BMW 525i -- May 13th, 2005

Off comes the head! Here there be pistons:

The cylinder walls show very little wear. The hatchmarks from honing are still visible, with only a tiny amount of glazing at the top of the bore, no ring groove, and minor vertical striations toward the bottom of the bore. A bit of emery paper should clean it up like new.

Here's the old head gasket, and the head bolts, and the head bolt washers, and the valve cover gasket, and the valve cover. I'll clean the valve cover. The rest is trash. I can't say for sure (yet), but it appears the head gasket has failed around the oil galley and coolant passages at the intake side of the front of the engine.

Here's the head. Note the carbon build-up on the head and valves. The gasket surface is very gunky. Hopefully, it'll clean up and the head will be straight. I haven't checked it yet. If it's not, it's off to the friendly neighborhood head guy to get it skimmed. I might take it to a head guy anyway, mainly to get the two broken exhaust studs removed and replaced, because I find removing studs and helicoiling to be about as much fun as having teeth drilled without anaesthetic.

If you're a piston, this is what you see:

Here's the camshaft side of the head.

And so on...