997driver

I wanted to make this post for future reference in case anyone ever has similar symptoms or finds themselves in this situation.

Background: Purchased a 2015 Macan S in November 17' , Porsche CPO with 52,850 miles. Car was owned and operated in Southern California it's entire life, so it wasn't subjected to extreme cold temperatures. All service records were included and the car was always serviced on time at the local Porsche dealership here in LA.

One week later with 53k miles the car shut down with all the warning lights. Turned out to be fouled spark plugs. Dealership replaced all spark plugs. After that, I got the Oil refill light every 400-500 miles. Brought the car to the dealer every time for them to do an Oil Measurement and refill for their records. After the 3rd reading I left the car there for a diagnosis.

After using a Borescope, it was discovered that Cylinder #5 has scoring along with a fouled-up spark plug. Engine replacement will be needed. Narrative was sent to Porsche HQ for approval. Will update thread as updates come.

user 72902

Petza914

This is disappointing news. Seems live there isn't a recent generation of Porsche vehicle that isn't subject to the possibility of bore scoring. Happens in the 996s, 997s, 991s, the 955, 957, & 958 Cayennes and Panameras that use the same motors, and now the Macan. It's usually more prevalent in colder climate cars so surprising to hear that this first Macan I'm aware of was a So Cal car - maybe it spent a lot of time at ski areas.

I need to do a little research as I have a thought - maybe the tolerances are so tight in the motors to keep compression high for performance that they're just too tight. Usually compression in forced induction motors is lowered to prevent detonation, and I'm wondering if scoring tends to happen more in the NA motors than the Turbo motors. Is a '15 Macan S a LPT motor or a NA motor and if it's a NA motor, when did Porsche change to turbo charging all of the Macan motors, not just the "Turbo" model?

Glad you were CPO and will get this resolved on their $ instead of yours. I need to

Mark in Baltimore

Really sorry to hear this. Was already subscribed to your thread on Macanforum.

Jake Raby said it could also be due to extended warm up times where the fuel system is dumping excess fuel to light up the cats, thereby washing oil off of the cylinders. I get situated in my car, hit the garage door opener, start the car and pull out as soon as the door is fully open.

Petza914

Yup, people who let their cars warm up for 10 minutes in the morning or while they're sitting someplace really have no idea the damage their doing to the motors or cats, but again, most don't car when they replace their minivans and Tahoes. Unfortunately, in the used car market, we have no idea how these POs treated or took care of their cars and extensive PPIs are about all we can do before taking on stewardship of these fine cars.

Mark in Baltimore

I didn't realize idling was bad for Porsche engines. Are there threads on this subject? This is the only one I could find: https://rennlist.com/forums/964-foru...long-time.html (see last two posts)

997driver

Petza914

Stationary idling is bad for all engines, not just Porsche ones. Warm-up idling is the worst as that nice bark you hear when you first start your car is because of an enriched mixture that's used to dump excess fuel into the cats to bring them up to temperature sooner and reduce emissions faster. This enrichment is what Jake was referring to as the extra fuel dumped into the cylinders dilutes the oil and can wash the lubrication from the cylinder walls, contributing to bore scoring that's sometimes seen. When you start the car and drive off, it's still running in an enriched mode, but the extra load on the motor from driving is actually using that extra fuel and the pistons are moving faster so it negates the effect by moving the oil around quicker in the combustion chamber. Idling when warmed up is bad also, as the cats need some air flowing past them to cool efficiently. There are actually some instances of vehicles catching on fire from the catalytic converters overheating - "just google car fire from idling" and you'll get some hits.

The remote start feature, though handy, is a terrible thing for a motor. I love it on my rental cars, especially when on a trip somewhere really cold like MN. I park with the car outside my window and can warm it up before even leaving my room, but no way I'm doing that on cars I own - sorry next owner of my rentals.

Mark in Baltimore

Pete, thanks! Does warm idling contribute to bore scoring?

Petza914

If it does to some extent, it's not nearly as much as start up idling because the mixture isn't enriched. That's more problematic for the cats.

KM1959

Great. As if it wasn't bad enough just sitting in LA traffic, now I have to worry about scoring my cylinders too? Good thing I don't have to commute!

user 72902

I would think it is detrimental since oil pressure is reduced at low rpms.

Mark in Baltimore

Thanks, guys. Not convinced that warm idling contributes to bore scoring, but my mind is open. I understand cats can be affected by temps that are too high.

user 72902

997driver