According to Au7o's analysis of 3,180+ owner reports, the 2012 Volvo S40 has 2 documented known issues, with 2 rated critical. The most serious are PCV System Failure Causing Oil Leaks and Engine Damage ($300-$1,500 repair) and T5 Turbocharger Failure from Oil Starvation ($1,200-$3,500 repair). The most commonly reported issue is PCV System Failure Causing Oil Leaks and Engine Damage with 2,200 owner reports. Across all issues with published estimates, repair costs range from $300 to $3,500. DIY maintenance guides at au7o.io.
On the 2004-2012 Volvo S40 2.5L T5, the PCV (positive crankcase ventilation) system on the S40/V50 2.5L T5 engine is a well-known failure point. The system uses a complex oil separator and breather box that clogs with oil sludge, causing excessive crankcase pressure. This pressure forces oil past every seal in the engine - rear main seal, valve cover gaskets, oil filter housing, and turbo seals. Left unchecked, the crankcase overpressure can push the rear main seal out, causing catastrophic oil loss. The PCV system should be treated as a maintenance item on these engines. The issue affects all P1 platform Volvos including S40, V50, C30, and C70.
Common Symptoms
Oil leaks from multiple locations simultaneously
Rough idle and misfires
Whistling noise from engine bay (vacuum leak through PCV)
Check engine light with lean codes (P0171)
Oil pooling on top of transmission (rear main seal leak)
White smoke from exhaust (oil in intake)
How to Fix
Replace the entire PCV system including oil trap/separator (Volvo part 31338023), breather hoses, and PCV valve. This is a $100-200 parts job but 3-4 hours labor due to the system's location behind the intake manifold. Replace any damaged seals (rear main seal, valve cover gasket) that leaked due to excessive pressure. Clean intake manifold of oil deposits. Prevention: replace PCV system every 80,000-100,000 miles. Use an OEM or Mann+Hummel PCV unit - cheap aftermarket units fail quickly.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
IPD 140064 early non-PTC P1 oil-separator diaphragm
replace a confirmed torn diaphragm in a serviceable early non-PTC oil-filter-housing separator Fitment/availability: 2004.5-2005 P1 Volvo S40 five-cylinder through engine serial 3285661 with the original non-PTC oil-separator box; inspec…
IPD 142641 later PTC-style P1 five-cylinder PCV diaphragm, cap and spring kit
replace a confirmed torn diaphragm in a serviceable later PTC-style oil-filter-housing separator Fitment/availability: 2006-up P1 Volvo S40 2.4i/T5 and 2004.5-2005 from engine serial 3285662 or an earlier car updated to the PTC-style hou…
High Confidence2,200 owner reportsLast reported by owners Feb 2026Reviewed Feb 2026
Community reported
980 owners
On the 2004-2012 Volvo S40, the Mitsubishi TD04L-14T turbocharger on the S40/V50 T5 fails prematurely when oil supply is restricted. The most common cause is a clogged PCV system (which back-pressures the oil return line), deteriorated oil feed line banjo bolt screens, or extended oil change intervals allowing sludge to form. The turbo bearings wear without adequate lubrication, causing shaft play that leads to oil leaking past the compressor seal (blue smoke) and eventual catastrophic failure. Many owners don't realize the PCV system failure is the root cause of their turbo failure.
Common Symptoms
Blue or white smoke from exhaust, especially under boost
Excessive turbo shaft play (visible wobble in compressor wheel)
Oil consumption increasing rapidly
Whining or grinding noise from turbo area
Loss of boost pressure
Oil in intercooler piping
How to Fix
Replace turbocharger (OEM Mitsubishi TD04L-14T, Volvo part 36002369, or BorgWarner aftermarket equivalent). CRITICAL: Replace the PCV system simultaneously - a new turbo will fail again quickly if the PCV system is still clogged. Replace the turbo oil feed line and banjo bolt screen. Flush intercooler and piping to remove oil residue. Use quality 5W-30 synthetic oil and change every 5,000 miles. Allow turbo to cool at idle for 30 seconds before shutting off after spirited driving.
High Confidence980 owner reportsLast reported by owners Feb 2026Reviewed Feb 2026
NHTSA Recalls4 recalls
STRUCTURE:FRAME AND MEMBERS
VOLVO IS RECALLING CERTAIN MODEL YEAR 2011 S40 PASSENGER VEHICLES. A CRACK ON THE TOP SIDE OF THE PASSENGER SIDE SUPPORT MEMBER IN THE ENGINE COMPARTMENT MAY HAVE DEVELOPED DURING THE FORMING PROCESS IN COMPONENT PRODUCTION.
Campaign #11V18600018/03/2011
SEATS
VOLVO IS RECALLING CERTAIN PASSENGER VEHICLES EQUIPPED WITH POWER FRONT PASSENGER SEATS. THE FRONT SEAT RAIL'S DETECTION SYSTEM WAS MANUFACTURED INCORRECTLY AND MAY PERMIT THE PASSENGER TO FORWARD THE SEAT BEYOND THE INTENDED MAXIMUM.
Campaign #10V59100022/11/2010
STEERING:HYDRAULIC POWER ASSIST:HOSE, PIPING, AND CONNECTIONS
VOLVO IS RECALLING MY 2008-2009 VEHICLES. A SECTION OF THE POWER STEERING RETURN LINE HOSE WAS NOT PROPERLY VULCANIZED (CURED) AND DOES NOT MEET SPECIFICATIONS. IF THE POWER STEERING RETURN HOSE FAILS, A SUDDEN RUPTURE OF THE HOSE CAN OCCUR.
VOLVO IS RECALLING CERTAIN VEHICLES EQUIPPED WITH GARMIN 760 PORTABLE GLOBAL POSITIONING SYSTEM (GPS) UNITS BECAUSE THE BATTERIES ON THOSE UNITS MAY OVERHEAT.
Campaign #10V56600008/11/2010
Enter your VIN at NHTSA.gov to check recalls specific to your vehicle.
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According to Au7o's analysis of 3,180+ owner reports, the 2012 Volvo S40 has 2 documented issues. The most frequently reported are: PCV System Failure Causing Oil Leaks and Engine Damage, T5 Turbocharger Failure from Oil Starvation. Of these, 2 are rated critical and should be addressed promptly.
Is the Volvo S40 reliable?
The 2012 Volvo S40 has 2 known issues documented across 3,180+ owner reports. 2 issues are rated critical: PCV System Failure Causing Oil Leaks and Engine Damage and T5 Turbocharger Failure from Oil Starvation. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
How much does it cost to fix common Volvo S40 problems?
Repair costs for known Volvo S40 issues range from $300 to $3,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, PCV System Failure Causing Oil Leaks and Engine Damage, typically costs $300-$1,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 2004-2012 Volvo S40 PCV System Failure Causing Oil Leaks and Engine Damage?
The PCV (positive crankcase ventilation) system on the S40/V50 2.5L T5 engine is a well-known failure point. The system uses a complex oil separator and breather box that clogs with oil sludge, causing excessive crankcase pressure. This pressure forces oil past every seal in the… Repairs typically run $300-$1,500. Severity: high.
What is the 2004-2012 Volvo S40 T5 Turbocharger Failure from Oil Starvation?
The Mitsubishi TD04L-14T turbocharger on the S40/V50 T5 fails prematurely when oil supply is restricted. The most common cause is a clogged PCV system (which back-pressures the oil return line), deteriorated oil feed line banjo bolt screens, or extended oil change intervals allow… Repairs typically run $1,200-$3,500. Severity: high.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.
