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Oil pressure

Posted: Thu Nov 18, 2021 9:17 pm
by Norm57
Evening all. I have been using R3 as my daily now for nearly three weeks 10 ml round trip.It has a few electrical issues and the central locking has packed up? What’s new!. My biggest concern is the oil pressure,when the oil temp gets up to around 90c and the car is idling the pressure drops nearly into the red.when I arrived home tonight the car would not idle at all and the needle was hovering around the red zone.please tell me it’s a sender fault and not the pump and are pumps still available if I need one?

Re: Oil pressure

Posted: Fri Nov 19, 2021 11:36 am
by dcwalker
Sounds like we need to get together again Norm...

Re the oil pressure; first off, remember that the gauges look pretty but aren't particularly accurate, so best taken as an indication of what's going on rather than gospel truth. Ultimately if the oil pressure drops too low the oil warning light should come on giving you just enough time to switch off...

When the oil is up to working temperature (which will be 90 degrees and upwards) when idling the oil pressure gauge should sit at the left hand end of the white segment. As long as it doesn't actually drop into the red segment, that's normal. If you were having idling problems then a rough, snatchy, half-hearted idle with the car nearly stalling will be playing havoc with the oil pressure anyway - if you think about it the "parked position" for the gauge needle is at the extreme left hand end when the engine is off, so if it's stuttering and nearly stalling you'd expect the needle to be heading that way.

On what you've said, there sounds to be an idling issue, but I wouldn't be worried about the oil pressure per se at this point.

Hope that helps a bit!

David

Re: Oil pressure

Posted: Sat Nov 20, 2021 11:53 am
by Jay-Kay-Em
Just to reiterate David above ^

At idle, with hot oil, the oil pressure light is boss. Until that starts flickering at idle, you have nothing to worry about.

(Assuming the oil pressure switch is working fine and comes on with the engine off, that is!)

Ignorance is bliss as they say, and if it was a non-oil gauge car, it wouldn't be a concern :lol:

Oil pressure test gauges are available on eBay from £20 (yeah, from China, sorry!) if it still concerns you - with a selection of adapters via threaded holes on the block. They used to say 10psi for every 1000rpm up to the oil pressure valve limit.

I have been a member of multiple owners clubs over the years and have witnessed oil pressure snobbery between members boasting how much their gauge reads. Modern engines excluded (with oil demands such as VVT or a timing chain tensioner), then I am a believer that merely "some" oil pressure at idle is good enough, assuming the oil pressure lamp is extinguished.

Re: Oil pressure

Posted: Sat Nov 20, 2021 2:12 pm
by dcwalker
Thanks Jay, as Alan480 has said, having the gauge just means one more thing to worry about!

By way of update, I've been over to Norm's this morning and we took R3 for a little trip. Hot idle the gauge is in the same place as mine, namely just to the right of the bottom of the white segment. On the 1.7, when hot, according to Haynes, 1000 rpm should be 2 bar, 3000 rpm 3.5 bar. On the basis that it's a 5 bar (70psi) gauge that doesn't have detailed calibration and is not exactly a fine tuned piece of engineering, those readings are what we has.

Norman will continue to monitor but I'm hoping he's a bit more reassured on this question now.

David

Re: Oil pressure

Posted: Sat Nov 20, 2021 2:58 pm
by Norm57
dcwalker wrote:
Sat Nov 20, 2021 2:12 pm
Thanks Jay, as Alan480 has said, having the gauge just means one more thing to worry about!

By way of update, I've been over to Norm's this morning and we took R3 for a little trip. Hot idle the gauge is in the same place as mine, namely just to the right of the bottom of the white segment. On the 1.7, when hot, according to Haynes, 1000 rpm should be 2 bar, 3000 rpm 3.5 bar. On the basis that it's a 5 bar (70psi) gauge that doesn't have detailed calibration and is not exactly a fine tuned piece of engineering, those readings are what we has.

Norman will continue to monitor but I'm hoping he's a bit more reassured on this question now.

David
Many thanks again DC. I am as reassured as it’s possible to be with a 33 yr old wedge.I believe the car looks at us and waits till we have solved an issue then says what problem can I come up with next!