[1897]

Anyone familiar with this corrosion around and in the spark plug wells? Some of it looks like aluminum oxide. Two of the wells had pretty extensive corrosion in the well itself, four were clean inside but had corrosion outside. Some indication of oil leaking from the valve cover but I don't think that would cause the corrosion.

Recently bought 2011 335xi with 110k miles with mods and MHD stage 2. Runs great but some gasoline smell through the air vents. Pulled plugs to check if they were tight and re-torqued.

[Brandoch]

I have nothing to add except for eww, and wow.

[relative4]

Something yucky got spilled.

[JM98]

gross. Winter car? Cowl delete or missing engine cover can contribute to excessive corrosion like that.

[Finngo]

Originally Posted by JM98

gross. Winter car? Cowl delete or missing engine cover can contribute to excessive corrosion like that.

+1

[mecheng77]

Your 2nd shows some bad corrosion. Was it a flood vehicle?
I would spray it with wd40 and try to clean up the corrosion with a rag or brush except for spark plug wells, for that just spray

[SlimE92]

Originally Posted by JM98

gross. Winter car? Cowl delete or missing engine cover can contribute to excessive corrosion like that.

Fake news...

I've been running with no cowl and bms cowl filters for a few years and have absolutely no rusting/corrosion.

[TunafishE93]

There's been many reports of water in the 5/6 plug well with the cowl deletes so the statement is justified. But glad "you" don't have a problem.

[SlimE92]

Originally Posted by TunafishE93

There's been many reports of water in the 5/6 plug well with the cowl deletes so the statement is justified. But glad "you" don't have a problem.

I've only seen one other case and it was speculated that he didn't have the engine cover on

[K9Leader]

I had left the beauty cover off for several months on my 2010 E91 after I bought it two years ago. When I did the 3IM upgrade last year I found water in wells 5 &6. I also saw that a previous owner had done the valve cover gasket (good!) But had cut a notch out of the cowl to do so (bad!) That notch and no beauty cover resulted in the water. I patched the notch and will keep the beauty cover on from now on.

[SlimE92]

Originally Posted by K9Leader

I had left the beauty cover off for several months on my 2010 E91 after I bought it two years ago. When I did the 3IM upgrade last year I found water in wells 5 &6. I also saw that a previous owner had done the valve cover gasket (good!) But had cut a notch out of the cowl to do so (bad!) That notch and no beauty cover resulted in the water. I patched the notch and will keep the beauty cover on from now on.

Moral of the story is cowl delete is fine if you keep the engine cover on.

Known fact for years...

[1897]

Thanks for your ideas. Cowl and engine cover were on when I bought the car, attached properly and in good shape (better than the corrosion would imply). Possible someone had removed the covers in the past or didn't have them installed correctly and water got in. In general the car is relatively clean but with some age appropriate "grime". Runs great and no indications it was a flood car.

Not the easiest area to clean so may wait until I replace the valve cover gasket and have all the wiring and fuel rails out of the way.

[TunafishE93]

Is it only the 5/6 cylinder well shown or are all wells like that? That would at least tell you if it was flooded (all wells) or only 5/6 than cowl delete. Spray some wd40 will prevent further corrosion until can be cleaned up.

[TheMidnightNarwhal]

Originally Posted by JM98

gross. Winter car? Cowl delete or missing engine cover can contribute to excessive corrosion like that.

Winter car would not cause this at all.

[TheMidnightNarwhal]

Originally Posted by TunafishE93

There's been many reports of water in the 5/6 plug well with the cowl deletes so the statement is justified. But glad "you" don't have a problem.

True, having no cowl or engine cover is honestly kinda dumb IMO. It helps alot to direct water away from the top of the head.

[1897]

Originally Posted by TunafishE93

Is it only the 5/6 cylinder well shown or are all wells like that? That would at least tell you if it was flooded (all wells) or only 5/6 than cowl delete. Spray some wd40 will prevent further corrosion until can be cleaned up.

Only 5/6 had corrosion in the spark plug well. There was some minor corrosion outside of 1-4 wells but not in the wells themselves. Will WD-40 "dissolve" aluminum corrosion?

[tlow98]

Haven't ever seen the titanic in this high resolution!

[clegg]

The WD-40 won't necessarily dissolve the corrosion, but possibly prevent it from getting worse until it can be removed. Aluminum Jelly may work to lessen the damage.

I wonder if that is a replacement engine that may have been sitting around that's in there?

[Gamb1t]

Did you park it at a beach overnight during high tide? Wow.... How's the entire engine bay?

[1897]

Originally Posted by Gamb1t

Did you park it at a beach overnight during high tide? Wow.... How's the entire engine bay?

Engine and engine bay are in good shape (modest grime and oil seepage). Probably will replace valve cover and gasket but not too bad.

[1897]

Originally Posted by clegg

The WD-40 won't necessarily dissolve the corrosion, but possibly prevent it from getting worse until it can be removed. Aluminum Jelly may work to lessen the damage.

I wonder if that is a replacement engine that may have been sitting around that's in there?

Interesting possibility. Rest of engine looks "normal" though. Assume BMW dealer will be able to check if engine was original.