Best way to clean the engine bay/underbody?

[Kruzen]

Lots of oil has been spilled all about inside of my engine, but i have no current leaks, (That i can find), so someone screwed something up before i owned the car, or accidently dumped a ton of oil everywhere.

in either case, i'm looking to clena up the engine bay alot, in general, would it be a bad idea to just cover up my alternator and distributor cap and what not w/ plastic bags and then spray the fucker down with a pressure washer?

[DanGillan]

pressure washing is good, yea cover the alternator, and the cap and rotor, and the air intake, and the fuse box, whatever exposed electircal connections you see, then hit it with the pressure washer (carfully) and some simple green, or diluted castrol super clean (purple bottle), or engine bright, that shit works good. then once your done, and it's dry. get a big bottle of armor all, douse the whole engnie bay.... EVERYTHING!!! and close the hood and let it sit overnight, its like bake off in an oven, the next morning, hose it off, dont do it too often though becuase "armoral makes rubber crack" supposedly, but once in a while wont hurt. a toothbrush helps a lot, and yea, just hit it with common sense...

[nando]

you'll also want to cover the fuse box and possibly airbox. remember, your car is not a submarine so treat it as such. if you want, spray the bad areas down with simple green or some other cleaner and let it soak before you wash it off.

I do it with the motor running, and just avoid spraying certain areas of the car, although last time I accidentally blew the cover off my fuse box

[KenC]

I wouldn't use a pressure washer in the engine bay... too much force.

Buy some 'Gunk' degreaser (Orange cap on can). It's nasty stuff, but it'll do the trick. And then you can get some Castrol Superclean (diluted to 8:1 - 10:1) and hit the spots that you missed. Then get some rubber protectant (ArmorAll or something like it), and spray down the entire engine bay with it (save for the belts) and let it sit for 10-20 minutes.

[e30Matt]

My friends and I always use spray-on foam tire dressing w/similar results.

[DanGillan]

thats the most hectic engine bay i've ever seen... but clean 8)

[e30Matt]

Were all the fans orange on M10 318s?

[Matto]

Were all the fans orange on M10 318s?

Looks sexy... :P

[EtaSport]

Whats been said is good. You dont really need to powerwash, but i have used one. If you have cosmoline get some rubbing compound or polishing compound and get what you can by hand. The engine brite foam will work well. My friend bought a can of engine detailer spray that is a very good investment. It is recommend to spray on rubber and metal. It will protect the rubber hoses and prevent any metal surfaces from rusting. Just look for some engine detailer at an auto parts store. Then use the steps the other guys mentioned. Last time i somehow got water into something and my car didnt run right for a while. All you can do is let it run so it can evaporate the water.

[hamann318is]

I used a wire brush on the exposed upper metal parts, came out awesome. Used to be green, but now a nice shiney sliver.

Castrol is what I used in the beginning, did it each morning for two days in a row and hosed off. Got some crud and cosmoline off, and I'm pretty happy with how it looks now.

[robert325is]

thats the most hectic engine bay i've ever seen... but clean 8)

[///M Powered]

Were all the fans orange on M10 318s?

no, at least not mine.

[grapedrink]

At work we degrease ALOT of cars. We use a presure washer with ZEP engine degreaser. Put the car up, spray some stuff on it and watch it come clean :) You don't need to put plastic bags etc over anything. Thats a bunch of crap. I have degreased more engines and underbodys than anyone here on this site. My work has been doing it for YEARS and nothing goes wrong. If your a dumbass and spray DIRECTLY at the electrical components for a LONG period of time then you deserve what will come to you. Use common sence to save you time. Your not going to have a problem.

[bimmerlover]

You make it sound so easy. I cleaned the engine bay of a 91 318 a while back, just before we put it out for sale. Dang it looked pretty.. BUT... it misfired and carried on for everyone who test drove it. I can't remember now exactly what was decided but I had definitely got water somewhere that I shouldn't have. Since then, I'm very cautious. I cover anything that even looks like it could be remotely electical -- with rags.

[Kruzen]

You make it sound so easy. I cleaned the engine bay of a 91 318 a while back, just before we put it out for sale. Dang it looked pretty.. BUT... it misfired and carried on for everyone who test drove it. I can't remember now exactly what was decided but I had definitely got water somewhere that I shouldn't have. Since then, I'm very cautious. I cover anything that even looks like it could be remotely electical -- with rags.

yeah, this happened for a week after i did it to my jetta back in teh day.