Oil pressure light flickers at idle. Stuck at school. Help!

[Desaevious]

Hey guys I was on my way to school and 5 miles off my oil pressure light starts flickering at idle. When I'm driving I hear no knocks or anything, but the sewing machine that the M20 is sounds a hair louder than usual. Should I drive this sucker home on backroads or tow the car?

Backstory: this has happened before. On this same day last year... the first day of spring semester... I had this happen only the oil pressure light came on while driving. I heard a bad knock and the engine killed itself. Now, a year later with a different engine and a different oil pump I'm having this damn light laugh at my face. I'm using 5W30. I have good oil level. I have no leaks. All seals were properly replaced on this new M20 this past summer by a BMW step program graduate tech that works at the local BMW dealership.

And to FredK, Pat, and BenM, I do trust you gentleman and the advice you gave me via texts but I was wondering what else it could be other than oil. These good guys are saying to change out the oil to something heavier and to do a pressure test to have the shop figure out where to go. I'm just sitting in class being brain racked wondering what it could be.

Thanks...

[jlevie]

5w30 oil should only be used when the temperatures are in the teens and below. For less severe winter weather you should be using 10w40 and the rest of the year 20w50.

The oil pressure light flickering at idle isn't good, but it may not mean that the oil pressure is in fact low. You could have a bad oil pressure switch. Another possibility could be a plugged oil filter.

Add one or two bottles of STP to the oil. That will raise the viscosity and probably turn the light off. Then change the oil (use 10w40 dyno oil) & filter (I like the Mobil-1 filters) and temporarily replace the oil pressure switch with a gauge and see what the oil pressure is on a hot engine.

[FredK]

Thanks Jim, for adding your voice of experience!

Desaevious, you're looking for STP Oil Treatment in the blue bottle (at least that's what I think Jim is suggesting to boost oil viscosity).

[M-technik-3]

Weather has been cold last few days. If you have dino sludge in there let it come up to temp before moving as the oil pump will have a hard time pumping that oil.

10w-40 in a cheap Mobil variant is fine for the winter. Winter always makes things get tested at these extremes.

[Desaevious]

Changed over to 20w50 with a new filter. I'm getting up to temp and driving and NOT having the light flicker at idle like it had been happening. Another thing...this is only the second time I've changed the oil in the last 1000 miles after the engine sat in a garage for 3 years. It seems like I am fine but I will check the pressure using the method Jim gave. I will also just replace the switch since it is a couple of bucks and remains the only part of my the M20 I haven't changed in the last few months.

Thanks guys.

[Cabriolet]

after i did my last head change. i didn't full seat the oil return pipe, car had a rough idle and the oil light would flicker at idle, when warm. seated it correctly issue gone.

[Helltime]

The only time i've seen this issue is when the car over heated on the first drive home and the oil got over heated, then on my way to the autoparts store (after fixing the loose hose that cause it to over heat) to get oil change supplies the light flickered at idle only...after i changed the oil all was good.