2017 PORSCHE CAYENNE S E-HYBRID

Typical onset: 60,000-100,000 mi

Symptoms: Coolant loss with no visible external leaks, White smoke from exhaust on cold start, Rough idle and misfires, especially cylinder 2 or 5, Metal shavings in oil, elevated oil consumption (1 qt per 1,000 mi or more)

Fix: The supercharged 3.0L suffers from poorly designed internal coolant pipes that crack and leak into cylinders, plus cylinder liner issues causing bore scoring. Repair requires full engine rebuild or short block replacement. Figure 40-60 hours labor depending on whether you rebuild in-chassis or pull the engine. Many shops opt for factory remanufactured short block to avoid liability.

Estimated cost: $15,000-25,000

Typical onset: 80,000-120,000 mi

Symptoms: Reduced electric-only range (below 8-10 miles when new was 14 miles), Battery warning light or hybrid system malfunction message, Inability to charge or hold charge, Increased engine run time even with full battery

Fix: The 10.8 kWh lithium-ion battery pack degrades over time, especially if car sat unused or was frequently fast-charged. Porsche only sells the complete assembly, not individual modules. Replacement is 8-12 hours labor to remove rear cargo floor, disconnect high-voltage interlock, and swap unit. Some indie shops now offer cell-level refurbishment for $4K-6K.

Estimated cost: $8,000-12,000

Typical onset: 70,000-110,000 mi

Symptoms: Transmission fluid in coolant reservoir (strawberry milkshake appearance), Coolant in transmission pan, Harsh shifting or slipping, Overheating transmission or engine

Fix: The 8-speed Tiptronic S shares coolant and transmission fluid through an internal heat exchanger that fails and cross-contaminates. This kills the transmission if not caught early. Requires transmission removal, full flush of both systems, cooler replacement, and often transmission rebuild if fluid mixing occurred. 16-24 hours labor depending on transmission condition.

Estimated cost: $4,500-9,000

Typical onset: 60,000-90,000 mi

Symptoms: Clunk or thud when shifting from Park to Drive or Reverse, Vibration at idle, especially with A/C on, Excessive engine movement visible when accelerating hard

Fix: The added weight of the hybrid system accelerates wear on the hydraulic engine and transmission mounts. The trans mount is the usual first failure. Replace both trans and engine mounts as a set—they're a 4-6 hour job with the car on a lift and motor supported. OE Porsche mounts only; aftermarket versions fail quickly.

Estimated cost: $1,200-2,000

Symptoms: Rough running or hesitation under load when hybrid battery depleted, Check engine light with lean fuel trim codes (P0171/P0174), Hard starting after sitting, Limp mode when demanding full power

Fix: The in-tank fuel pump assembly has an integrated filter that clogs prematurely, especially with ethanol fuel. Porsche doesn't sell the filter separately—whole pump assembly required. Tank must be dropped, 3-5 hours labor. This isn't recalled but should've been given the failure rate.

Estimated cost: $1,500-2,200

Typical onset: 50,000-80,000 mi

Symptoms: Coolant smell in cabin or near front of engine bay, Visible coolant seepage at tank seams, Low coolant warning light, Overheating if level drops significantly

Fix: The plastic expansion tank develops stress cracks at mounting points and seams, especially in hot climates. Given the engine's sensitivity to coolant loss (see bore scoring above), this is critical. Easy 1-2 hour DIY job, but use only OEM tank—aftermarket versions fail within a year. Replace the cap and any suspect hoses at the same time.

Estimated cost: $400-700