Has anybody ever washed the engine on a [DSM]?
How do you wash the engine on a [DSM]?
What parts do I need to cover when washing the engine bay?
I washed the engine on my [DSM], and now it won't run! What's wrong? Is there a fix?
My [DSM] won't run! I washed the engine, and it started fine then! What's wrong? Is there a fix?

Brian Hood washes his engine all the time. See his description of how to do it here.

Aside from the cam/crankshaft angle sensor problem (described below), the process is simple: Spray everything with a cleaner, scrub as desired, and wash off. (Foaming cleaners might stick to parts and odd-to-reach places better.) Some people dry with compressed air or towels. For rubber and plastic parts, Armor All and similar products can be applied; for metal, Nevr-Dull or Mothers Metal Polish; and so forth. Tools like scrub brushes, Scotch pads, and the like can all be used.

With one exception, electrical components under the hood can be washed. Note that there are one or two that might suffer if blasted hard with a high-pressure stream of water. For this reason, most people recommend a simple garden hose, although a pressure washer can certainly be used if a little care is taken.

There is one important caveat to the advice above. Every year a few owners have problems immediately or shortly after washing their engine. All have damaged the camshaft angle sensor on the car. Without this sensor, the ECU cannot tell what position the crankshaft is in, and the engine cannot run. Some years have a crankshaft angle sensor instead; the effect is the same.

This makes the cam/crankshaft angle sensor the only real "must cover" part on the engine. A medium Ziploc bag or Saran Wrap is fine as long as the main body of the sensor stays dry.

The sensor in question is located next to the throttle body on top of the engine. It is round, about four inches in diameter, an inch thick, and grey in color. On turbo models, it is located immediately to the left of the words "16 Valve" on the top of the engine (see this picture for location).

If the sensor is covered the engine will probably start up fine right after washing. However, driving the car with a wet engine will create steam, which will get inside the crankshaft angle sensor housing. Once the car is shut off, the steam condenses into water, which will still wreck the sensor - even if it was covered prior to washing. Thus, some unlucky owners will find the car starts fine after cleaning, only to be "dead" the next morning.

So, to prevent crank angle sensor damage, therefore, there are TWO steps:

* cover the crankshaft sensor

and:

* wait until the engine is mostly dry before driving, or
* drive it for a while and then raise the hood to allow the steam to escape, or
* drive it long enough to get the engine completely dry.

Some owners are able to 'revive' their sensors, as Brian Powell was able to do here, but most are dead. Some Digesters have investigated if they can be repaired, but so far nobody has been able to do so. So don't get into a situation where you need to replace it.