1978 Porsche 911 Problems: 4 Known Issues
1978 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated October 2026
According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1978 Porsche 911 has 4 documented known issues, with 1 rated critical. The most serious is Timing chain tensioner collapse on pre-1984 cars destroys the engine ($700-$1,800 repair). Across all issues with published estimates, repair costs range from $60 to $4,500. DIY maintenance guides at au7o.io.
1978 · All trims · All engines
Choose the year and equipment for your written issues and visual request.
No email neededHow interest is saved
Interest applies to the selected vehicle and configuration; it is not a reservation. Voting stores a first-party identifier for up to 180 days to prevent repeat votes. No account or email is needed. Clearing cookies or using another device may count separately. Privacy
Visual coming soon
Your interest helps us choose what to build next.
Visual Known Issues · Coming soon
$4.99/month plus taxes at launch · No payment today
All 4 Known Issues
NHTSA Recalls6 recalls
FUEL SYSTEM, GASOLINE:DELIVERY:HOSES, LINES/PIPING, AND FITTINGS
DUE TO ROUTING OF FUEL LINE FROM THE FUEL TANK TO REAR FUEL PUMP, THE FUEL LINE MAY BE DAMAGED UNDER CERTAIN DRIVING CONDITIONS. ON FULL TRAVEL OF LEFT REAR SUSPENSION (JOUNCE), THE BRACKET FOR THE BRAKE PAD WEAR INDICATOR WIRE ON LEFT REAR CONTROL ARM COULD CONTACT AND DAMAGE FUEL LINE.
ELECTRICAL SYSTEM:WIRING:FUSES AND CIRCUIT BREAKERS
AFTER THE ENGINE HAS BEEN TURNED OFF, THE REAR HEATER WILL AUTOMATICALLY OPERATE IN ORDER TO DISSIPATE HEAT IN THE ENGINE HEATING SYSTEM. DURING THIS OPERATION, THE RESISTOR FOR THE REAR HEATER BLOWER CAN BECOME OVERLOADED DUE TO A BINDING OR SEIZED REAR HEATER BLOWER.
SEAT BELTS:FRONT:RETRACTOR
THE REAR SEAT BELTS DO NOT INCLUDE EMERGENCY-LOCKING OR AUTOMATIC-LOCKING RETRACTORS. THE BELTS DO NOT COMPLY WITH FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 208, "OCCUPANT CRASH PROTECTION".
STEERING: STEERING WHEEL/HANDLE BAR
A PART OF THE STEERING COLUMN UPPER UNIVERSAL JOINT CRACKED DURING THE MANUFACTURING PROCESS.
VEHICLE SPEED CONTROL
THE BALL SOCKETS ON THE CRUISE CONTROL LINKAGE CAN BREAK, ALLOWING THE CRUISE CONTROL LINKAGE TO BECOME DETACHED ON ONE END AND JAM ON NEARBY COMPONENTS, WHICH COULD IMPAIR THROTTLE PLATE OPERATION.
+ 1 more recalls. Check all on NHTSA.gov
Enter your VIN at NHTSA.gov to check recalls specific to your vehicle.
Join 600+ people using Au7o to better understand their vehicles.
Don't see your problem? Describe your symptoms to get a diagnosis, or get a full repair guide.
Other Porsche Models
Frequently Asked Questions
What are the most common Porsche 911 problems?
According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1978 Porsche 911 has 4 documented issues. The most frequently reported are: Timing chain tensioner collapse on pre-1984 cars destroys the engine, 915 gearbox worn 2nd-gear synchros and rounded dog teeth, Chronic oil leaks from cooler lines, thermostat seal and chain housings. Of these, 1 is rated critical and should be addressed promptly.
Is the Porsche 911 reliable?
The 1978 Porsche 911 has 4 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 1 issue is rated critical: Timing chain tensioner collapse on pre-1984 cars destroys the engine. 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 Porsche 911 problems?
Repair costs for known Porsche 911 issues range from $60 to $4,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Timing chain tensioner collapse on pre-1984 cars destroys the engine, typically costs $700-$1,800 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 1965-1983 Porsche 911 Timing chain tensioner collapse on pre-1984 cars destroys the engine?
Every 911 built through 1983 uses spring-loaded mechanical cam chain tensioners that lose their hydraulic damping oil and collapse with age and heat cycling. When a tensioner fails the slack timing chain jumps a tooth (or off the sprocket entirely), the cams lose sync with the cr… Repairs typically run $700-$1,800. Severity: high.
What is the 1972-1986 Porsche 911 915 gearbox worn 2nd-gear synchros and rounded dog teeth?
The 915 transmission (1972-86, replacing the earlier 901) is the air-cooled 911's known shifting weak point. Its Porsche-style synchros wear, and second gear in particular suffers — the synchro ring loses its bite and the engagement 'dog teeth' get rounded off (or snapped if some… Repairs typically run $1,500-$4,500. Severity: medium.
What is the 1965-1989 Porsche 911 Chronic oil leaks from cooler lines, thermostat seal and chain housings?
Air-cooled 911s carry oil all around the car through an external dry-sump system, and after decades the seals and hoses leak everywhere. The classic offenders are the two short rubber crimp hoses joining the hard lines to the front-fender oil cooler (they crack and weep), the oil… Repairs typically run $300-$2,500. Severity: medium.
What is the 1973-1983 Porsche 911 CIS airbox blows apart from an intake backfire?
1973-83 normally-aspirated 911s with Bosch CIS (K-Jetronic / 'Continuous Injection System') use a large molded plastic airbox between the throttle body and intake runners. A lean or ill-timed condition causes an intake backfire, and that small explosion pressurizes the sealed air… Repairs typically run $60-$1,200. Severity: medium.
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.