My 2004 Holden Cruze manual is getting oil in the number two spark plug tube. Where could it be coming from?

Question

Accepted Answer

Like a lot of relatively modern engine designs, the Cruze uses a spark plug centrally located in the cylinder head. That means that it’s between the two camshafts in the Holden’s case, and that means the spark plug lead needs to effectively pass through the rocker cover to attach to the spark plug. In turn, that means that the spark plug sits at the bottom of a tube that forms an oil-tight chamber between the inside of the tube (where the plug lives) and the inside of the rocker cover (which has oil flinging around inside of it when the engine is running).

The problems start when the seal at the bottom of that tube fails and allows oil to seep into the tube from the rocker cover. That’s when you’ll see the oil you described. The fix is to remove the rocker cover and replace either the whole gasket, or the O-ring seal (depending on the design). If it’s the latter, don’t just replace the one that’s leaking now, replace all of them as the rest won’t be far behind the one that’s already leaking. O-rings and gasket start to become hard and brittle as they age, and that’s when leaks will occur. This is not a huge job to fix, but left unchecked, it can allow the engine to begin to misfire.

2004 Holden Cruze	Specs	Price
(base)	Specs: 1.5L, Unleaded Petrol, 4 SPEED AUTOMATIC	Price: $3,190 - $5,060
(base)	Specs: 1.5L, Unleaded Petrol, 5 SPEED MANUAL	Price: $2,200 - $3,410

2004 Holden Cruze Pricing and Specs

All 2004 Holden Cruze pricing and specs

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2004 Holden Cruze Pricing and Specs

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