Oil warning just randomly comes on.

Please help my oil warning starts randomly buzzing but my oil level is fine? Very annoying and loud.
Thanks Scott

Well that is usually an issue with a corroded connection on the "High RPM low Pressure switch" on the oil filter flange (white).  So with that being the issue I would ask
the following.

Have you cleaned and tightened the connector on the sensor (under the rubber cap).

Have you replaced that sensor?

What oil vis are you running?

What is the oil pressure on the car when this happens?

Why, because I had a similar issue and I had 3.5 bars pressure running down the road, it was the connector being loose on the engine.

I have had the pressure bypass go wonky on my car, so I opted to install the 2.0L oil pump.

I have seen on my car when it was "new to me" do strange things on my 500 mile drive home, I changed the oil over to 20w50 and a good filter (FRAM) was on it and the issue went away.

Now if you haven't replaced your Battery to Frame and Frame to engine grounds or cleaned them up at the least, that is the first thing I would do…. after changing the sensor.  If the issue still occurs, then I would be getting a mechanical reading of the oil pressure as I was driving….. or swap a new oil pump in there.  

Briano1234 said

Well that is usually an issue with a corroded connection on the "High RPM low Pressure switch" on the oil filter flange (white).  So with that being the issue I would ask
the following.

Have you cleaned and tightened the connector on the sensor (under the rubber cap).

Have you replaced that sensor?

What oil vis are you running?

What is the oil pressure on the car when this happens?

Why, because I had a similar issue and I had 3.5 bars pressure running down the road, it was the connector being loose on the engine.

I have had the pressure bypass go wonky on my car, so I opted to install the 2.0L oil pump.

I have seen on my car when it was "new to me" do strange things on my 500 mile drive home, I changed the oil over to 20w50 and a good filter (FRAM) was on it and the issue went away.

Now if you haven't replaced your Battery to Frame and Frame to engine grounds or cleaned them up at the least, that is the first thing I would do…. after changing the sensor.  If the issue still occurs, then I would be getting a mechanical reading of the oil pressure as I was driving….. or swap a new oil pump in there.  

Ok mate thanks that's great thanks for your help

Hi I am new to the mk1, just bought my golf gti mk1.
I have a similar problem, the oil pressure light come on with ignition and stays on flashing after the engine started and sometimes the buzzer comes on too but buzzer goes off if I rev the engine. I have replaced the high pressure switch.  I also disconnect the low pressure switch and ground the wire but it doesn’t stop the light flashing. Just wonder if there is any suggestions I could try next? Many thanks.

If I remember rightly this is potentially an earth issue

rubjonny will know, as he's an electrical clever clogs    

Today the problem got worst, I took her out for a spin and as I turned  the ignition on both the light and buzzer came on with the engine off. No matter what I did followed the guide posted here to check the sensors but it just won't go away. I drove it for about 15 mins the buzzer suddenly went away but the light stayed on for the rest of time.
Yes I have read a few posted by John and others and I will try to swap the L shape circuit board hope it is still available. I will update once done.
Cheers

have you replaced your battery to frame and frame to engine/tranny grounds?

if its an MFA cluster check the clock earth to the side of the head, its a brown/white wire with ruing terminal.

also look for the connection behind the fusebox for this earth between the dash loom and engine loom, its a spade plug near the fusebox.

pull the plug off the clocks, check all the pins are straight and clean. if any are squished down you can carefully use a pick tool to straighten, but pull the live fuse for the clock out first otherwise the red wire will be live. For easier access you can open the flap on the rear of the plug to pull out the pins, just take care not to pull them all out and loose the order. Take a picture first just in case

the main pcb on the cluster can get worn as well, an excellent tip from Chortle was to pack it out from behind, also often the plug clip housing is missing off the bottom which means the main plug doesnt fit very securely so be sure to replace that if its gone walkies.

Just bought a replacement L shape circuit board from eBay, and will try to locate the earthing point mentioned by John first before I dismantle the speedometer. I will disconnect the battery first just in case. Will update when done.
Cheers for the the help.

At last have the time to swap the circuit board. At first it doesn't make any difference, it stil buzz like crazy, then I start cleaning all the connections as John mentioned.Make sure all the pins are straight. Result!! It stops buzzing, so I put the old one back and it works as well. Not only that, I use to have starting problem with it , I need a little throttle to start it up. Now it just start with a turn of the key with no problem. So it was electrical connection all along and what a huge difference it makes.

Never can discount cleanliness on connections.
Glad you got it sorted.

just goes to show, you should always try the free checks first