Where is the oil drain plug on a 99 Audi A4 1.8L Turbo?

If the engine has an oil warning light on, there is a possibility of low/no oil flow around the main bearings and turbo etc.
That will cause irrepairable damage.

Unless you do your own work there
is no economical solution,the car has
to be properly repaired

It depends. If you have a turbo engine like the 2.7T, or the 4.2 V8, you should be running a quality synthetic oil like Mobil1. If you have a V6, you're OK running conventional oil (I use Valvoline conventional, 5W30, in my 99 A4 with a 30v 2.8 V6).

it may be bad, i would replace that and see if the light comes back on,its easy to change ive done a few,just drain the oil then remove bolts and remove, install new gasket with new one,theres a way to bypass to test, i belive if you just unplug it or jump the wires,you can try both ways first before replacing it,if it has more than two wires going to it then dont try jumping it, just replace it, good luck.

Does any one have a idea a friend here has changed ecm, inj, fuel pump checked conector at fire wall ,fuel and has a short wrecker tow f450 99 and will be going down the road and he says the thing just loses all power and kind of just won't do over 15 to 20mph and lets it sit and he says it will do it again. I am not sure how long it takes but since I don't work on diesels I figured I would have the experts that do if anyone knows it's you guys any help he is in Charlotte NC I can put you with this guy he has had it to all the parts changers and no luck Thanks Mark 704 492 1647

It needs a turbo.

The oil overfill might well be the cause of the smoke. It will be nothing to do with the overboost. That is quite a common fault and at the main dealers, Audi for me, we usually replace the turbo for that. You need to check the N75 and all the vacuum pipes etc, but when they go you dont get enough boost, when you get to much 99% of the time its the Turbo.

We arent aloud to take turbo's aparts, But In the real word I would suggest you look into having the turbo rebuilt. It is a variable vain turbo and the vains and or the actuator that control them get stuck, which causes this problem. I assume you recently purchased the vehicle, because its very common when its intermittent, for people to see that fault code, know a turbo is £1000 and sell the car.

You can drive around the problem usually, by keeping the revs up. Pulling full throttle from low rpm will bring it on more, thats how we test them.

Transmision oil for 2001 Audi A4 1.8 l turbo:
Manual gearbox (5 speed):
- Capacity = 2,25 liters
- Specification: Gear oil SAE 75 W 90 (synthetic oil)
Part number G 052 145 S2 (1 liter)
- To check oil level, unscrew oil filler plug placed on the left side of the gearbox in front and near of transmission axle, using an Allen 17 mm key.
- Check oil level with locally manufactured tool, e.g. a piece of angled wire.
- Specification: oil level 7 mm below bottom edge of oil filler hole.
- Install oil filler plug, tightening torque = 25 Nm.
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You must first remove the underbody engine pan to gain access to the oil pan. the plug is in the oil pan and is clearly visible.

When the turbo was replaced before, did they change the oil feed and drain lines as well, or just connect the old ones to the new turbo? If they didn't replace them, it's possible one of them is clogged with oil sludge (the 1.8T is famous for sludge). That would be a sure-fire way to kill the turbo.

Stormbrewin is on track with his question too - what was the cause of death of each of the failed turbos?

Yes, you have to do this and yes it is a pin, would highly reccommend taking this to a ASE certified local mechanic who speciallizes in AUDI NOT a dealership