My son's S60 turbo (it's the one with the larger engine, high-pressure turbo, 265hp) started running rough on Saturday. He ended up driving it 90 miles home. It was rainy weather so I just figured something was wet. On Sunday morning I discovered that the #3 spark plug was loose in the hole and when I removed it, both electrodes were missing. Went to the parts store and got a single plug, and it ran fine after installation. Engine runs and sounds fine. What potential damage should we be looking for? Should he take it to the dealer for evaluation? Thanks.

Do you think the plug got loose first or the electrodes broke first? Some people have been concerned about certain brands of plugs losing electrodes. Is there a consensus on how likely this is, and with which plugs? Do you know what type of plug it was you had in there?

I don't really know which occurred first. It was a dealer-installed Volvo plug.
Marlin

Just for piece of mind, I would buy 5 new plugs, OEM, and replace them all. The multi-electrode plugs have been known to kill valves because they break off and get stuck in the valve opening.
Consider yourself very lucky,

Klaus
--
1975 164 w/174,800mi (Sold) 1995 850T w/91,000mi, 1998 V70R w/129,000mi

Tough to call. If the engine is running ok you are fortunate. Usually when an electrode goes it messes up a valve. Perhaps this one just exited without damaging anything. This is my take only.

dick

Dick pretty much called it as it is. If it runs ok then count your blessings and move on. Aside from a bore scope to go in there and look around your only other option is to pull the head and have a look see and who the heck wants to do that if it is running fine!?! I have seen them imbed the electrode in the piston face and keep running ok but let's hope that your's passed harmlessly out the exhaust port.

mark

Would the electrode passing out the exhaust port, then going through the turbo cause any damage there?
Marlin

Doubtful. It it did the turbo would lose boost or be noisy.

dick