Oil on the crank pulley, a burning smell after a long drive, or a puddle that showed up right after a belt let go? Meet the Audi 3.0T front main seal, a small part with a big job: keeping engine oil inside the block where the crankshaft pokes out the front. On the supercharged EA837 V6 the factory seal is a thin stamped-steel wiper design, and it has a nasty habit of dying the same day a belt does. That is exactly why we sell a billet aluminum front main seal for the Audi 3.0T built to replace that weak point. Here is how to spot a leak, confirm it, and fix it once.
What the Front Main Seal Does on the EA837
The front main seal, also called the front crankshaft seal, sits in a holder on the front of the engine block, right behind the crank pulley. The factory part number is 06E 103 153 E. The crank pulley bolts to the nose of the crankshaft and drives both the accessory belt and the supercharger belt, so the seal lives in the busiest neighborhood on the engine: spinning metal, two belts, heat, and crankcase pressure pushing from the inside.
When it is healthy, you never think about it. When it fails, oil escapes at the exact spot where it can be thrown onto your belts. That is a bad combination on an engine whose supercharger depends on one of those belts.
Signs Your Audi 3.0T Front Main Seal Is Leaking
- ✅ Wet oil on the back of the crank pulley and on the front of the block directly below it
- ✅ Oil flung onto the belts, belt squeal on cold starts, or a belt that slips under load
- ✅ Drips under the front of the engine, often landing on the belly pan first
- ✅ A burning oil smell after a drive as oil hits hot parts
- ✅ An oil level that keeps dropping between changes
- ✅ A sudden oil leak right after a belt failure, sometimes with rough running
That last one deserves its own section, because it is the most common way this seal fails on the 3.0T.
Why a Broken Belt Takes the Front Main Seal With It
Belts on the 3.0T work hard. When one cracks and shreds, the fragments do not politely fall on the ground. They can wrap behind the crank pulley and get pulled into the factory wiper seal. That thin stamped-steel design can shred and ingest belt material, and once it is torn or pushed out of place you have an oil leak, oil on everything, and a car that is not going anywhere until it is fixed. A failed seal can also upset crankcase pressure, which in some cases shows up as rough running or misfire codes.
So when a belt goes, do not just throw a new belt on and call it done. Look hard at the front main seal, and look at what killed the belt in the first place. On the supercharger drive, the factory tensioner pulley is plastic, and with mileage, heat and belt load it can crack or distort and throw off belt tracking. Our billet supercharger tensioner pulley for the Audi 3.0T replaces it with CNC-machined 6061 aluminum and a pre-installed bearing.
Make Sure It Is Really the Front Main Seal
Oil runs downhill, and on the 3.0T plenty of other leaks end up at the front of the engine. The usual impostors are the oil filter housing gaskets and the valve cover gaskets. Before you buy anything:
- Clean the front of the engine and the crank pulley area with degreaser.
- Drive the car long enough to get it fully warm, then park it on cardboard.
- Look with a flashlight. Fresh oil directly behind the crank pulley points to the front main seal. A wet trail coming down from higher on the engine points somewhere else.
- Add UV dye to the oil if the source still hides from you.
If the trail leads up to the oil filter housing, our TruSeal oil gasket upgrade and a new EA837 oil filter housing are the fix, and our oil filter housing gasket guide walks through the job. Weeping from the top of the heads? The 3.0T valve cover set is the usual answer.
Factory Seal vs Billet Front Main Seal vs Dealer Repair
In short: a dealer repair puts the same stamped-steel wiper seal back in, so the weakness comes back with it. Our billet front main seal swaps that design for a CNC-machined 6061-T6 aluminum holder with an OEM Viton seal from Elring, an integral tension spring and Grade 12.8 hardware, for $124.99.
| Factory seal | Vorsprung billet front main seal | Dealer repair | |
|---|---|---|---|
| Seal design | Thin stamped-steel wiper seal | Elring Viton lip seal with integral tension spring | Same factory wiper seal |
| Holder | Factory | CNC-machined 6061-T6 aluminum, gloss black anodized | Factory |
| Belt debris | Can shred and ingest belt fragments | Built to replace that weak point | Same weakness returns |
| Crankcase pressure | Stock tolerance | Holds up to higher crankcase pressure, per the listing | Stock tolerance |
| Hardware | Reused factory hardware | Grade 12.8 hardware included | Factory hardware |
| Price | Included with the car | $124.99 | Dealer pricing plus labor |
Already planning a belt service? Add the Vorsprung billet front main seal and close up the front of the engine knowing the next shredded belt is not going to turn into an oil leak.
