Why would an Audi RS6 engine need to be replaced? An Audi that shuts down and won't restart with low compression may have jumped timing. In this RS6, sludge blocked oil to a timing chain tensioner, and the engine needed to be replaced.
The problem
The owner was driving on the highway when his Audi RS6 shut down and wouldn't restart. It was towed to us. A compression test showed no compression on the left side of the engine only. That pointed toward bent valves.
How we found the cause
The outer timing belt was fairly new and the timing looked right. On many Audi and Volkswagen engines there is both an outer belt and inner timing chains. Each cylinder head has two camshafts. The belt turns one and a chain turns the other.
After removing the valve covers, we found the left bank was off by about 180 degrees. The chain tensioner compressed with one finger, which it shouldn't. The oil passage to it was plugged solid with engine sludge, so it couldn't hold tension and the chain jumped.
The options we gave the owner
- Start looking for another car.
- Remove the engine and repair what's broken.
- Remove the engine and rebuild it completely.
- Replace the engine with a new one.
- Replace the engine with a low mileage used one.
He chose the used engine. It was the most cost effective and fastest choice. We resealed the engine, replaced the outer timing parts and brought the maintenance up to date.
What it takes
On this car the front end comes off to get the engine and transmission out together. The job took roughly 45 hours, and the car was back running perfectly in about a week and a half.
Questions we hear
How often should an Audi timing belt be replaced?
Many Audi and Volkswagen engines call for it around 90,000 to 100,000 miles. It's usually done with the water pump, tensioner and seals. Check your owner's manual.
What causes engine sludge?
Missed oil changes, short trips and the wrong oil can all build sludge. Regular oil changes help prevent it.
Do you work on Audi?
Yes. See our Audi service and timing belt pages.
Protect your engine with on time service. Book online or learn about our engine repair.
