BMW M2: Valve cover and oil filter housing gasket leaks (N55 / S55)

Both engines fitted to the F87 M2 use moulded rubber gaskets at the valve cover and the oil filter housing, and both harden and shrink with heat cycling. The oil filter housing sits above the exhaust side, so a leak there drips onto hot components and produces the burning smell owners notice before they ever see a puddle. Neither is difficult in itself, but the M2 runs a high-viscosity 10W-60 in the S55 and losing oil unnoticed on a performance engine is how a much larger bill starts. Treat these as due maintenance rather than a defect on any M2 now several years old.

• Burning oil smell after a drive, strongest when you open the bonnet
• Dark oily residue down the side or rear of the engine
• Oil level dropping between services
• Smoke or haze from the engine bay when stationary after a run

1. 1

   Open the bonnet after the test drive while everything is hot and simply smell for burning oil — that is the most reliable early sign and needs no tools.

2. 2

   With a phone torch, look along the join between the valve cover and the head for wet, dark residue, and then down the right-hand side of the engine at the oil filter housing for oil trails running down towards the exhaust.

3. 3

   Clean, dry alloy is what you want; a grimy, oil-darkened area is not.

4. 4

   Pull the dipstick and check the level, and ask the seller how much oil the car uses between services and which oil they use — the S55 wants 10W-60 and an owner who does not know that is telling you something.

5. 5

   Look at the ground where the car parks for drips.

6. 6

   If a workshop inspection is possible: have it on a hoist to confirm whether the source is the valve cover, the filter housing or the oil pan, as the three look similar from above.

Parts involved: Rocker / valve cover.

$500 to $1,800 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Have the valve cover or oil filter housing gaskets been replaced?”
• “Which oil does it run, and how often is it changed?”
• “Does it use oil between services?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.