The 2009 S40 is a compact Volvo with Ford influence in its platform years. The 2.5T turbo five-cylinder is the desirable engine, but automatic transmission cooling failures and PCV system issues plague these cars, often leading to expensive cascading damage if ignored.
Transmission Oil Cooler Failure Leading to Transmission Damage
Common · high severityTypical onset: 80,000-130,000 mi
Symptoms: Pink milkshake fluid in transmission dipstick or expansion tank (coolant mixing with ATF), Transmission slipping, harsh shifts, or limp mode, Overheating transmission temp warnings on dash, Coolant level dropping without visible external leaks
Fix: The internal transmission oil cooler inside the radiator fails, allowing coolant and ATF to cross-contaminate. Requires immediate flush of both systems, new radiator, and if caught late, full transmission rebuild or replacement. Prevention: replace radiator proactively at 100k. Repair: 8-12 hours for trans R&R and rebuild if damaged.
Estimated cost: $3,500-6,500
PCV System Clogging and Oil Sludge (Turbo Models)
Common · high severityTypical onset: 60,000-100,000 mi
Symptoms: Excessive oil consumption (1 qt per 1,000 mi or worse), White smoke from exhaust on startup, Oil in intake tract and intercooler, Check engine light with multiple misfires, Rough idle and loss of power
Fix: The PCV breather box on the back of the block clogs with sludge, causing crankcase pressure to force oil past rings and valve seals. If ignored, leads to piston ring damage requiring engine rebuild. Fix involves replacing entire PCV system including breather box and oil trap, plus cleaning intake. If caught early: 3-4 hours. If rings are damaged: 18-25 hours for short block or engine rebuild.
Estimated cost: $800-1,200 (PCV system only); $4,500-7,500 (if engine rebuild needed)
Angle Gear and Rear Driveshaft Issues (AWD Models)
Occasional · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Clunking or grinding from rear differential area during acceleration, Vibration at highway speeds, AWD warning light illuminated, Metal shavings in angle gear fluid
Fix: The angle gear (transfer case mounted to transmission) develops bearing noise or seal leaks. Rear driveshaft carrier bearing also fails commonly. Angle gear replacement: 5-7 hours. Driveshaft carrier bearing: 2-3 hours. Often both are done together on higher mileage examples.
Estimated cost: $1,800-3,200
Power Steering Hose Leaks and Pump Failure
Common · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Power steering fluid puddles under car (front driver side typically), Whining noise from power steering pump, Heavy steering especially when cold, Low PS fluid warning on dash
Fix: High-pressure power steering hoses develop leaks at crimped ends, and the pump itself can fail from running low on fluid. Subject to recall for certain hose connections. Hose replacement: 2-3 hours due to tight access. Pump replacement adds another 1.5 hours if also needed.
Estimated cost: $600-1,200
Front Control Arm Bushings and Ball Joints
Common · low severityTypical onset: 70,000-120,000 mi
Symptoms: Clunking over bumps from front suspension, Wandering steering or vague feel, Uneven tire wear on inside edges, Alignment won't hold settings
Fix: Front lower control arm bushings crack and ball joints develop play. Volvo sells complete control arms only (no serviceable bushings). Both sides typically done together with alignment. 3-4 hours total plus alignment.
Estimated cost: $800-1,400
Throttle Body Carbon Buildup and Idle Issues
Occasional · low severityTypical onset: 80,000-150,000 mi
Symptoms: Rough idle or hunting idle when warm, Hesitation or stumble on light throttle, Check engine light with throttle position codes, Stalling when coming to a stop
Fix: Electronic throttle body accumulates carbon on the butterfly valve causing erratic idle. Requires removal, cleaning, and ECM relearn procedure. Some cases need new throttle body if motor is worn. 1.5-2 hours labor.
Estimated cost: $250-600
Buy the turbo with a manual transmission if you can find one and verify PCV system maintenance; avoid high-mileage automatics unless transmission and radiator have been recently replaced.
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.