How do I go about cleaning all the old grease and dirt off the engine?

There are a bunch of engine-cleaning sprays & stuff at your standard McParts stores. Spray it on, let it soak, hose it off. Problem is that it makes a mess, and the "Gunk" type stuff ain't very good for the environment, nor is washing the oil/grease down the sewer. Many people use Simple Green or other similar household cleaners, which are pretty good and much better for the environment than the engine sprays.

Best way is to go to a local autowash that has "engine degreaser" as one of the sprays. Let the engine cool down, spray that stuff all over, let it soak, then do a standard soap and rinse spray. You have to make sure the engine is cool--you could muck things up spraying cold water on a hot engine. If you use the long "wand" type sprayer, it's a lot easier to get to the underside of the engine and trans which are often the most gunked up. You also don't want to get the degreaser on your paint--at the minimum it'll remove all the wax.

For a diesel, the only thing you need to be careful about is the alternator--don't do a direct hit on that with a high-pressure spray. Nothing else on the engine will be hurt by the degreaser. Also be careful about the battery and the fuse box on the fire-wall--a little overspray won't hurt them, but you don't want to blast them with water.

The car wash should have a re-cycler and will filter out all the bad stuff and the grease & oil.

Good luck.

I clean my engine regularly with gunk engine degreaser. I wash the benz at the do-it-yourself carwash (in this time the engine cools down), I spray the entire can all over, and liberally spray everything. Never had any problems, and it makes the car nicer to work on.

I have used Simple Green with a garden sprayer. Easy to do, just pour some in straight our of the bottle and soak the old oily stuff down. It works even with engine cold. Come back a half hour later and hose it all down with a garden hose. You can avoid getting car wash spray on a hot engine this way. I have read here warnings about getting any cold water on the IP, it is a very precision part that does not like to get a cold shock.
Cost of a gallon of Simple Green, or better yet the orange degreaser, sold is about the same as a car wash spray or two anyway and a gallon will go for a long time. Get one of those one gallon sprayers and you will be set for life.

Shock cooling a motor can be bad, but unlikely in my opinion by washing it at the local pressure washer. We all drive during rain storms and over puddles and water splashes up in the engine compartment, also, I have been washing my motors for years with good results and no problems by first misting the motor from far away, then getting closer with the pressure. I find that with the pressure washer, I don't need to use any degreaser - try it both ways and you'll see what I mean. Avoid electrical connections like the other gents said as well. good luck!

I second that. I just cleaned my engine, which had more than a few years worth of grime (hanging my head in shame), with Simple Green. Car was cold (I was attempting to replace the water pump at the same time), I sprayed a little water from the hose, spritzed some Simple Green on. I waited a few minutes and scrubbed some of the thick spots with a toothbrush. Rinsed off and it was clean as a whistle. And Simple Green isn't bad for the environment.

__________________
1984 300TD Turbo 156Kmi
"He who seeks knowledge begins with humbleness" - Buju Banton

To All,

Not trying to sound too much like a tree hugger here, but depending on where you live, caution is in order.

Some municipalities forbid using the self-serve car washes for cleaning engines. They often recycle the water and the extra crud that comes off the engines doubtless causes problems--

And though Simple Green works great, the oil and grime it removes just doesn't go away. Some counties, such as the one I live in, are set up so storm drains go the ocean, and it is considered an equivalent to dumping oil if you are caught washing pollutants into the gutter.

I like a clean engine just as much as you do, but I don't want anyone to get into trouble!

Regards,

__________________
Nate Stanley
(Currently Benzless)
1985 F-250 6.9l 170K
2009 SCION XB 36.5K
2003 LS430 78K
2012 Kubota B 2320

Well said Nate!!

Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.

Sometimes it can be counter productive to clean all that gunk off the engine. That gunk is probably stopping or slowing down an oil leak. Unclot that and there she flows.

__________________
1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

Well, I bought a bottle of Simple Green today. I parked the car in the back yard, covered the battery with plastic bags and sprayed the engine with a water hose. I then sprayed Simple Green over the entire engine, scrubbed the areas I could reach and let it sit for awhile. After I hosed down the engine again I could really see a difference, a clean difference. Although I couldn't get all the grime off the first try, I'm sure I'll get it cleaner the next go around.