause major oil leaks in the egnine, it could be one more reason for moisture to be trapped. Also, if she only drives it very short distances and doesn't let the engine warm to an optimal level, this could further cause this condtion.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.

Thanks for the advice folks. I was pretty careful about checking the flametrap on my old 240, but haven't paid nearly enough attention to her vehicle.