Oil Pressure Problem?

Oil Pressure Problem?

Author
Discussion

GreenV8S

30,152 posts

283 months

Tuesday 22nd June 2004
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The oil pressure is controlled very crudely by the oil pressure relief valve, but it is normal for the pressure to drop off at low rpm. There are several factors which will exagerate this though.

The preserpentine engines have a lower capacity oil pump which will drop off pressure more at lower revs.

The hotter the oil gets the thinner it will be and the quicker the oil pressure will drop off at low revs.

The oil will get hotter when the oil level is lower, so a reduced oil pressure when hot is a warning to check the oil level.

If you're using standard Mobil1 it is thinner than ideal and the 4T/Motorsport versions will give a higher oil pressure.

In any case the oil pressure will drop gradually as the engine gets older, you may even find the low oil warning light flickering at tickover with a hot engine if the engine is tired, not a problem as long as the pressure picks up again as soon as the revs increase.

peter miller

196 posts

251 months

Tuesday 22nd June 2004
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Many years ago,I used to have an old 1973 Rover 3500s,
The oil pressure light started to flicker on when running hot on idle,and gradually it got worse until it had to be running at over 1500rpm for it to go out.
Being a young apprentice with no money to spare, I decided that the cheapest remedy was the only option, so I took the dash off and wired the oil pressure warning light directly to the alternator light. It fixed the problem straight away,and cost me nothing.
I kept the car for a year or so, and then sold it to a mate who used it for a few more years until the floor rotted away, and it wouldnt pass the mot. He scrapped it, but the engine was still running as good as new....