Buzzer of doom - confused with it

[Shinnster]

Hey all,
Took my van from London to Dubs at the mill this weekend which was a nice 250 + mile round trip. The van ran smooth, no issues really, apart from the damn buzzer going off.
It seemed to happen after long stints of driving and then when I either went uphill or slowed down so the revs were below 2k? (i think) the buzzer would go off and the oil light come on.
This scared me at first as I assume thats kinda bad! But if i just sped up or changed down gear to get up the hill it would stop .

What causes this? and is it something i should be overly concerned with?
I thought maybe the oil was getting hot and thinning out?
I currently use 10w 40 mineral oil .

E D I T: the water temp stayed below half all the time and oil level stayed the same.
I put the wrong oil, i'm currently using 15w40 mineral oil.

 

[Mocki]

Sounds like the warning is actually behaving as designed , first thing to do is a visual inspection of the wiring for the oil pressure senders in the engine bay , ( as you haven’t told us, i will assume its a WBX) look for dirty green connections and or damaged insulation on the wiring, particularly near the exhaust header near the electrical box in the engine bay , there is ( or would have been originally) a two pin white connector where the oil pressure wires change from brown to yellow/red and green/black * take this apart and check its not all corroded . If you find nothing to convince you its a wiring issue get the oil pressure checked before you drive it in anger again .



*colours maybe wrong, I haven’t checked the wiring diagram and am only typing from my old memory

[Shinnster]

sorry, it is a 1.9 dg
So as long as the buzzer / light goes away the engine is back to fine?

I'll have a look for the wires tomorrow and see what I can find.
thanks for the swift reply!

[Mocki]

It is designed to warn if the oil pressure is reported as low above 2000 rpm , if you drop lower its not reporting it , it doesn’t mean the oil pressure isnt low .
A oil and filter change (Mineral 15/40 and Mann filter) some wrong filters do not have the correct spec for this engine and Dops system

[Robsey]

there is ( or would have been originally) a two pin white connector where the oil pressure wires change from brown to yellow/red and green/black ...

colours maybe wrong, I haven’t checked the wiring diagram and am only typing from my old memory.

Just to confirm it is-
Yellow for the higher pressure switch.
Blue/black for the lower pressure switch.

My understanding is that it is the higher pressure switch and wiring that needs to be checked.
So the yellow wire circuit.


The yellow/red is the gauge coolant temperature sender wire.
Paired with the blue/green for the coolant level switch.

[Mocki]

See i knew i was misremembering , i knew those colours were local to that junction tho….. lol

[Shinnster]

had some time today so checked over the wiring an it looks good, no corrosion or dodgy wiring to speak of.
i gave it an oil change to 15w50 and a new mann oil filter.
At the weekend i'll give it a good long run and see if the issue reoccurs.
hopefully not!

[escovedo]

there is ( or would have been originally) a two pin white connector where the oil pressure wires change from brown to yellow/red and green/black ...

colours maybe wrong, I haven’t checked the wiring diagram and am only typing from my old memory.

Just to confirm it is-
Yellow for the higher pressure switch.
Blue/black for the lower pressure switch.

My understanding is that it is the higher pressure switch and wiring that needs to be checked.
So the yellow wire circuit.


The yellow/red is the gauge coolant temperature sender wire.
Paired with the blue/green for the coolant level switch.

My understanding of the system was yellow wire the low pressure switch
blue/black high pressure switch? unless the Haynes manual is incorrect.
 

[AngeloEvs]

 Mocki is correct     Pin 13  Blue/Black -  Low      and Pin 12  Yellow - High

[ajsimmo]

I'd say your oil pressure is borderline at 2k rpm. (Spec is 2bar at 80°C). If you have a 1.8bar switch in you can safely change it to a 1.4bar (VW just changed it to a 0.9bar back in the day to stop all the warranty jobs!). As belt n braces, up your oil grade to 15W50, and that'll give you a touch more pressure when hot.

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