Maserati 4.2L Valve Cover Gasket Failure
Diagnosis, Removal, and Professional Service Considerations
(Wet Sump & Dry Sump Engines)
Common Symptoms & Root Cause
Sitting at a stop light, idling in traffic, or cruising slowly around town, you suddenly notice a strong burnt oil odor entering the cabin through the vents or windows. In some cases, you may even see light smoke rising from the front of the vehicle on cold start.
This is an extremely common issue on Maserati 4.2L engines, both wet sump and dry sump, including:
GranSport
GranTurismo
Coupe / Cambiocorsa
Quattroporte
4200 variants
The cause is almost always aging valve cover gaskets. Over time they begin to seep, then leak, allowing engine oil to drip directly onto the exhaust manifolds. Once hot, the oil burns off, creating persistent odor and occasional smoke.
Under-Vehicle Perspective – What’s Actually Happening
The images above show an under-car perspective of valve cover oil leakage. This particular Maserati had 58,000+ miles at the time of service. Based on condition, it had likely been replaced once before — which further reinforces how common this failure is on the 4.2L platform.
Spark Plug Tube Seals – Often Overlooked, Always Critical
In addition to the perimeter valve cover gasket, each spark plug tube uses its own individual seal. These must be replaced during service.
Oil accumulation inside the spark plug cavities can:
Destroy ignition coils
Cause misfires
Trigger check engine lights
Lead to costly secondary failures
Ignoring these seals is one of the most common mistakes I see during incomplete repairs.
Parts Required – Order Everything First
Where to Start
Before touching the car, order all required components. You will need:
Valve Cover Gaskets
Left: #198927
Right: #198928
Spark Plug Tube Seals – #187706 (x8)
Secondary Air Injection Gaskets – #186781 (x4)
Parts can be sourced from Ricambi, Maserati Parts USA, or OEM suppliers.
Professional Tip:
Replace factory press-style hose clamps with worm-drive clamps. This dramatically improves future serviceability and reduces the risk of hose damage.
Engine Bay Disassembly
Remove all plastic engine bay trim to expose the intake system and valve covers.
Intake, Throttle Body & MAF Removal
Remove the intake tube, throttle body, and MAF assembly. Factory clamps are crimped — use pliers and a flat screwdriver to remove them.
Note:
Wet sump configurations (GranTurismo, later Quattroporte) will vary slightly in layout.
Ignition Coils, Injector Harness & Cam Variator Plug
Spark Plug Coils & Cam Variator Connector
Remove the Maserati-branded harness covers to access:
Ignition coils
Fuel injector harnesses
Cam variator connector
The injector harnesses are factory numbered, eliminating the need for manual labeling.
Important:
Clean every connector and apply dielectric grease before reinstallation.
Secondary Air Injection System – The Most Challenging Step
Secondary Air Injection System
This is the most time-consuming and frustrating portion of the job. The air injection piping physically blocks valve cover removal, and must be carefully loosened and repositioned.
Professional Tips:
Use swivel sockets and long extensions
Replace all secondary air gaskets
Secure tools to your wrist if prone to drops
Take your time — rushing causes scratches
Failure to reseal this system properly will result in secondary air injection fault codes.
Valve Cover Removal & Cleaning
Use plastic trim tools only. No metal-to-metal contact. Protect painted surfaces with painter’s tape if clearance is tight.
Once removed, clean the covers with a soft-bristle brush and mild cleaner such as Simple Green. Avoid pressure washers or harsh solvents.
Reinstallation & Final Notes
Re-installation
Reassembly is the reverse of removal.
I recommend using Permatex Red High-Temp RTV at factory sealing points — do not use fast-setting gasket compounds.
The result is a clean, properly sealed engine — no oil odor, no smoke, and no repeat repairs.
Hello Craig,
Excellent write-up, thank you for your time. I’m curious, do you know the specific differences for the 4.7 engines with auto trans? I’m looking to do this service at home on my 2010 GranTurismo S.
Regards,
Edward
Hello,
Great write-up. You mentioned that you used Permatex Red High Temp RTV gasket maker to supplement the strength of the new OEM gasket. How/where did you apply it?
Jeff you need to apply a thin layer on both the valve cover, including the individual spark plug metal holes the gasket goes over the top of, and, on the gasket that mates head. In all both metal surfaces will have a thin layer of Red.
Any idea on the amount of time it took you to do this job? Just wanting to plan ahead….
Hi Craig, excellent write up but the photos don’t seem to download?, anything to do.
Regards
Stewart.
I am working on a solution please tell me if you can see them now.
Coming through as normal, thanks.