300SDL Oil Pressure Light

Part of my commute consists of driving about 15 miles on a winding, two-lane mountain road. Within a couple of minutes of leaving the flatlands and getting onto this
road, my oil pressure light comes on and stays on.
The first time it happened, I naturally pulled right over and turned off the engine. After waiting a few minutes, I started the engine again and the light stayed off. So I drove home.
The oil pressure gauge offers no corroboration; it hits the upper peg as soon as I start the engine, even on the initial start following an oil change when I *know* the oil takes ~7 seconds to make its way through the new filter, and stays there for the duration.
There are no secondary indications like low oil level or rising temperature, so I suspect it's either a short cir- cuit or the result of oil sloshing around in the pan.
Has anybody else seen this behavior?
Geoff
'87 300SDL 260K '91 300D 2.5 (RIP)
--
"I mentally relieve in my pants." -- Jae-Im Woo


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this may well be a silly question by me, but, did you check the oil level on your dipstick.... it's mechanical and works well...
cheers, guenter

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Yes. I check the oil twice a week.
Also, as I mentioned, I'd just changed the oil (although this had been going on for quite some time beforehand). I know I put the proper amount of oil into the engine.
I was interrupted in the middle of composing my original post, and a detail I forgot to include was that recently, the light has been coming on while I'm driving on the (level) freeway. It comes on dimly at first, then gradually brightens. Oddly, this only happens in the afternoon, when I'm on my way home from work; never in the morning, going in the opposite direction on the same freeway.
Geoff
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writes:

Geoff, That is the compass feature. Obviously you need to always drive toward magnetic North :)
The light in my old SD was for oil level. The sensor was mounted on the drivers side of the oil pan (or was that on my old SE?).
I can think of two possible explanations. 1) the sensor is going bad and is affected by heat (warmer in the afternoon?) or 2) there is some intermittant clogging in the oil galleries that is preventing the oil from returning to the pan quickly enough.

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The difference between the gauge and the light is the light indicates low oil *level* and the gauge indicated oil *pressure* at or near the crankcase bearings.
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It is most likely low oil level.
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What weight (SAE) is in the motor??
If < 20 - XX use greater SAE weight in this old engine.
Otherwise, if this is an electric gauge, I'd check the dash board gauge's ground connection.
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