Oil spots under your 2019 Infiniti Q70 and the smell of burning oil from the engine bay typically point to a common maintenance item—valve cover gasket failure. The Q70's VQ37VHR 3.7L V6 (or VQ35HR on some models) uses rubber gaskets that deteriorate over time, and understanding this failure helps plan appropriate repairs.
Understanding Valve Cover Gaskets
The valve covers seal the top of the cylinder heads, containing the oil that lubricates the valvetrain. Rubber gaskets between covers and heads prevent oil escape. Heat cycling over thousands of miles causes these rubber gaskets to harden, shrink, and crack, eventually allowing oil to seep past.
Symptoms of Valve Cover Leaks
- Oil visible on the engine's exterior, particularly at cover edges
- Burning oil smell, especially after parking or on hot days
- Smoke from engine bay when oil contacts hot exhaust
- Low oil level between changes
- Oil accumulation in spark plug wells
- Possible misfires if oil fouls spark plug connections
Why the V6 Configuration Matters
The VQ-series V6 has two valve covers—one for each cylinder bank. Leaks can develop in one or both. The rear bank cover is against the firewall, requiring more labor to access than the front bank.
Related Issues
Spark Plug Tube Seals
These seals prevent oil from entering the spark plug wells. They're integral to or accompany the valve cover gaskets and should be replaced simultaneously.
PCV Valve
A stuck PCV valve can increase crankcase pressure, forcing oil past otherwise adequate gaskets. Inspection is warranted when addressing leaks.
Repair Costs
| Repair | Parts | Labor | Total |
|---|---|---|---|
| Front valve cover gasket | $50-$100 | $200-$350 | $250-$450 |
| Rear valve cover gasket | $50-$100 | $300-$500 | $350-$600 |
| Both valve cover gaskets | $100-$200 | $400-$700 | $500-$900 |
| Spark plug tube seals (included) | $20-$50 | Included | $20-$50 additional |
Repair Strategy
If one side is leaking, consider replacing both gaskets. The labor overlap makes addressing both sides cost-effective, and if one gasket has failed, the other is likely approaching similar condition.