Oil pressure switch

Post by **69gp225** » 04 Jun 2019, 11:29

Hello,

I have an 84 t25 but think the engine has been replaced with an 86?
I had a leaky pressure switch the one near the dipstick.

It was black in colour so I replaced it with the same (black). Looks to be 1.2 to 1.6 bar written on the new one.
Since I’ve replaced it I have an oil light appearing on start up. After a while it goes off but returns on high revs.
Disappears when on idle.

I don’t think the other pressure switch is wired or connected for some reason, it’s near the push rod tubes.. It’s also black in colour. Would it be the same circuit to feed the switch, how And where do I pick the cabling up?
The engine still sounds sweet.

Can anyone help?

Thanks Lee

Post by **DoubleOSeven** » 04 Jun 2019, 15:06

Yup, bit of a head scratcher. Hope this helps. Blue by the push rods, Grey at the front.

Post by **937carrera** » 04 Jun 2019, 16:36

The Dynamic Oil Pressure System works to detect lower than expected oil pressure at speeds above 2000 rpm. Below 2000 rpm only the blue / 0.25 bar provides a warning.

If you take the cable to the rear / black oil pressure switch and earth it, then take the engine over 2000 rpm, the annoying buzzer should be silenced, or it would be if you had all the wiring, as it is I assume the second oil pressure switch has been wired to just activate the red warning light.

Anyway, that's the test to do, which will at least test the wiring.

The oil warning light should not be on at tickover. If it is on an above 2000 rpm, then you need to get the oil pressure checked. It might be low, or it might be the switch.

Oil pressure checks only really mean anything when the engine is hot, so coolant needs to be up at normal running temperature

Post by **DoubleOSeven** » 04 Jun 2019, 18:36

I’m going throw this one out there...Being an early van it would not have any wiring for the front grey switch. Just leave the black switch in the hole as it were, unused. Put the wire that was on it to your new blue switch. That’s my guess anyway.

Got a picture of the engine bay, might help us?

If you’re not sure of the wiring at this stage, put the blue switch in and stick a test light on it. 12V tab on back of alternator. It should light when ignition turned on and got off after a few seconds after start up, i.e. you have oil pressure.

Post by **69gp225** » 04 Jun 2019, 18:47

Thanks guys.

Let me just recap, for some reason both the original switches that are old and installed are both black which is rather weird. Think I will try the wire directly on the lower switch as it may be a simple fix. The engine was taken apart last year so maybe the guy accidentally put the wire on the wrong switch?

Will get some pics on a dryer day.

Thanks Lee

Post by **69gp225** » 15 Jun 2019, 11:31

Can anyone confirm because I have an early van with later engine.
I would use the lower blue switch and not the grey switch.
Hence no wiring for buzzer of doom because it’s an 84 van.
The wire would go to lower blue?

Thanks lee

Post by **937carrera** » 15 Jun 2019, 14:32

Blue goes between push rod tubes

Post by **angleseycaver** » 09 Oct 2019, 19:48

I have an 83 high top auto home, but suspect it may have a later engine, it is petrol water cooled, and has two wires one to a oil pressure switch between the push rods and the other wire going down behind the alternator belt,I have replaced the switch between the push rods and now have the oil warning light flashing, I have since found out I have replaced it with the wrong one and am awaiting the proper one to arrive..any one any thoughts on this ??

Post by **937carrera** » 09 Oct 2019, 20:59

When you get the correct one the light will go out. One switch is normally open, the other normally closed

Post by **angleseycaver** » 10 Oct 2019, 12:20

Thank you Carrera...

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