Shop the Billet Front Main Seal, $124.99
✅ OEM Viton seal from Elring · ✅ Fitment help by VIN at help@vorsprungautowerk.com · ✅ Free US shipping on orders over $425
What Is in the Vorsprung Billet Front Main Seal Kit
- ✅ CNC-machined 6061-T6 aluminum seal holder, finished in gloss black anodizing
- ✅ OEM Viton seal from Elring with an integral tension spring
- ✅ Grade 12.8 mounting hardware, so the kit is ready to install
The listing is currently marked as a pre-order, so check the product page for the ship date before you book the shop time.
Audi 3.0T Front Main Seal Fitment
The billet front main seal fits the EA837 3.0T supercharged engine in the 2010 to 2016 B8 and B8.5 S4, the 2013 to 2017 S5 plus the 2010 to 2012 S5 Cabriolet (the 2008 to 2012 S5 coupe has the 4.2 V8), the 2013 to 2017 Q5 3.0T, the 2014 to 2017 SQ5, and the 2012 to 2015 C7 A6 and A7. It also fits the European-market B8.5 A4 and A5 3.0 TFSI. It does not fit the EA839 2.9T or 3.0T twin-turbo engine. Not sure what you have? The engine code is on the vehicle data sticker, or email us your VIN.
Shopping for the rest of the car? Everything we make for these engines lives in Audi 3.0T performance parts.
Install Notes
- ✅ Belts and crank pulley come off. Access varies by model, so follow the factory procedure for your car and support the work area properly.
- ✅ Use new crank pulley bolts. Our Unzerstörbar crank pulley bolt kit includes 8 Grade 14.9 M8 bolts (interchange N 910 059 02) and blue thread locker, torqued to 40 Nm per the listing.
- ✅ Clean the sealing area and the crank nose before the new seal goes on, and lightly lubricate the seal lip.
- ✅ Inspect both belts and the tensioner. A belt that already failed once will fail again if the cause is still there.
- ✅ Check for leaks after the first drive and again after a few heat cycles.
Tuning the car? With the pulley already off, this is the cheapest moment you will ever get to fit a TruDrive crank pulley upgrade for the 3.0T, which pairs with a matching single- or dual-pulley tune. Our Audi supercharger upgrade guide explains how pulley sizes fit into a staged build, and the tensioner pulley replacement cost guide covers the belt side of the job.
Audi 3.0T Front Main Seal FAQ
What is the front main seal on an Audi 3.0T?
It is the front crankshaft seal (factory part 06E 103 153 E) that keeps oil inside the engine where the crankshaft exits the front of the block, right behind the crank pulley that drives the accessory and supercharger belts.
What are the signs of a leaking front main seal?
Oil on the back of the crank pulley and the front of the block below it, oil flung onto the belts, belt squeal or slip, drips under the front of the engine, a burning oil smell and an oil level that keeps dropping.
Why does a broken belt damage the front main seal?
When a belt shreds, fragments can wrap behind the crank pulley and get pulled into the thin stamped-steel factory wiper seal. Once that seal is torn or pushed out of place, oil starts leaking at the front of the engine.
Can I drive with a leaking front main seal?
A light weep can be monitored by checking the oil level often, but a seal damaged by a belt failure can lose oil quickly and contaminate the new belts. Fix it before driving the car hard or far.
How do I know it is the front main seal and not the oil filter housing?
Oil from the oil filter housing and valve cover gaskets runs down the engine and can collect at the front. Clean the area, drive the car, then look for fresh oil. Wet oil directly behind the crank pulley points to the front main seal; a wet trail coming from higher up points somewhere else.
What should I replace while the crank pulley is off?
Inspect or replace the accessory and supercharger belts, check the supercharger tensioner pulley for play, and use new crank pulley bolts. It is also the cheapest time to fit a crank pulley upgrade if you are tuning the car.
Do I need special tools to install the billet front main seal?
The billet seal comes in its own holder with mounting hardware, and the listing calls for standard hand tools once the belts and crank pulley are off. Follow the factory procedure for your model when you remove and refit the pulley.
Does the billet front main seal fit the EA839 or 4.0T?
No. It fits the EA837 3.0T supercharged engine only. The EA839 2.9T and 3.0T twin-turbo engines and the 4.0T V8 use different parts.
Bottom Line on the Audi 3.0T Front Main Seal
The factory front main seal is fine right up until a belt shreds, and then it becomes the most expensive oil stain you have ever owned. Confirm the leak is really coming from behind the crank pulley, fix whatever killed the belt, and replace the seal with one built to survive the next failure. Grab the billet front main seal for the Audi 3.0T, add fresh crank pulley bolts, and stop paying the Audi Tax on the same leak twice.
Shop the Billet Front Main Seal, $124.99
Drive the difference. Drive Vorsprung.
Prices checked October 14, 2026 and subject to change.
