[Biturbos4] Oil Pressure Light ON!

Keman keman at interwolf.net
Mon Apr 5 12:58:44 EDT 2004

This is not a complicated problem to diagnose.

Step one: Attach gauge to oil pressure sensor port. Measure greater than
20psi? Next.

Step two: Measure output of oil pressure sensor. Sensor ok? Next. no?
Replace. I'm extremely skeptical of this sensor failing, we've never seen
one at the shop go bad. It never gets to this point. See below.

Step 3. Monitor measuring value block for oil pressure, see what ECU is
seeing. Check wiring between sensor. Replace wires or ECU.

Now all that being said, I am 99.999% sure it is the following:

Your oil pump inlet filter is clogged up with burnt crusty bits of oil that
your really hot turbos produce. Oil pressure is fine now, but when you run
the engine for a while and watch the oil pressure, you'll see it get lower
and lower as the little bits in the screen wedge tighter and tighter. Within
15 minutes of driving the light will come back on as they totally block
inlet flow.

All you need is a new oil pump. It comes with a new screen. They are a piece
of cake to put in too because your oil pan comes out with little effort.
Check the screen when you're done, and then you'll understand why I can
never recommend 10k mile service intervals on a turbocharged engine running
non-synthetic. :P

We do oil pumps all the time like this... mostly on four cylinders however.
The Biturbo crowd usually runs their own synthetic by nature of the customer

- Keman

> So about 2 weeks ago, I was driving home from work, and my oil pressure
light beeped and came on.  It was the red blinking oil tin looking thing. So
I pulled over right away, checked oil level. It was a tiny bit low, so I
filled it. The light still stayed on. I drove it over to my mechanic's shop
(which was close), and he said it could be nothing, or maybe more, so I left
it there overnight, and he looked at it.
> So I got it back from my mechanic, and he's not exactly sure what's
happening with it. He put in a new Oil Pressure Sender and changed the oil
(it was due anyway) to 20W50 Synthetic (10W30 before), but the problem is
still there! He's not sure what else could be wrong, since it has more than
enough oil pressure, and he thoroughly tested it.
> With a new sender in place, and the light still on, I don't know where to
go from here.  It's driving me crazy, and I'm afraid that I'm damaging the
car, even though it's been tested and has enough oil volume and pressure.
Is the next step to replace the oil pump?  If so, how much do those usually
run for, and how hard are they to install?
> Please help!!  Thank you!
> Matt
> '00 Nogaro S4 (67k miles)

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