I noticed recently my '91 LS400 w/72k miles has emitted a small cloud of blue smoke on startup. A small amount, mostly from the left exhaust pipe (but some from the other side too). I recently changed the oil to Royal Purple 5-30. Doesn't happen every time, and not just after sitting overnight, can happen after only a few hours. Could it be sucking oil from the crankcase venilation system? Otherwise car runs fine. Smog test was excellent too.
any ideas?
Blue startup smoke is typically valve stem seals. Even with low miles, on a
12-year-old car, this sort of thing can happen, which seems to be more calendar-time-related, rather than miles-related. Unless bad, I'd just monitor and drive.If this problem coincided with the change of oil brand, I'd return to what you were using. There have been anecdotal reports that changes to oil brands late in a car's life can cause seal issues. I'm not a believer in gimmick oils like Royal Purple. If it was my car, I'd be using Mobil One synthetic.
- Mark
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