best way to clean a dirty engine?

[Sam Humans]

My engine is DIRTY. Oil+Atf+sand=layers and layers of grime. What's the best way to clean this beast? Given the nature and position of the engine, given the location of some of the perhaps fragile wiring harnesses etc, how have some of you gotten your engines sparkling clean?
thanks!
-S

[djshimon]

I use the pressure washers at those u-wash-its. hasn't seemed to hurt anything yet... just squeeky belts after for a few minutes.

[timsrv]

Yeah, the pressure washer at the car wash is good, just don't get the nozzle too close to the harness or insulation as it will tear this stuff up a bit. Then of course there's the splattering of greasy gunk on your interior, so protect against that as necessary. Before I use the pressure washer, I soften up the junk with mineral spirits paint thinner. I have a sprayer I apply it with, then let it sit for at least a half hr before hitting it with water. There are other products out there like engine degreaser in a can, but some of these products may damage the painted surfaces (sorry, I don't know which ones are safe).

Mineral spirits won't damage anything. It will however make the distributor cap dust seal (rubber gasket between the cap and body) soft and cause it to expand, but it will shrink back up again after it has a chance to sit. I usually have a couple of those laying around and will usually pull the cap to blow this area dry anyhow. Before putting it back on I swap the seal and put the old one in a safe place to "dry"............it then becomes my spare for the next time. Tim

[Dogfish]

Mineral spirits works great but is expensive if you need tons of it. The engine cleaner in spray cans work ok and the spray is a plus for hard to reach areas. They smell like they are a relative of kerosene/diesel though a lot more expensive. I just use diesel.

I pick up 5 gallons of diesel or kerosene, which ever is cheapest/closest at the time. I used to get a gallon for about the price of a pint of mineral spirits... don't know if that is still true. I put it in a squirt/spray bottle and spray areas of accumulated dirt as I work on the engine. Makes a good parts cleaning bath, too. It still cleans well after it turns black and doesn't evaporate too rapidly. Let it soak, apply more to flush the grime, scrub with a brush if necessary and if you want it really clean follow up with mineral spirits. Flush with water and detergent if necessary.

If you use kerosene, diesel or any flammable solvent to clean your engine remember to flush with water to remove any remaining cleaner... it will smoke for quite some time when the engine gets hot (been there).

The usual cautions about testing on all surfaces other than metal apply... probably not good for hoses and wiring.

-Jim

[timsrv]

Safety and flammability is a good point. I've used "solvent" before and couldn't tell the difference between it and mineral spirits (even smells the same). The only difference I know of is price and flammability (it won't burn). If you use it in a parts washer, and don't change it regularly, it will become flammable though (as it mixes with oil and grease from the parts you're cleaning). Napa sells gallon jugs of solvent. It's usually over by the paint supplies and comes in a white plastic 1 gal container (like a bleach bottle) with black print on it.

If I remember right, mineral spirits costs about $7 per gal and solvent costs about $12. On average I use about 1/2 gallon to thoroughly clean an engine. Of course I'm mainly using it to soften the grime. The real cleaning comes when I hit it with the pressure washer :yes:. Tim

[ARP]

I assume y'all bag the alternator - any other areas need special protection with these methods (solvent first then pressure washer)?

[timsrv]

I may clean my engine about once every 5 years, so I never really worried about protecting anything. I just spray it down, then dry the distributor area. Then I usually run it hard for about 10 minutes to dry off the rest of the engine bay.

Of course I typically only wash mine just before maintenance and/or other engine work, so the fluids and filters get changed immediately afterwards. Tim

PS: I always figured that solvent and water can't be as bad for the alternator as power steering fluid, so never worried about it. Tim