Oil Pressure Zero on 1Z TDI: Causes & Fixes

Hi everyone, I'm currently at an internet cafe on Crete. On my way to the airport, my ride (presumably a taxi or shuttle) let me down in bus number T3.

After driving for 10 kilometers, the oil pressure warning light suddenly came on, and my oil pressure gauge showed 0 bar.

I have a 1z engine in a T3 with an additional oil cooler. The engine has approximately 60,000 km (about 37,000 miles), of which about 30,000 km (approximately 19,000 miles) were driven in the bus. I changed the oil 500 km (about 310 miles) ago and installed a Bosch oil filter. The oil consumption has been approximately 1 liter per 5,000 km (about 0.6 quarts per 3,100 miles). There is enough oil in the engine, and there are no leaks or other losses.

What could that be?

Can the thermostat for the external oil cooler completely shut off?
Could the bearing in the turbo suddenly fail?
I'm really at a loss; the engine was running smoothly, without any noise or smoke, and there were no signs of overheating.

Could the oil pump be defective?

I'm not familiar with this area, but it might be worth considering.

Hello Joe,

Where do you get the oil pressure reading for your dynamic display, and what type of thermostat do you use with your oil cooler?
I'm not aware of any cooler thermostats that can completely shut off the oil circuit, as there are always bypass openings. The oil filter also has a bypass opening if it becomes clogged. If the oil pressure is measured at the oil filter flange and it's low, then the filter is clogged (but the engine will still be supplied with oil through the filter bypass).
If the oil pressure at the cylinder head (where one of the sensors for the oil pressure light is located) is actually zero or close to zero, then the hydraulic lifters should make a very loud clattering noise (like in the first few seconds after an oil change). If that's not the case, I suspect a faulty reading. An engine running without oil pressure will become louder and rougher just a few seconds after the loss of oil pressure.
I once had a case like this: The oil pressure switch and the dynamic oil pressure sensor were mounted on a T-piece at the cylinder head. A clump of oil sludge had blocked the inlet to the T-piece, causing the red warning light to suddenly illuminate and the pointer on the oil pressure gauge to drop to 0 bar.

Have a great rest of your vacation!

Hello,

hast Du schon den Öldruckgeber durchgemessen ? Are the cables okay over there?

Best regards, Rainer.

Hello, thank you for your replies. Here are some more details:

The VDO oil pressure indicator is mounted on the oil pressure flange.
I purchased the oil cooler thermostat from Reinhold Mayer, who specializes in oil coolers for T3 buses.

The bus was immediately parked and towed home. I am currently still in Greece and trying to figure out the cause (which is why I can't type umlauts, as I'm using a Greek keyboard).

Where is the oil filter bypass located? If it's engaged, will there be no pressure at the oil filter flange?