Dx oil light flashing after above 2.5k for seconds

Hi all 

Just want to know what I need 

Im guessing an oil pressure switch but which one 

It's on an 88 dx cabby where is the switch and which one do I need to buy thanks 

You may find you have two oil switches, both have different tolerances, Generally, white cap, and blue cap, but this can depend on manufacturer. May as well replace both.

Ok and where can I find them thanks 

VW sold them last year.
Just check which colours they are.
It could also be something else with your oil light flashing, faulty connection to the dash or there is a problem with oil pressure and your oil pump is on the way out.

Same happened to me as I had bought the wrong switches with too low pressure.

Swap them for the ones above.

white one should be on the oil filter housing, blue or brown in the side of the head.

though if the light flashes above 2.5k the buzzer should also go off, if its not then your clocks may be duff or a bad earth somewhere. check the wires to the side of the head