I’m looking at buying a 2003 scrambler 400 with 4WD. The seller made a comment it did overheat once, which concerns me, but I noticed the oil was full of small bubbles. It’s not milky as oil may get when water gets into the oil, but just a lot of small bubbles. He selling the atv for $1000, and it has a winch and snow plow. Sounds like it might be a good deal but only if the engine is ok. Does anyone know how I might check this out? Are the oil bubbles a real concern? Thank you