05 BEW TDI Loss of Power and Brakes

Drove home from work last night no issues. Go to go to work this morning, start the car, all seems fine. Going down the hill from my place and go to stop and I notice it's taking a lot of effort to use the brakes, pedal feels hard. Turn around to go back home and check it out and notice I have no power going up hills, seems like the turbo isn't kicking on.

Get back, scan the car, have P0299 for underboost, do some reading and have read about the line cracking between the vacuum pump and booster so I'm checking that line out, remove it to see if anythings cracked and when I disconnected it oil started coming out, checked the vacuum line at the resivor and that's full of oil too.

I've looked at all the lines and can't see any cracks, the car ran last night with no issue. Any idea on what broke and why I have tons of Oil in the vacuum system?

Any advice is appreciated, thanks.

I had this happen to me going down the highway just the other day and now I'm having to replace my turbo. I have the exact same setup you have.

Is the vacuum line alright? The inlet and one outlet was cracked on mine. This will cause the "smart" actuator in the turbo to lose pressure, and the car will go nuts. These actuators cannot be replaced and result in needing to replace the turbo.

If the vacuum line can be replaced and the car still won't start, take off the inlet and outlet hoses for the turbo and check to see if you're getting the suction that you should from the inlet side. If not, you're in the same boat I am right now.

'05 Golf TDI, BEW

Your car has what's called a tandem pump. Tandem because it pressurizes fuel and creates vacuum. If the pump fails and leaks, it'll pass fuel and oil (looks like black oil) into the vacuum system. It can also fill the brake booster with fuel/oil and cause it to fail. I'd see if the oil is getting down the vacuum line to the brake booster. If so, you may need to replace that, but maybe you caught it in time.

Usually the tandem pump fails because the in-tank lift pump has failed some time ago, causing the tandem pump to work harder. Do you hear the lift pump run when you turn the key? If not that may need replacing.