A small oil leak can turn into a big repair bill. These spark plugs came out of a Renault Kangoo, and they show exactly what oil in spark plug wells can do: a misfire, and one plug with its centre electrode completely melted away.
The job at a glance
- Vehicle: Renault Kangoo
- Problem: Misfire caused by oil in the spark plug wells
- Root cause: A leaking valve cover gasket
What happened
A leaking valve cover gasket had allowed oil to fill the spark plug wells. Over time, the oil contaminated the ignition system, causing a misfire and excessive heat. The result was one spark plug with its centre electrode melted away, and the others coated in oil.
How does oil get into spark plug wells?
On most modern petrol engines, the spark plugs sit in deep wells or tubes that pass through the valve cover (also called the rocker cover). Two seals keep engine oil out of those wells:
- The valve cover gasket, which seals the cover to the top of the engine
- The spark plug tube seals, which seal around each plug well
Both are made of rubber that hardens and shrinks with age and heat. Once they start leaking, oil seeps into the plug wells and pools around the spark plugs and ignition coils.
What oil in spark plug wells can lead to
What starts as a simple oil leak can quickly lead to:
- Engine misfires
- Damaged ignition coils
- Poor fuel economy
- Loss of power
- Expensive repairs if it’s left too long
Signs to watch for
- The engine running rough, shaking at idle or hesitating when you accelerate
- The check engine light coming on or flashing
- An oil smell under the bonnet, or smoke as oil drips onto hot parts
- Oil on the outside of the valve cover or around the ignition coils
A flashing check engine light usually means a severe misfire. If you see one, reduce your speed and get the car checked as soon as you can.
The proper fix: find the root cause
Replacing the spark plugs alone wouldn’t have fixed this Kangoo. The oil would simply have leaked back in, and the new plugs and coils would have suffered the same fate. A proper repair deals with the leak first: new valve cover and spark plug tube seals, the plug wells cleaned out, and any damaged spark plugs or ignition coils replaced.
At Certified Automotive, we don’t just replace parts. We find and fix the root cause.
Engine running rough on the Gold Coast?
If you’ve noticed your engine running rough, the check engine light is on, or there’s an oil smell under the bonnet, don’t ignore it. Catching these issues early can save you a lot of money. Book your inspection today, or call 0478 499 369. Regular logbook servicing is also a good chance to spot oil leaks before they cause damage.
Need a mobile mechanic on the Gold Coast?
Certified Automotive offers professional Repairs & Diagnostics across the Gold Coast, with mobile mechanics who come to you 7 days a week and a workshop in Mudgeeraba.
We service Mudgeeraba, Robina, Nerang and all Gold Coast suburbs. Call 0478 499 369 for a free quote.
