Symptoms
Oil on the coil packs, plug leads and the top of the exhaust manifolds; a burning smell after a drive; in bad cases oil reaching the plugs and causing misfires. Breather hoses on the same engine family crack and leak too, so leaks around the covers aren’t always the gaskets.
The fix, step by step
- Remove the intake ducting, then the coil packs and plug leads (label them — the M113 runs two plugs per cylinder), then the cover bolts.
- Lift the covers, clean every trace of old gasket and sealant, and fit new gaskets plus the bolt grommets.
- Replace the crankcase breather hoses at the same time; where sealant is specified, owners report a continuous bead with no gaps and spotless surfaces is what stops repeat leaks.
- Torque the cover bolts evenly to the factory figure — overtightening distorts the covers.
Tools & part numbers
- Sockets and Torx bits
- torque wrench (low range)
- plastic scraper and brake cleaner
- valve cover gaskets and bolt grommets (genuine or Elring — owners report aftermarket gaskets leaking)
- breather hoses
- Mercedes-approved sealant where called for
Where to buy the parts
URO comprehensive M113 valve cover gasket kitFCP Euro ↗Amazon ↗
Elring valve cover gasket, left (113 016 02 21)FCP Euro ↗Amazon ↗
Elring valve cover gasket, right (113 016 03 21)FCP Euro ↗Amazon ↗
M112/M113 breather cover reseal kitFCP Euro ↗Amazon ↗
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Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.