Join Date: Nov 2013
Location: United Kingdom
County: East Riding of Yorkshire
Is my engine running properly? misfire?
Hi, a bit of oil going down the plug holes won't hurt the engine 'per se' other than causing a bit of smoke (unless it's a LOT and causes a compression lock), But, the rub is, it will also have washed into the affected cylinders any grit that was lurking in the wells And there Will have been some!
Sucking crud out with a gravy sucker is a good idea, but it won't get those particles of grit out from around the base of the plugs!
Ideally the plug bores should Always be blown out with an airline before slackening the plugs, can make a bit of a mess of your makeup if there's a lot down there, but better out of the plug bore than in the cylinder!
Some of the crud that washes (with oil) or falls (as dust) into the cylinder will "Always" get impacted into the valve seats and you Will lose compression - at least temporarily, this is worse on engines with 4 Valves per cylinder than two, because there's more of 'em to leak and being relatively small in diameter are more susceptible to being held off their seats by particles of grit!
So, you will probably notice rough running and a slight misfire, especially when you first started the engine, but a good blast down the road should improve things (don't blame me if your cam belt snaps) if it doesn't, have a compression check done, this will confirm the problem cylinder(s) and if the compressions are low, then a valve grind is the Only remedy unless you can live with it, but if the leak is bad enough, it will show up on a HC meter, and may fail an MOT test if the hydrocarbon emissions are high enough!!