Blue smoke puffs @ start-up...

[Schrade]

When I start up the motor, I see blue in the exhaust. Seems like it's lasting about 10 - 12 seconds, then stops. Car has 37k.

On the road, I unloaded a few times at dusk just today, and didn't see much exhaust in the headlights behind me - maybe some Black / fuel.

I never noticed this startup oil before, except after the front was on the ramps for more than a few days. That I figured was from being '90 w/o valve stem seals (???). Pooled head oil was draining to #'s 7 + 8, and pulling through the burn?

Is it possible that OEM exhaust was absorbing some of this oil? (and it's always done it?) And only now, with headers + straight 3" tubes, it's showing more easily?



Ideas?

[Paul Workman]

Normal, methinks for a 90 especially - having no oil seals on the exhaust valves. And, even with seals, a certain amount of oil gets into the plenum and pools on top of the intake valves, ready to be sucked in and burned at start-up.

If as you say, it last for only the first few seconds, I wouldn't give it a second thought. Keep an eye on consumption, and realized these motors seem to use the top half of a quart, according to the dip stick, and slows after that, unless you're putting your foot in it a lot.

I've got a 90 with a valve job done less than 5000 miles ago, and new seals were installed on all the valves at that time. Still it puffs blue if it has been sitting a while (as does Ami's 91). I don't have my oil catch can installed yet. Maybe that will reduce the oil in the plenum, hopefully. But, a blue puff on initial start-up is nothing to obsess about!