Oil pressure light on when driveing at 50 MPH por more

DEETS33

MEMBER
2001 AUDI A4
92,500 MILES

The engine is 1.8T, The head was just rebuilt because the mechanic didn't have everything set correctly after replacing the Timing Belt Kit, resulting in some damage. Replaced some valves and head was machined. Oil light now comes on at highway speed above 50 MPH. Oil sensor was replaced, still comes on. One other problem there was no heat from heater - they flushed heater core, so far seems to have taken car of heat problem. Oil light coming on concerns me. They are just scratching their heads.

Wednesday, May 2nd, 2012 AT 9:20 PM

3 Replies

CADIEMAN

MECHANIC
3,544 POSTS

At 50 u would hear lifter clatter if the pressure is low. Replace the sending unit again. If no u will to remove the head and ck the wire for conituity from the sensor to the light.

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Wednesday, May 2nd, 2012 AT 9:47 PM

FIXITMR

MECHANIC
9,990 POSTS

Are the oil drains in head ok? Maybe pump runs low on oil because of slow drains?

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Wednesday, May 2nd, 2012 AT 9:50 PM

EXOVCDS

MECHANIC
1,883 POSTS

The main problem with the 1.8t engine is sludging from using the wrong oil or waiting too
long between oil changes.

The system checks for oil pressure at 2000rpm. If it does not get a ground signal at that
rpm, then the oil warning will come on.

You need to attach a mechanical oil pressure gauge in place of the oil pressure switch to see
what the actual pressure is once the engine is fully warmed up.

A scan tool can be used to access the instrument cluster to view oil pressure switch status.

If less than 30 psi of pressure is present at 2000 rpm or above, remove the oil pan and
check the pickup screen for sludge / restriction.

Thomas

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