Ausi S5 compression lost in cylinder 4

S

S5 2018

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Wolverhampton, West Midlands, United Kingdom
Hi everyone,

I'm hoping someone can offer some advice or recommend a specialist.

My 2018 Audi S5 Sportback (EA839 3.0 TFSI, 105,000 miles) developed a rough idle which progressively became worse. The engine management light come on, then started flashing. Another warning light came on drive system fault.

RAC diagnostics found:

  • P0300 – Random/Multiple Misfire
  • P0303 – Cylinder 3 Misfire
  • P0304 – Cylinder 4 Misfire
  • P0363 – Fueling Disabled Due to Misfire
  • P0507 – Idle Control
RAC suspected coil 4, but replacing/testing it didn't resolve the issue.
An independent garage has since carried out further testing and confirmed that cylinder 4 is significantly down on compression. Their report states that they suspect a roller rocker bearing issue, potentially causing damage to the camshaft or valves, but they don't carry out internal engine repairs.
I'm now looking for an engine specialist. Has anyone experienced this on this engine?

  • Was it the roller rocker?
  • What was the eventual cause?
  • Can anyone recommend a specialist in the Midlands or elsewhere in the UK who has experience rebuilding these engines?
Any advice would be greatly appreciated.
 
S5 2018 said:
Hi everyone,

I'm hoping someone can offer some advice or recommend a specialist.

My 2018 Audi S5 Sportback (EA839 3.0 TFSI, 105,000 miles) developed a rough idle which progressively became worse. The engine management light come on, then started flashing. Another warning light came on drive system fault.

RAC diagnostics found:


  • P0300 – Random/Multiple Misfire
  • P0303 – Cylinder 3 Misfire
  • P0304 – Cylinder 4 Misfire
  • P0363 – Fueling Disabled Due to Misfire
  • P0507 – Idle Control
RAC suspected coil 4, but replacing/testing it didn't resolve the issue.
An independent garage has since carried out further testing and confirmed that cylinder 4 is significantly down on compression. Their report states that they suspect a roller rocker bearing issue, potentially causing damage to the camshaft or valves, but they don't carry out internal engine repairs.
I'm now looking for an engine specialist. Has anyone experienced this on this engine?


  • Was it the roller rocker?
  • What was the eventual cause?
  • Can anyone recommend a specialist in the Midlands or elsewhere in the UK who has experience rebuilding these engines?
Any advice would be greatly appreciated.
Click to expand...
Sounds like the garage means the rocker arms. Those are prone to failure on the petrol S5's. There should be lots of information about that issue online.
 
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