Morris Minor Owners Club

Yesterday evening when I started the car, the oil pressure warning light would not extinguish as it would normally within a couple of seconds. Having "ummed and ahhed" about why this was happening, I wondered whether it was because the car was parked on a steepish hill. So, I started again, and sure enough as soon as I hit level ground the light extinguished.

However, this morning, again I started the car (this time on level ground) and again the oil pressure warning light stayed brightly lit. It was only after some revving and about 10-15 seconds that it finally decided to dim and then go out.

I suppose it's noteworthy to mention that I did overfill the engine oil when I last topped it up.

Anyone got any ideas as to what might be causing this to happen?

Cheers,

Ryan

Is the oil level still right up ? This where an oil pressure gauge is worth it's weight in gold........ It's the only extra gauge worth having - and EVERY Minor should have one. Meantime - if you really think the oil pressure is low you must not run the engine - but there is a distinct possibility (assuming plenty oil in sump) that the switch may have failed/be sticking. Also possible (but unlikely) that the relief valve has stuck partly open. Try to beg/borrow/steal a gauge and fit it even temporarily to see whats actually happening. Try another switch if you have one - but don't run the engine until you are SURE you have decent pressure.

OK thank you for the advice.

Just to give some more background - the car is not losing oil, but the sump is quite overfilled - probably about an inch or so more than the 'MAX' mark on the dip stick. After the light extinguished last night, and I assumed all was well, I drove a 30 mile round trip and it behaved itself fine. It was just this morning that the light was slow to go out again, but it did go out. Otherwise, no strange noises or anything, everything seems absolutely normal.

Still worth getting it double checked you reckon?

As Roy said, you really need an oil pressure gauge to know what is going on, they were standard fitting in the Series MM. They are not expensive, certainly cheaper than an engine rebuild.

I think I might be mistaken. As I have a 1968 Minor 1000, is the orange warning light on the speedo in fact an oil filter warning light and not an oil pressure warning light? There is a wire which goes directly to the area of the filter. Forgive my ignorance, I'm learning every day, but what does this indicate if it stays lit?

There are two orange warning lights on the black speedo, the light on the right is the low pressure warning light and the light on the left is the blocked filter warning light which should never come on. Most filters manage quite happily without it and in fact I use the light in my Traveller for the trailer indicator warning light.
Also check that the correct lights are in the correct positions, ie the oil pressure and ignition lights.

Filter blocked light will NOT be on with engine not running - it will only come on when the engine starts -IF the filter is blocked. The low oil pressure light IS on when the engine is not running - and should go out immediately the engine starts. You need to get a gauge asap. Run the engine at your own risk! The overfill has nothing to do with it and will do no harm......