So I've tried cleaning the engine 5 or 6 times with progressively more aggressive chemicals. Today I finally tried that purple bottle of SuperClean. It said to avoid prolonged contact with aluminum so I washed it off in less than 4 minutes (the car wash I used has a timer).

Guess what turned white, cloudy, chalky, milky... whatever you want to call it.

Is this serious damage? Would spraying AMSoil Metal Protectant on it prevent evil things from happening? What now, basically?

I guess some good came of it. I can finally see the engine. Before there were millimeters of built up grease. It used to be so bad that I actually started out this long quest by scraping it off with a spoon. So from one extreme to another...

Any insight or advice much appreciated!

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1983 300TD 240k Thistle Green Auto (Euro) [sold]
1984 300D 240k Petrol Green Auto
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"You know, times are changing. Ladies can do stuff now and you're going to have to learn how to deal with it."
"What? Were you saying something? Look, I don't speak Spanish."

Pictures would be nice. The metal you're trying to clean may be an alloy of several metals; it depends on the car and what part of the engine. The two cars in your signature have cast iron blocks/heads with an alloy valve cover.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

superclean is really aggressive. Not sure what is in it, but basically you have eched it. I tend to prefer steam cleaning(not pressure washing) and only pre soak with simple green. Amsoil metal protectant will get washed off with heavy duty cleaning, so no it would not have helped. trying it now most likely will not help either. More then likely you will need to buff the aluminum parts on a buffing wheel to restore them. You could try try a "mothers" polishing ball and some compound, then if that will not do it then buffing.

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1977 240D turbo

The engine is now clean enough to facilitate cooling and visual diagnosis of leaks. I'd leave it like it is.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.

You can always pop the valvecover off and give it a light hand polish job

Lye causes the protective oxidized layer of aluminum to break down and it looks pretty bad. You just need to polish it starting with 300 grit sandpaper and you're golden

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

WD-40 helps to clean it up from my own personal experience

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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

Thanks for all the replies! I don't have a camera with flash but I'm rectifying that ASAP. So I'll take a photo on my phone tomorrow morning and post it so you can see what I'm talking about. It's a chalky, cloudy bloom. I don't think the surface texture has changed but I want to make sure this isn't the start of some process leading to terror and gnashing of teeth.

Thanks again for the input so far! You're saving me from having horror-movie style nightmares where neither the co-ed or her car survive.

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1983 300TD 240k Thistle Green Auto (Euro) [sold]
1984 300D 240k Petrol Green Auto
覧覧覧覧覧覧覧覧覧
"You know, times are changing. Ladies can do stuff now and you're going to have to learn how to deal with it."
"What? Were you saying something? Look, I don't speak Spanish."

I'd call it oxidized.

Looks like it's Lye, my favorite chemical for cleaning Aluminum. Get the MSDS here: Products | SuperClean

I like oven cleaner better.

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Remember, Safety Third!
'99 E300 Turbodiesel, '82 300TD, 1996 12V Cummins Turbo, '94 Neoplan - Detroit 6V92TA

Maybe Superclean is what is needed for those nasty insides of the Intake Manifolds.
I read of more than one Member using Oven Cleaner.

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84 300D, 82 Volvo 244Gl Diesel

You can get NaOH from any soapmaking supply.
AAA CHEMICALS; LYE / SODIUM HYDROXIDE / LYE for SOAP MAKING, BIODIESEL, NAOH, FOOD LYE, RED DEVIL LYE SUBSTITUTE, LYE, LYE, LYE

I hear it works for clearing drains too.

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Remember, Safety Third!
'99 E300 Turbodiesel, '82 300TD, 1996 12V Cummins Turbo, '94 Neoplan - Detroit 6V92TA

Ok. Got a camera.

So some of it seems to be worse in a few areas. Is any of this stuff I really have to worry about? Any severe enough? I only realised after the fact that it shared the sodium hydroxide ingredient with oven cleaner which, you know, was thrilling.

I did put some metal protectant on it earlier at the front of the valve cover and it actually looks normal there now. Although maddeningly when I used a white rag to rub it in the rag came away dirty. Even after using some good ole lye on it. Still. Actually. Dirty.

Attached Thumbnails

     

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1983 300TD 240k Thistle Green Auto (Euro) [sold]
1984 300D 240k Petrol Green Auto
覧覧覧覧覧覧覧覧覧
"You know, times are changing. Ladies can do stuff now and you're going to have to learn how to deal with it."
"What? Were you saying something? Look, I don't speak Spanish."

If you want it to shine again, you'll have to take it off and polish it. Spray some WD, or some oil on it to stop the oxidation. There is going to by lye left over there, it will oxidize further on rainy or humid days, if you don't.

__________________
Remember, Safety Third!
'99 E300 Turbodiesel, '82 300TD, 1996 12V Cummins Turbo, '94 Neoplan - Detroit 6V92TA

Thanks! I will definitely use some WD40 on it tomorrow and some sandpaper if it's bad anywhere like you guys recommend. And I can finally see the leaks now which is weirdly comforting. Time to get cracking on all them then.

Thanks again for all the input, everyone!

__________________
1983 300TD 240k Thistle Green Auto (Euro) [sold]
1984 300D 240k Petrol Green Auto
覧覧覧覧覧覧覧覧覧
"You know, times are changing. Ladies can do stuff now and you're going to have to learn how to deal with it."
"What? Were you saying something? Look, I don't speak Spanish."

Steel wool works well too.

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Remember, Safety Third!
'99 E300 Turbodiesel, '82 300TD, 1996 12V Cummins Turbo, '94 Neoplan - Detroit 6V92TA

Steel wool and many types of sandpaper are bad news on aluminum. Small particles become embedded in the aluminum and cause corrosion at a later date. A 3M Scotchbrite pad (or similar) is a far better option.

I have cautioned against the use of surfactant-type cleaners many times, only to be told I didn't know what I was talking about. Well, this thread is precisely what I was talking about.

Interesting reading:

http://www.mechanicsupport.com/aircraft_cleaning.html