Doesn't sound good to me. Between the acidity and abrasive metallic particles, it just doesn't seem like it'd work without damaging your engine. Not to mention the increased emissions and cancer possibility. I can't believe that you even generate enough WMO to make it worth it, unless you run a shop, in which case you should get the garage heater.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition