Oil Pressure Switch Intermittent

[juitz]

Hi everyone,

I recently noted the my oil pressure light is coming on. As soon as I start the engine from cold, the light goes off, but then it goes back on as the engine warms up. When I rev the engine, the light goes off as well? Doesn't make sense in as the oil would be easier to pump at high temps as it becomes less viscous and if there's blockages I'd assume the light would just stay on?

I think it's the original pressure switch and seemed to work OK, and I've checked the wiring and this also seems to be OK.

If I crank the engine with the switch removed I can see oil coming out from the port the switch is installed. I've not removed the tappet covers but have taken the cylinder head side covers - there are signs of oil on the o-rings, but it's not spilling out the holes when the engine is running.

I'll probably buy a new switch, change the oil and filter, clean the mesh at the same time as a starting point. But any advice on what else to consider?

[taysidedragon]

Oil pressure will reduce as the oil gets hotter and "thinner". It's worth checking the switch and the oil pump.
If they are not the problem you might have a bigger problem developing.

[K2-K6]

Good plan to change oil etc.

Filter comes before the pressure in galleries and switch ... it shouldn't be impaired, but can affect this area.

Oil, if its many short runs and rich (on choke etc) then dilution won't be helping you with pressure. Also the reason why compromised oil from dilution causes wear to bores, bearing etc.

Good baseline to change oil and then assess what the status is before further consideration. 

Smell the old oil vs new to give an idea if it's petrol-ee  and give you some level of confirmation if its significant.

[Bryanj]

On the 550 the switch is on the oil pump so after it is main gallery to filter.
I have seen bad primary chain wear on the gallery to filter but not yet one worn through

[SteveW]

My 550 had the same problem, new switch sorted it.

[deltarider]

My 550 had the same problem, new switch sorted it.

Usually it's just the switch. Sooner or later they all need replacement.