DIY REPAIR GUIDE — MERCEDES-BENZ C-CLASS, E-CLASS, ML-CLASS, GLK, CLK, R-CLASS AND S-CLAS
Mercedes Camshaft Solenoid Oil Leak
Mercedes M272 V6 and M273 V8 engines have camshaft adjuster solenoids (magnets) on the front of the engine.
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By the Radman Auto Repair team, independent auto repair in Etobicoke since 1999 · Updated November 2026
Mercedes M272 V6 and M273 V8 engines have camshaft adjuster solenoids (magnets) on the front of the engine. Their seals leak oil, and the oil can wick through the wiring harness toward the engine computer. Replacing the solenoids early prevents expensive wiring damage.
Quick answer: If your Mercedes M272 or M273 has oil at the camshaft solenoids or in their connectors, replace the leaking solenoids and clean the connectors. Check the harness for oil; if oil has travelled far up the wiring, the harness may need replacing. Rule out timing parts if you see P0016 or P0017.
At a glance
- Vehicles: Mercedes-Benz C-Class, E-Class, ML-Class, GLK, CLK, R-Class and S-Class with M272 V6 or M273 V8 (about 2005–2011)
- DIY difficulty: Moderate
- Time: about 1.5 hours
- Tools: Torx sockets, trim tools, electrical contact cleaner, shop towels, scan tool
- Parts: camshaft adjuster solenoids, O-rings, electrical contact cleaner
- Codes & warning lights: P0016, P0017, P0011, P0021
- Recalls: check your VIN first; some of these problems are covered by recalls, campaigns or extended warranties
Symptoms
Oil on the solenoids oil at the front of the engine.
Oil in the connector oil in the solenoid connector.
Check engine light cam timing codes.
Rough running rough idle or hesitation.
Oil in the harness oil in the wiring harness.
Burning smell oil on hot parts.
What Causes It
Solenoid seals the internal seals fail with age.
Wicking oil travels through the wiring by capillary action.
Timing parts balance shaft or chain wear can also set P0016.
Before You Start
- Park on level ground, set the parking brake and chock the wheels. Never work under a car held up only by a jack: use rated jack stands.
- Let the engine and exhaust cool before you touch them; coolant systems are under pressure when hot.
- Wear safety glasses and gloves, and disconnect the 12V battery before unplugging electrical parts or working near airbags.
- Check for open recalls on your VIN (Transport Canada or the manufacturer’s site) before you buy parts: a recall repair is free at the dealer.
- Work with the engine cold. Keep oil off the engine computer and wiring.
Step-by-Step: Mercedes Cam Solenoid Leak
- Scan the codes. Read codes and note cam timing codes.
- Inspect the solenoids. The solenoids are on the front of the engine, at the end of each camshaft. Unplug each connector and look inside: oil in the connector or on the pins confirms a leaking solenoid.
- Check the harness. Follow the harness back from the solenoids, unplugging connectors along the way. If oil has reached connectors far from the engine, or the engine computer plug, the harness may need replacing as well.
- Disconnect. Disconnect the battery and unplug the solenoids.
- Remove the solenoids. Remove the Torx bolts and the solenoids.
- Fit new solenoids. Clean the mounting faces, lightly oil the new O-rings, and fit the new solenoids. Tighten the bolts evenly to the torque in the service manual.
- Clean the connectors. Clean the connectors with contact cleaner.
- Clear and test. Clear the codes and test drive.
When to Stop and Bring It In
- Oil has reached the engine computer.
- Codes return after solenoid replacement; check timing parts.
- There is a balance shaft issue on early M272.
- The harness is oil-soaked. See Mercedes-Benz repair.
Not sure, or out of time? Radman Auto Repair in Etobicoke does this repair every week. Book online or call (416) 742-4521.
Also Known As
Owners search for “Mercedes cam solenoid leak”, “M272 camshaft magnet leak”, “Mercedes P0016”, “M273 oil in harness” or “Mercedes oil leak front of engine”. Mercedes calls them camshaft adjuster magnets.
Frequently Asked Questions
Why is oil leaking from my Mercedes cam solenoids?
The internal seals fail with age, so oil leaks past them and into the connectors.
What causes P0016 on a Mercedes?
It can be the solenoids, or timing parts such as the balance shaft on some early M272 engines.
How many solenoids are there?
Usually two on the V6 and four on the V8.
Can I clean the harness?
Light oil can be cleaned, but heavy contamination needs replacement.
How far can the oil travel?
On neglected cars, oil can travel through the wiring harness from the solenoids all the way to the engine computer connector. That is why the leak should be fixed early.
Is there a way to stop oil getting into the harness?
Some owners fit short adapter pigtails between the solenoid and the harness to block wicking. New solenoids with good seals are the main fix.
What is the M272 balance shaft problem?
Some early M272 V6 engines had a balance shaft gear that wore prematurely, setting P0016 and similar codes. It is a major repair, so cam timing codes should be diagnosed properly before replacing parts.
Should I replace all the solenoids at once?
Many owners replace all of them, since they age together. At minimum, replace any solenoid with oil in its connector.
See also Mercedes-Benz Repair & Service, P0011 Camshaft Timing, Check Engine Light Diagnosis, DIY Repair Guides by Manufacturer.
Prefer to Have It Done? Radman Auto Repair, Etobicoke
Independent auto repair in Etobicoke since 1999. We fix what this guide covers, explain what we find, and keep the old parts for you to see.
This Service Includes
✓ Cam timing diagnosis
✓ Solenoid replacement
✓ Harness inspection
✓ Road test