Morris Minor Owners Club

Hi,
We finally got the pickup back together on Friday night and made it to the National Rally yesterday. 198 mile round trip of A roads in the heat. The new springs and poly bushes completely transformed the drive.

We had a recurring problem with the oil pressure light flickering every time we stopped at idle. A few rpm more and it goes out. The wiring and connection are all good. 11 months ago we had the same problem and a new switch fixed it. I really don’t want to be replacing oil switches every year or 1000 miles.

Has anyone fitted a 20psi switch like this from Peter May Engineering?

https://www.petermayengineering.com/pro ... ht-switch/

Or the Minispares adjustable 20 - 120psi version?

https://www.minispares.com/hps1-oil-swi ... -20-120psi

I checked the oil level when we got home and it hadn’t dropped at all. I couldn’t see any signs of leaks anywhere.

Sounds like the pressure switch contacts...
I hate to mention it, but I was also at the Rally yesterday and noticed at least a couple of the Traders with collections of used original Oil Pressure and Brake Light switches.
With hindsight, I'm wondering if I should have brought one or two, 'just in case'.

OP may have just got unlucky with the switch replacement, I don't know. I fitted an OPS from ESM about three years ago and no problems with it so far.....I guess that's about 9,000 - 10,000 miles.

OP says: A few rpm more and it goes out.

Fitting a higher pressure warning light would not solve anything - if, indeed, the oil pressure is low.

How low is the tick-over? It may not be set quite high enough.

The oil pressure may be low, or adequate with a warning light wrongly indicating.

Does this occur with a cold engine? If not, the oil viscosity may be a contributing factor.

There may be leakage through the PRV, which would show up more with hot oil.

Changing the switch is a relatively cheap try, but what if the fault is still there? I would always fit an oil pressure gauge in parallel to the warning light (which, incidentally, we always used to refer to it as the idiot light - it tells you nothing until it is usually too late!).

Other possible faults could be oil pump or crankshaft bearing wear. Have these been considered?