why is my oil pressure warning light on?

[otter]

<sigh>

Last summer, I took my Spider (2L turbo) out one weekend morning in preparation for a trip to Indiana. Oil pressure warning light goes on, I freak out a little bit. I am convinced I am hearing ticka-ticka from the rod bearings (my other old car is in the middle of getting a light rebuild because the rod bearings started getting noisy after 20k, so I've heard it before.) Pull over, stop, check level - full. Why is it on? Who knows? Get back! I start it up again and drive back to garage as quickly as possible, shut it off, don't drive it for the rest of the season because I never get around to it (bike rides keep winning...) Earlier this spring, I start it up and listen to it. No light, don't think I hear rod bearings after all. Last weekend I recharge the battery and start it up again. No oil pressure warning, still sounds OK. Take it for a drive, everything OK. Earlier today I go to give it its annual oil change. Finish oil change, start up....oil pressure warning light glaring red at me. Schwah?

Did I do something to the sender wiring or whatever without realizing it when I replaced the filter? <checks> - nope. I am not convinced that the engine actually has low oil pressure, but obviously if it does and I test it by keeping it running, I am going to find out by killing the engine. Or else if it is fine I am going to sweat off a pound or so of stress finding out.

Quickest way to find out whether oil pressure actually OK? I could hook up a mechanical gauge but that's a lot of work just for a diagnostic. Not sure how to test sender, so I better dig out the manuals, I suppose. But it seemed worth asking y'all, too.

David Pertuz
Chicago

[djape1977]

just open oil filler cap while the engine is running, if there's a lot of oil sloshing around camshaft and little droplets spraying all over the engine bay than you're probably ok.
camboxes are on top of the engine and if they're full of oil, than there's plenty of it and most likely at decent pressure.
if there's oil in cambox, check wiring first.
if wiring is ok, find a mechanical oil pressure gauge and hook it up instead of oil pressure warning light sender unit, or just replace the sender, it's the same unit as on many newer cars and cheap, i currently run one from 2001 alfa romeo 156.

if you really have a low oil pressure problem, first try just replacing the oil filter. i've seen several filters of sub standard quality (chinese s****) which have actually restricted oil flow.

take a dipstick to your nose, does the oil smell like petrol?

[otter]

Thanks, that's the kind of quick first-order test I was trying to think of. Filter is good quality, a NAPA unit and same as the one I replaced.

David

[131]

Not uncommon for the internal spline on the oil pump drive gear to strip, I had one go in mine a few months ago. Fortunately I had a spare in the shed. http://www.autoricambi.us/product/LU6-4 ... --1979-85/
If problem is intermittent it's probably the sender.

[otter]

Stopped by on my way home from work - removed oil cap, started car. Nothing much coming out - oh, dear. Shut off, figure what the hell, let me remove the oil filter (that was messy), reconsider, just tighten it back. Feeling gloomy, start car again...no oil light. So inclined to suspect electrical issue but I'll have to just bite the bullet and drive it tomorrow morning as planned.