I was involved in a discussion with a fellow that doesn't have access to work on his car. He claims that he can change oil by pumping in out of his dipstick rather than draining it from below. I told him I thought that this wouldn't be as good since he would have to be leaving some residual oil and dirt behind.

He actually claimed that this is what some dealers do. Is this true?

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1991 300D 172,000 (totaled)
1998 E300 Turbodiesel 82,500