Was this perhaps on Saturday? I had almost exactly the same thing
happen to me... I had just done the oil change, and this time used
Valvoline 20/50. When driving on Saturday, all of a sudden I couldn't
maintain oil pressure (I unfortunately have the idiot light, not the
gauge). I checked the oil level - good... I checked to ensure oil was
getting to the top of the engine - yes. The really odd thing was if I
turned the car off for a few minutes, then restarted I had decent
pressure, but then slowly but surely the light would come on dim at
first, but getting stronger. I talked with a few people and they had an
interesting suggestion - perhaps the new oil had more detergent and as
such had free'd some of the sludge in my engine and that was plugging
the oil channel where the sensor is. Anyways, I had the car towed home
- oil lights are never a good thing. Yesterday, I decided to check it
out and couldn't replicate the problem. Anyways, I'm going to change my
oil and see what happens...
From: email@example.com [mailto:firstname.lastname@example.org]
Subject: crazy oil pressure
On the way home from Carlisle...we (Gail and I)
noticed the oil pressure was a bit low. Warm, it
was max'ing out 40 psi. And yet at an idle, it never
really went below 20psi.
I was beginning to believe maybe my oil pump had taken
a nose dive. So today, I put in a fresh supply of
Mobil 1 15/50. Wow! Now considering the old 20/50
Castrol had less than 150 miles on it.... why would
the Mobil 1 push my pressure right back up to the
80-90psi range cold?
Right out of the bottle, the M.1. 'swishes' around as if
it's thinner than what came out of the crankcase.