Several people have asked for this particular write-up...and since we aim to please I'm going to go ahead and post it, even though I find the water/gas carrier discussion MUCH more interesting.
Washdown: Easier Than Expected
Okay, Darlings, make sure you're sitting down and resting comfortably: this next little bit of information is almost sure to fuse your cerebral lobes together should you not take all due precautions...
Your engine is not allergic to water.
...
...
...!
Yeah,
that was the big news flash. Those of you that still have higher brain function can continue relaxing and paying attention...and the slower members of the class can go have their cookies and juice boxes, now.
Pictured: I miss recess, too.
The rest of us can have cookies when we're done washing our engines. Before we learn how to do that, though, I want to address a concern that several people have mentioned and that essentially eludes my understanding: hydrolocking an engine by washing it.
Now, I understand the nature of a hydrostatic lock, and I know what it does to an internal combustion engine: it bends connecting rods and sometimes sends pieces of them - and other things - through the cylinder walls. Hydrostatic locks occur when some manner of liquid - it doesn't have to be water, mind you - enters the cylinder in an amount greater than the compressed volume of the cylinder itself. Water can cause it, of course, but so can coolant, oil or any other liquid that you can imagine...you could probably do it with cake batter if you tried hard enough. What I just don't comprehend is how people expect to accomplish it through a simple wash-down.
Consider the following picture of an engine that's badly in need of cleaning and tell me exactly how many ways there are to easily get water into a cylinder. Actually, don't answer that...I'll answer it for you: none.
Pictured: A lack of funnels that lead directly to combustion chambers.
Unless you direct the hose into the intake horn in the lower left corner of the photo you're very, very,
very unlikely to get any significant amount of moisture inside your engine's combustion chambers. If you plan on doing something of that nature then just go ahead and drown yourself now and save us all the trouble of another "OMG how did i break my Jeep plz help!!!" thread on the Tech Forum.
Those of you that are A) still reading and B) not total f***tards may remember the part above where I stated that your engine isn't allergic to water. Well, that's the literal truth...water exists in your engine
all the time, and not just in the cooling journals in the block. Water is present in the air that the engine mixes with fuel - it's called "humidity" for those of you in Phoenix - and as such, your engine breathes it and processes it with every rotation. As far as the intake of water is concerned, washing your engine is fundamentally no different - nor any more dangerous - than driving in a rainstorm. Deeper inside, in the cylinders, water vapor is even less of a concern. If we consider a simple formula for combustion, such as...
2 H2 + O2 → 2 H2O(g) + heat
...we find that
water is a byproduct of combustion reactions. For those of you that don't have a degree in either chemistry or orbital mechanics: the formula basically explains that a fuel and an oxidizer produce water and heat energy when they are combined. It also explains the mechanism that a Saturn V uses when it tells gravity to go f*** itself.
The point that I'm making, here, is that getting water into the engine while washing it isn't really a concern. If you
really want to worry about a hydrolock, go do a water crossing: you'll quickly find that your axles and differentials and transmission are in
far more danger than your engine, providing that you don't submerge the intake. In fact, the only portions of your engine that are usually in any sort of severe jeopardy are the electrical sensors...and as luck would have it, we are already in possession of a way to prevent damage to these areas as well.
Pictured: You knew this was coming.
That's right, you guys -
and girls - get to play with the f****** dielectric grease. Electrical connections need neither air nor water to function properly, but often suffer from the interference of both at once...thus, we need to eliminate them and this otherwise-offensive tube is the way to go. Before you start washing ANYTHING you want this stuff in any connection that might possibly appreciate a lack of water, oxidation or corrosion...because those three things are the biggest sensor-killers in the Wasteland. Remember my episode with the TPS and IAC? Water got them: the engine kept running, but the electrical dysfunction suffered by those two sensors would have been completely preventable had I been a touch more judicious in my preparations.
Valuable Information: Anytime you have an electrical connection apart and think that it could stand some water-proofing, apply some f****** dielectric grease.
