[curtis73]

Don't incite a panic. He could have blown a head gasket. That's happened to me a couple times before. For the most part, today's engines have a redline determined by powerband, not capability. That is to say, Its just that his engine doesn't make any more power above 6500 so there is no use to rev it that high... not that it will explode above 6500.

7000 should be safe for that engine, but its possible that it exposed a weakness; like a head gasket that was about to blow. Tell him that if its white steamy smoke, he's burning coolant and he either blew a head gasket, cracked a head, or cracked the block (the blocks were a weak-ish point on Saturns) If its blue-ish smoke then its oil and he may have cracked a ring, lost a valve stem seal, or scored a bore from too much piston speed. Of those three options, the cracked ring is typically the more probable. The bores get a ridge of wear at the top and excessive RPMs can let things temporarily stretch letting the piston up just .0001 more inch allowing the rings to contact the ridge and crack them.