I did a lot of online search and bought a Haynes manual but could not find answer.

I bought a 2005 POLO 1.2 55bhp two months ago, with mileage of 75000. There are no service history for recent years. I have no idea what kind of oil was used before, but its colour was not too dark. According to the documents together with the car, it is 9N1 OB4, with engineer code of BMD. It had been driven fine for several hundreds miles.

Several weeks ago, there was a low engine oil level warning, therefore I added a few fully synthetic 5w30. From then, there started to have problems of the low oil pressure light. I took the car to a local garage, with oil changed to fully synthetic 5w30. The problems remains.

The details of the problems:

1) When I turn the ignition on but before start the engine, the warning light comes on for a moment and then goes out.

2) After the engine is started, there is no warning light.

3) If the car is at idle after the engine is started, there is no warning light.

4) If I drive the car with engine below 1500 rpm, there is no warning light.

5) If I rev the engine over approximately 1500 rpm, there start to be a flashing warning light with warning beeper sounds for a few seconds. Then the sound stops but warning light remains on.

6) If I reduce the rev immediately the warning light usually goes out. But if I drive the car for a little longer with the warning light on, the warning light will remain even at low rev or idle.

I did some research, it looks like VW use dynamic oil pressure system. The above problems might be caused by a faulty high oil pressure switch, which normally is located on the oil filter flange. But I can not find the switch!

My questions:

1) Is the car installed with 2 pressure switches or only one? There is only one switch mentioned by Haynes manual, which should be located on the left-hand end of the cylinder head.

2) Where can I find the pressure switches? I must be silly but I really can not find any of them.

3) How can I buy pressure switches? I searched ebay, but their pressure setting are all pretty low?

4) What possible problems the car has? Shall I take it to the dealer for diagnosis?

Your advice would be highly appreciated. Thank you.

Oil pick up partly blocked??, had the same problem with one that came in to my workplace, serviced it, 2 weeks later came in with oil light coming on, oil level fine, changed oil to vw's recommended oil, still the same, no oil light on when driving on bypass but town driving came on constantly, turned out to be partly blocked oil pick up, common though vw, seat etc

I did a lot of online search and bought a Haynes manual but could not find answer.

My questions:

2) Where can I find the pressure switches?

Your advice would be highly appreciated. Thank you.

Hi

Have you managed to see where the oil pressure switch is on your car ?

Oil pick up partly blocked??, had the same problem with one that came in to my workplace, serviced it, 2 weeks later came in with oil light coming on, oil level fine, changed oil to vw's recommended oil, still the same, no oil light on when driving on bypass but town driving came on constantly, turned out to be partly blocked oil pick up, common though vw, seat etc

Thank you.

I did a lot of online search and bought a Haynes manual but could not find answer.

My questions:

2) Where can I find the pressure switches?

Your advice would be highly appreciated. Thank you.

Hi

Have you managed to see where the oil pressure switch is on your car ?

I tried but can not find the switch. I took a few pictures of the car, which will be posted soon

Any one would advise where is the oil pressue switches?

There is no pressure switch on the oil filter flange.

Is this the oil pressure switch on the cylinder head? but this is not located on the left-hand end of the cylinder head.

I'm guessing you have a BMD engine code ??

#14 0.3~0.7bar oil pressure switch F1 25Nm

Thank you very much. Will try to find it tomorrow.

Thank you Nige. Yes it is BMD engine. I found the switch as your information and already ordered one to replace.

I replaced the switch today. Still got the same problem.

I also tried to disconnect the wiring and the switch and the start the engine. The problem remains the same.

Then I connected the wiring to the engine case (not sure I did correctly), but still no difference.

Any advice?

No idea if it's applicable but it's a relatively easy fix. Had a similar issue with my '83 breadvan. Turned out the oil was too thin. Sensor couldn't sense it when it warmed up. Used thicker oil and all was good.