So, assuming that you've done the preliminary work of waterproofing your sensors and you're not stupid enough to shove a hose end inside your throttle body, you're ready to start washing, right? Wrong, Sucko! We're going to rinse out the frame, first.
Pictured: And here's why.
Yeah, you guys -
and girls - know how militant I am about keeping Greta clean...and this kind of stuff
still winds up sloshing around inside her frame rails. Fortunately, getting it out is easy.
Step 1: Direct water through this hole in the frame rail, just in front of the rear tire.
Step 2: Watch in delight as the horror runs out the drain holes towards the front.
You will notice that there are several holes here and there in your frame...I'd suggest using as many of them as you can reach in order to get out as much grime and dirt as is possible. When the water runs clean, you're done, and you can move on to the engine.
Valuable Information: You could always do this step after you clean the engine, but one of the main points of engine cleaning is this: DON'T WASH A HOT ENGINE IF POSSIBLE. Warm is fine but hot is not, because Cold Water + Hot Metal = Steam. You're likely not going to hurt the metal or the paint or anything else under the hood - and the steam may actually loosen some grime, here and there - but working around hot steam isn't very safe. When you go through a car wash with a hot engine you have a layer of sheet metal or glass between you and any generated steam; this is not the case when you're standing over your hood with a hose. I park and wash anything I can think of before I get to the engine, and that gives it plenty of time to cool down to non-steam-inducing temperatures.
Since Greta doesn't see a lot of mud, I usually don't have to do much work on her lower sections. Thus, I start with the top, and I give the engine bay a thorough washing-out to get rid of any non-adhered filth. After that, I soak everything I can reach with Simple Green...and I seriously will use half a spray bottle of it. It's paint-safe, biodegradable, and a pretty good degreaser.
Pictured: However, it almost makes for the worst FPS of all time.
Here's a better shot, showing the relatively large amounts used. I wasn't kidding when I said I soaked everything.
Pictured: Seriously, get it everywhere.
If you haven't done much cleaning of the engine bay before, your first attempts will likely require some brushing in order to loosen the caked-on stuff...and that's another reason to do the cleaning when the engine is COLD. Whatever technique you want to use is fine, as long as you don't let the degreaser dry on the surface. After this initial cleaning, you can basically let the Simple Green sit on the surfaces for a few minutes and then spray it off.
Not Pictured: That white T-shirt from the last update. 
Those of you that go through mud will want to also do this step on the undercarriage; Greta doesn't see much mud, so I just let the draining water wash off what little road grime she collects. If you wash the engine bay often, you'll find that there's simply not much time for anything to get severely dirty. Once everything has been rinsed, leave the hood open and let the engine dry COMPLETELY and then apply the Official Muppet Labs Uber-Top Secret Engine Detailing Forumla.
Pictured: Available...pretty much anywhere.
Yep, that's the trick: tire wet...the odd substance that mall-crawlers actually use on
tires. Spray it pretty much wherever you want...it's hard to get too much on anything, and it really doesn't matter if you do so. All we want is a layer of protection/niceness on the visible surfaces.
Pictured: Second-worst FPS of all time.
You don't need to use half a bottle - leave that to the mall-crawlers and their never-off-the-pavement TSL's - but you DO need to be somewhat even in your coverage or you'll get bleached-looking spots. Since it's safe for rubber you don't even need to avoid the belt or hoses; in fact, I make
sure I hit these areas. If you get overspray on anything outside of the engine bay, it'll get washed off in short order. Once it dries it loses the wet look - perhaps due to the heat in the engine bay - and you're in good shape.
Pictured: Sexy.
Anyway, that's pretty much it. You can start the Jeep and note that you haven't hydrolocked anything and that none of the warning lights are going off...and now you have an engine that's MUCH more fun to work on because you're not getting grease all over yourself or your lovely assistant.
But in case you do get grease all over her you'll want to make sure you have a fully-stocked Girly Things Kit on-board. That's coming up soon...so stay tuned.
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The Wasteland Survival Guide: Engineering Greta
