Topic

The oil pressure warning light has illuminated twice the last two days. First time yesterday when I came home after a ten minutes drive and shut off the engine for a shot while. When I started it again the warning light continued being red. I turned off the engine and started it again and there was no problem. Today the warning light came on as I drove it after less than ten minutes. I shut off the engine and turned it on again and the problem was gone for the rest of the trip. What to do?
Is it the oil pump or a sensor problem? I am travelling to England from Denmark next week so the problem needs to be fixed in a hurry
I have checked the oil level of course

First and foremost, check the oil level.
Once you have established that there is the required amount of oil in the sump, you should do an oil pressure test.
This will require you to buy, beg, borrow, bludge, hire or steal a diagnostic oil pressure test gauge:

On a warmed up engine, you remove the oil pressure switch from the engine and replace it with the hose of the gauge. (and adapter if required)
Then start the engine, give the throttle a blip to make sure the oil is circulating, let the engine drop back to idle and take a reading from the gauge.

Idle oil pressure should be between 1.7 bar (24.6 psi) to 3.5 bar (50.7 psi)
The maximum oil pressure below 40˚C @ 6500 RPM is 7.0 bar (101.4 psi)
The oil pressure switch opens at 0.3 bar (4.3 psi ) to 0.5 bar (7.2 psi)

Once your satisfied that your engine is generating sufficient oil pressure, you can then safely assume the problem is the oil pressure switch itself and replace it.
Low oil pressure could indicate a whole lot of problems (none of them good) such as:
*Worn conrod and main bearings, possibly crankshaft journals too.
*Worn oil pump.
*Damage to or restrictions in oil pick up and tube.
* Too light a grade of oil used for the conditions.
* Insufficant oil in the sump, causing air to be picked up.
* Excessive oil in the sump, casuing the oil to become aerated.
* A blocked oil filter can also be the cause.

# 54 is the feller your looking for:

I would like to add to Cobber,s great explanation. one of our club members had an oil pick up problem on his 1998 MGF, the oil pump was rattling and cam followers clattering and oil light on!!! when the garage removed the sump plug NOTHING came out!! when sump was removed it was full of solid black sludge, so thick that it would not pour, it was so thick that the oil pump would not pick it up. It was felt that it was caused by mixing Fully synthetic, and semi synthetic oils together. sump was cleaned filter changed , engine flushed , filter changed again and refilled with Castrol Magnatec 10W40 oil and its now like a new engine! It is the original and has just turned 100,000 miles.

Had a garage to messure the oil pressure. It is spot on. So no worry. Will change the oil pressure switch.

had a new oil pressure switch put on and I have not seen the oil pressure warning light since. It was cooling water from the headgasket ( which has been repaired) that made the switch turn on the light.

Thanks for updating us! Good to know all is well now!