Experiencing smoke on startup and noticing increased oil consumption in your 2007 Audi S4 Engine? You’re not alone. Many Audi S4 owners, particularly those with the B7 generation and the 4.2-liter V8 engine, encounter similar issues. Let’s delve into a recent case of diagnosing these problems in a 2007 Audi S4.
The Mystery of the Vanishing Oil: Investigating a 2007 Audi S4 Engine
The owner of this particular 2007 Audi S4, boasting just over 68,000 miles and meticulously maintained since 30,000 miles, began noticing smoke upon starting the engine. This symptom was accompanied by a concerning increase in oil consumption, although the engine ran strong during driving. To get to the bottom of this, a compression test was performed.
Compression Test Results: Unveiling Potential 2007 Audi S4 Engine Issues
The compression test results, while not catastrophic, were less than ideal for an engine with relatively low mileage:
- Cylinder #1: 140 psi
- Cylinder #2: 145 psi
- Cylinder #3: 140 psi
- Cylinder #4: 145 psi
- Cylinder #5: 150 psi
- Cylinder #6: 150 psi
- Cylinder #7: 160 psi
- Cylinder #8: 165 psi
These numbers reveal a noticeable variance between cylinders, with cylinders #7 and #8 showing significantly higher compression than others. While experts suggest that warped cylinder walls could be a possibility, maintaining consistent oil change intervals might mitigate further compression decline. Adding to the concern, spark plugs from cylinders #3 and #8 showed signs of oil fouling.
Valve Guides or Valve Stem Seals: Pinpointing the Source of the Smoke
The presence of oil on the spark plugs, combined with the smoke on startup and oil consumption, strongly suggests issues with the valve guides or valve stem seals within the 2007 Audi S4 engine. These components are crucial for preventing oil from leaking into the combustion chamber.
Engine Removal and Intake Valve Inspection: A Deeper Dive into the 4.2 V8
To further investigate, the engine removal process was initiated. Prior to pulling the engine, the intake manifold was removed to prevent damage. A visual inspection of the intake valves provided further clues, revealing oil accumulation on the tops of valves in cylinders #3 and #8 – reinforcing the suspicion of valve seal or guide problems. Interestingly, while most valves appeared clean, some exhibited carbon buildup near the valve seats, which could potentially contribute to the lower compression readings.
Next Steps in Diagnosing the 2007 Audi S4 Engine
With the engine nearing complete removal, a more thorough examination is planned. Disassembly of the engine will allow for a detailed inspection of the valve guides, valve stem seals, and cylinder walls. This hands-on approach is crucial for accurately diagnosing the root cause of the smoke and oil consumption in this 2007 Audi S4 engine and determining the necessary repairs. Stay tuned for further updates as the investigation progresses.
