The 2007 Cayenne S with the 4.5L V8 is a capable SUV plagued by catastrophic engine failures due to scored cylinder bores, plus transmission cooling and mount issues that can leave you stranded. Budget heavily for engine work or walk away.
Cylinder Bore Scoring and Catastrophic Engine Failure
Common · high severity
Typical onset: 60,000-120,000 mi
Symptoms: Blue smoke on cold start that clears after warmup, Excessive oil consumption (1 qt per 500-1000 miles), Rough idle when cold, Loss of compression, Eventual bearing failure and complete engine seizure
Fix: The M48 engine suffers from nikasil cylinder liner scoring due to poor piston/bore clearances and sulfur in fuel. No fix short of full engine rebuild with sleeved cylinders or factory short block replacement. Expect 40-60 labor hours for rebuild, 25-35 hours for short block swap. Many owners install LN Engineering Nickies liners or IPD plenum.
Estimated cost: $12,000-22,000
Transmission Oil Cooler Failure and Fluid Cross-Contamination
Common · high severity
Typical onset: 80,000-140,000 mi
Symptoms: Milky or frothy transmission fluid, Coolant loss with no visible leaks, Transmission slipping or harsh shifts, Sweet smell from tailpipe, Overheating transmission
Fix: Internal cooler inside the radiator end tank fails, allowing coolant into ATF and vice versa. Requires radiator replacement, complete transmission flush (often multiple flushes), new filter and pan gasket. If coolant circulated long in trans, internal damage likely. 6-10 hours labor depending on damage assessment.
Estimated cost: $1,800-3,500
Transmission Mount Failure
Common · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: Clunk when shifting from Park to Drive or Reverse, Excessive drivetrain movement felt through cabin, Vibration at idle in gear, Visible tearing or fluid leaking from mount
Fix: Hydraulic transmission mount collapses internally, allowing excessive powertrain movement. Replacement is straightforward but requires supporting transmission. 2-3 hours labor. OEM mount recommended over aftermarket.
Estimated cost: $600-900
Timing Chain Tensioner and Guide Failure
Occasional · high severity
Typical onset: 100,000-150,000 mi
Symptoms: Rattling noise from front of engine on cold start, Check engine light with cam correlation codes, Metallic rattling at idle, Sudden loss of power if chain jumps
Fix: Plastic chain guides wear and tensioners lose pressure, allowing chain slap. Can cause catastrophic valve-to-piston contact if chain jumps. Requires front engine disassembly, all guides, tensioners, and chains replaced. 18-25 hours labor. Often done during bore scoring repair.
Estimated cost: $4,500-7,000
Coolant Pipe and Fitting Leaks
Common · medium severity
Typical onset: 80,000-130,000 mi
Symptoms: Coolant puddles under vehicle, Sweet smell in cabin or engine bay, Overheating or low coolant warnings, Visible green coolant on engine valley or subframe
Fix: Plastic coolant pipes and quick-connect fittings become brittle and crack, especially in engine valley and near firewall. Some require intake manifold removal for access. 3-8 hours depending on location. Replace all suspect pipes preventively once one fails.
Estimated cost: $800-2,200
Air Suspension Compressor and Line Failures
Occasional · medium severity
Typical onset: 90,000-140,000 mi
Symptoms: Vehicle sits low at one corner or all around after sitting, Compressor runs constantly, Suspension fault message on dash, Hissing sound near wheel wells or compressor
Fix: Air struts develop leaks at bellows or fittings, compressor wears out from overwork. Compressor replacement 2-3 hours, single strut 2-3 hours, airlines require body disassembly. Many owners convert to coil springs for $2,000-3,000 to eliminate future issues.
Estimated cost: $1,200-2,800 per corner for strut; $1,800-2,500 for compressor
Owner tips
Have a pre-purchase compression and leak-down test done on every cylinder — bore scoring is when, not if, on these engines
Check transmission fluid color immediately; milky fluid means walk away or budget for transmission replacement
Use quality synthetic oil and change every 5,000 miles religiously to delay bore scoring
Budget $3,000-5,000 annually for unexpected repairs if buying high-mileage
Inspect all coolant hoses and pipes during any engine-out service
Only buy if you can afford a $15,000-20,000 engine replacement or find one with documented fresh rebuild — this is a money pit masquerading as a luxury SUV.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: AGM battery required; located under driver seat or in cargo area; H8 group may also fit as alternative
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Every control module on the 2007 Porsche Cayenne S — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
Transmission Control Unit (TCU)2.5 hr R&Rdealer / factory tool +0.8 hr▸ programming details
📍 Transmission tunnel, center console area, or mounted on transmission
🔧 Porsche PIWIS I or PIWIS II
⚠️ Tiptronic S transmission. Adaptation values must be reset after replacement.
Anti-lock Brake System Control Unit with Porsche Stability Management (ABS/PSM)2.0 hr R&Rdealer / factory tool +0.5 hr▸ programming details
📍 Front left wheel well area, mounted to ABS hydraulic unit
🔧 Porsche PIWIS I or PIWIS II
⚠️ Integrated with PSM. Brake bleeding and system calibration required after replacement.
⚠️ Mileage programming required by dealer. Immobilizer component in some variants.
Kessy Control Unit / Immobilizer (KESSY)1.0 hr R&Rdealer / factory tool +1.5 hr▸ programming details
📍 Dashboard area, near steering column or center console
🔧 Porsche PIWIS I or PIWIS II
⚠️ Key programming and DME pairing required. Keyless entry/start more common in 2007.
Park Assist Control Unit (ParkAssist)0.8 hr R&Raftermarket tool +0.2 hr▸ programming details
📍 Rear cargo area, right side or behind rear bumper
🔧 Durametric or Autel
⚠️ Optional equipment. Sensor calibration may be needed.
Seat Memory Control Unit (Seat Memory)0.8 hr R&Raftermarket tool +0.2 hr▸ programming details
📍 Under driver or passenger seat
🔧 Durametric or Autel
⚠️ Optional equipment. Memory seats and power adjustments.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2007 Porsche Cayenne S 4.5L V8 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.