I have been running my vehicle on B50 since Oct. No apparent fuel line leaks yet. Got one tank of B100 in my tank last fall before the refinery (Refuel Biodiesel, Atlanta, GA) switched to B50(50% ULSD) for the winter. My car loves it and there are negligible differences in performance & fuel economy. My question is, what color should my exhaust be under load? Before I switched, the only smoke I ever saw was during aggressive acceleration or going up steeper hills. It was, of course, the normal black color. Same story today, but it is white in color. I get no smoke upon start up, or at idle when cold or at operating temp. It does not appear to be blue in color. The exhaust does not smell of oil (I'll admit it would be tough to smell anything over the smell of Bio exhaust). The engine appears to have used no oil in 2k since last oil change. I have revved the engine up to about 3500 rpm once it was up to operating temp and I get a puff of white exhaust. Is this normal? Should I be concerned? I may go back to a tank or 2 of #2. Good idea? Thanks.

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