Re: more on dead engine

[raf40@oes.amdahl.com (Richard Funnell)]

Dan,

>Just thinking out loud here...
>I called Mobil and they said it's pretty unlikely that the
>thinner oil caused this damage, since there is not much difference
>between a 5w30 and a 10w30 oil at running temperature.
>(Also, as I pointed out to them, if the car would smoke because of
>thinner oil, wouldn't that happen at startup when the oil is cold?)

Not necessarily, since the engine tolerances at low temperature will be closer.

>
>I did think of another possibility after chatting with John
>Malick - I added some oil to the car on Sun (the day it started
>running rough) and perhaps I overfilled it.  OK, so wouldn't the
>excess oil just burn off and things return to normal?

Substantial overfilling can cause serious damage.  If there is way too much
oil, it can contact the big ends of the conn rods and create pressure shock
waves in the oil.  There is also the possibility of the oil being sucked up
and swirling around the crankshaft, starving the engine.

>I can't see
>the third plug's tip breaking off because of that, and I can't
>see my oil level drop considerably because of that.

If the plug tip didn't fall off, it must have been hit by the piston, which
suggests something seriously wrong already.  Still can't figure this one.

>I
>did notice oil leakage around the manifold yesterday, when I was
>trying to figure out what was wrong, but couldn't see where it came
>from.  Would this be a sign of the overfilling perhaps?

I don't think this would be a sign of overfilling.
>
>Grasping at straws...
>
>| DAn |
>--
>Dan Simoes                                dans@ans.net
>ANS                             http://coimbra.ans.net/dans.html
>100 Clearbrook Road                     (914) 789-5378 (voice)
>Elmsford, NY 10523                      (914) 789-5310 (fax)

Richard Funnell,
San Jose, California
'83 urQ
'87 560 SL