Oil pressure light

[oddnumber]

I've just had the oils changed in my 1.9 wasserboxer to 10w40 - it had 20w50 in it. Now after a motorway run when got I'm getting a solid oil light at idle. If I blip the throttle slightly it goes out.

Could the thicker oil have been masking a problem? I'm tempted to chuck the heavier stuff back in and ignore it.

Anyway, my question is is 20w50 within vw spec or generally considered too heavy?

[jimpainter]

15/40 mineral is what I use. These engines don't like synthetic oil, some mixed results with semi synthetics.
Have you got the right pressure switches in (pressure rating) the thicker oil would have increased pressure a bit. Just check switches first, then maybe try swapping oil again just to rule things out.

Jim

[AdrianC]

These engines don't like synthetic oil, some mixed results with semi synthetics.

<groan> Not this _again_...

The VW owners manual for late WBXs specifically recommends synthetic oil.

[oddnumber]

Thanks chaps. Don't want to cause a mineral/synthetic argument. Was just wondering if the 20w50 was still in spec?

[AdrianC]

Was just wondering if the 20w50 was still in spec?

At the thicker end of it, but yes. Don't worry so much about the 20 - that's the cold viscosity. It's the hot viscosity you're needing to be a higher number, therefore thicker, than 40.

20w50 used to be the cheapest and nastiest of all oil, though... I'd definitely be looking for a decent brand and plenty of manufacturer approvals on the bottle.

[jimpainter]

These engines don't like synthetic oil, some mixed results with semi synthetics.

<groan> Not this _again_...

The VW owners manual for late WBXs specifically recommends synthetic oil.