Miata Mailing List: July 1996, Message #145
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   From: Gus Harris 
Subject: low oil pressure
   Date: Tue, 2 Jul 1996 12:01:44 -0400

Kevin-

First....do you know what the "idle" oil pressure should be?  Mine runs
(according to gauge on car as best I can estimate it) somewhere between
12-15 idling (10W30 oil in 90plus temp).  I made a road trip this weekend
and since this oil pressure thing has been of some discussion here on the
list I noted where mine was at different RPMS/speeds too.  At cruise in 5th,
around 75 mile per hour, 3900 RPM (as I recall), my needle points "straight
up."  This according to the way the gauge is labeled seems to be about 40
psi.  My Miata is a 90 with 120,000 miles....and as I recall from day one
when I bought it (used with 48,000 miles) it maintained these same "idle and
cruise" readings exactly.  Certainly during warm-up the pressure is much,
much higher. 

I guess what I'm wondering is why you think the pressure at idle is "low."
>From my readings and those of others who have commented it really doesn't
seem to be.....

My old AH Sprite used to run about the same readings as I recall....with a
newly rebuilt engine (1275cc)!  

Sooooo....does anyone on the list have a definitive answer, according to
manufacturer's specs, or otherwise, what the pressures should be at idle and
cruise at particular speeds/rpms?  Until we know that I don't think anyone
can say whether oil pressure is REALLY low....unless of course it's running
well under 10 psi.

Where's the experts on this??????

Gus
90 MBlue