Changing the supercharger oil on your Audi's 3.0t engine isn't a necessity; Audi themselves say that the oil is for life. But tuners and owners alike have found no harm in changing the supercharger oil, especially with an engine running more boost. The oil change itself is easy to complete and cheaper than an engine oil change. If you have the supercharger off of the car for any reason, you're able to give yourself that extra peace of mind for no hassle at all.
Removing the supercharger on your B8/B8.5 Audi S4 isn't a terribly difficult job. Remove a few vacuum hoses, coolant lines, and a couple of bolts, and it pops right off. The process on the S4 will be relatively the same across the board for any Audi 3.0t engine, such as the S5, SQ5, Q5, A6 Quattro, A7 Quattro, and A8 Quattro. While you have the supercharger off, why not clean your intake valves, or make the car go faster?
Audi models and years applicable:
How much will it cost to replace the supercharger oil in an Audi S4?
Put aside around $100 for the parts needed to change the oil. The oil bottle is $41, the gaskets total around $18, and the PCV hose is $4. Use the rest of the budget on rags, brake clean, and extra coolant.
How long will it take to replace the supercharger oil in an Audi S4?
The longest parts of this job are the supercharger removal and reinstallation. Changing its oil is a quick process. Set aside a couple of hours to complete the DIY.
Parts required to replace the supercharger oil in an Audi S4:
- Audi Supercharger Oil
- Audi Intake Manifold Gasket x6
- Supercharger Bleeder Screw Kit (Optional/Recommended)
- Audi Coolant
- Audi PCV Hose
Tools required to replace the supercharger oil in an Audi S4:
Steps required to replace the supercharger oil in an Audi S4:
Step 1: Remove the supercharger
Start by removing any vacuum line from the intake tube. Use an 8mm socket to release the hose clamp for the intake tube on the throttle body and pull up on the airbox to remove it from its mounting grommets. Then, remove the intake assembly from the engine bay.
Next, remove the engine dress-up covers to reveal the sensors and solenoids behind the supercharger.
The vacuum lines on the back of the supercharger all have their specific places. Use something like a sharpie to mark the lines to ensure that they don't get mixed up during reinstallation. Then, disconnect all of the electrical connections from the back of the supercharger.
Next, remove the evap hose from the throttle body.
On either side of the supercharger is a MAP sensor. Pull up on the white tab and disconnect the sensors.
In between the MAP sensors and the valve covers are long and thin plastic covers. The removal process will be different depending on the model year. Early 3.0T models must use a T25 Torx socket to remove two bolts that fasten down the cover. Later models need a pick to lift on the left side cover's locking tabs and the T25 for the right side cover.
Next, take a long 16mm wrench and slide it between the front of the engine and the radiator to loosen the supercharger belt tensioner. Position the wrench on the tensioner's bolt and rotate it to the right. Then, pull the belt off of the supercharger.
If you are reusing the belt, you can leave it in place after you slip it off of the supercharger. Then, head over to the coolant expansion tank and open the cap to relieve the coolant system of its pressure.
Then, remove the clamps from the two coolant lines on the front of the supercharger. Use a pick to break any coolant build-up preventing the hose from moving before pulling the hose off the supercharger.
The coolant hoses mount to the engine on the driver's side cylinder head. Use a T30 Torx socket to remove the bolt and allow the hoses to move freely. Then, pull the coolant hoses off of the supercharger.
Next, use a 16mm socket to remove the six nuts securing the supercharger to the intake manifold.
Place some rags or absorbent cloth over the radiator support and front bumper to catch any fluids that may come out of the supercharger as you remove it. Then, place ratchet extensions through the loops on opposite corners of the supercharger to create makeshift handles. Use those handles to lift the supercharger off of the engine.
Step 2: Replace the supercharger oil
Prop up the front of the supercharger and use the 3/16 hex bit to remove its fill plug.
Then lift and tilt the supercharger to let the old oil drain out into a cup. The superchargers don't get a set amount of oil, so you'll need to measure the amount you poured out.
Once you measure what came out, rinse the measuring cup out, and fill it with the new oil. Then, pour the new oil into the supercharger. Use the 3/16 hex bit to thread the fill plug back into the supercharger and snug it up.
Step 3: Reinstall the supercharger
First, reconnect the secondary air-line and refit any insulation pieces that you may have removed during the job. Then, remove the old, green supercharger gaskets and replace them with new ones.
Next, lightly lubricate the o-rings of the new supercharger breather pipe and press it into the engine. Then lay the insulating engine valley cover over it.
Now, grab the supercharger and seat it onto the engine. Ensure that all of your vacuum lines and sensor wires for the back of the supercharger are not getting pinched or trapped under it as you press it onto the engine. Then, thread on the six 13mm nuts onto the supercharger mounting studs.
Torque the supercharger nuts to 20Nm. Next, attach the coolant hoses to the front of the supercharger and clamp them down. Then, use a T30 Torx socket to install the bolt that secures the coolant lines to the engine.
Next, reconnect the vacuum lines and three electrical connections on the back of the supercharger. Then, move to the other side of the engine and reattach the throttle body's electrical connections.
After that, install the covers that sit under the MAP sensors on either side of the supercharger. Use a T25 Torx socket to tighten the bolts. Then, reconnect the MAP sensors on either side of the supercharger.
Next, reach down in front of the engine and pull up the supercharger belt. First, ensure that the belt is still correctly oriented on the engine's pulleys. Then, use a long 16mm wrench to release the tension from the belt tensioner. While holding the tensioner, use your other hand to reinstall the belt onto the supercharger.
Step 4: Refit the intake
Take the intake assembly and fit it into the engine bay. Attach the intake tube to the throttle body, then seat the airbox into place. Clamp the airbox down and use an 8mm socket to tighten the intake hose clamps.
Lastly, attach the vacuum line to the intake.
Step 5: Fill the coolant and test the engine
Open the expansion tank and fill it with coolant. Then, open up the bleeder screws on the supercharger. Start the car and run it, allowing the air to bleed from the cooling system. Keep an eye on the coolant level and add it as you see fit.
As the engine runs, check for any coolant or fuel leaks. If everything checks out, jack up the front of the car and reinstall the undertray. Slide the front of the tray into the bumper and lock the tray into place with a T25 Torx socket or screwdriver.
If you have any questions or comments about replacing the oil in your Audi's supercharger, leave them in the comments section below.
Owner of a flat-six swapped 1998 Impreza 2.5RS and a 1973 Porsche 914. Horizontally opposed views, only.