[geodr]

I am original owner of 1999 Passat GLS Wagon 1.8T, 144k miles. For the past few years the low oil pressure indicator would occasionally go off when driving up steep hills here in SF Bay area, but overall the car continued to run okay - I just attributed that to it being an old car. A couple of weeks ago, right after a car wash (any hint there?) the low oil pressure indicator started going off continually while driving at moderate speeds on level ground. After not more than 5 miles it took to get home, I stopped driving and had it towed to a garage.

The garage (specializes in German cars) tried replacing the sensor, said that wasn't the problem, and then went ahead and changed the oil pump, and noted a clogged intake tube (sludge), which was replaced too. But now the garage says the car is running with slightly low oil pressure just at the limit of the sensor (1.4 bar = 20.3 psi), so the sensor is still continually signalling low oil pressure. The garage wants to put in a sensor that triggers at 1.3 bar (18.9 psi).

Two questions:
Is it safe to run the car at this lower oil pressure?
Is the garage missing anything obvious?

Thanks from a noob.

 

[Tomvw]

Actual hot oil pressure readings would give us something valid to base opinions on.
The pressure should be checked at idle, 2000 RPM, and 3000 RPM after driving for at least 20 minutes.

The system only checks the oil pressure when the engine is above 1500 RPM, if the light circuit is working properly and the light comes on
while driving, the actual oil pressure at idle will be well below the light trigger psi.
This would not be very safe for the engine but it is questionable whether it would be worth fixing, as you likely have damaged cam shaft bearings
which would require a replacement head, and there may be other bearing etc problems.

If you don't push it too hard it will probably last a reasonable time as is.

 

[PZ]

You should be fine with 20psi at hot idle as long as the pressure rises with the rpm. Hopefully the turbo was not damaged during the 5 mile drive home.

 

[Tomvw]

PZ, his hot idle pressure is well below 20 psi.

 

[TurboJim]

What caused sludge to form in the first place? Couple of suggestions - service the PCV system on a regular basis and along with quality synthetic oil use a Big Kahuna size oil filter. Keep your oil change interval at 5,000 miles max.