Is it really safe to clean the engine bay using a hose and water?

I'm tempted to clean it because it's disgusting in there. But I was told to watch out for certain components such as the air filter and distributor. But I'm not sure how I would go about "protecting" these. Put a bag over them? The Air Filter is already in a plastic housing isn't it?

What about the intake? I know it's bad to drive through water because water will get sucked into the intake and destroy the engine so how do I prevent that from happening by spraying water on the engine?

What about the wires like the spark plug wires and the various connectors scattered about? What happens if water gets on them and gets inside inbetween where contact occurs?

I'm thinking of using Simple Green, scrubbing off the grease and hosing it down. The engine especially has some nasty looking oil leaking from the gap between the valve cover and the engine body which I assume is due to a worn valve cover gasket and possibly the spark plug seals are worn as well but I did not have time to check those yet. The other day I couldn't start the car, it would crank but not start for a couple of attempts. I'm thinking the tips are oil fouled.

So is there anything I need to watch out for? This is on a 1993 Honda Accord LX (4-cyl 2.2L).

 

I washed my engine before, right after i put the new engine in. I used some engine degreaser, spray on and let it sit for a few minutes and just hose it off, i did that with the engine running, just don't get crazy with like alternator, exhaust manifold/header belts, might get squealing afterward. I used air to blow dry it, under the hood now is way cleaner than before.

 

Avoid getting water on the alternator and the distributor.

Put a plastic bag over these items to prevent getting water on them. You may have to take off the alternator belt to get a bag over the alternator.

 

Alright, thanks guys. To put the bag over the distributor should I take the spark plug wires off at the boots where it meets the distributor?

Also do I have to worry about rust if I let it dry? There's already a small bit of rusting going on under the hood (particularly on the plate that says HOT with the hand on it that's on the engine.

Mostly salt or some kind of mineral deposits though.

 

It's just the heat shield for the exhaust manifold, no big deal, just don't spray too much water where the electronic components are, a little wet will dry out from engine heat.

 

I have been spraying my Accord (92 & 03) engine bays off with the high pressure car wash. Never had a problem. I will let the engine cool off while I wash the outside, then open the hood and go to town. I don't cover anything. The wire connections on these cars are sealed very well, and packed with dielectric grease, so there's not much chance water can get in. I would not try it with my Chevy truck, because the wires and connectors don't look like they are sealed half as well.

 

I don't see any grease on the plugs where they meet the sockets.

Should I start now? Apply the dielectric grease all over the sockets/plugs and then hose the engine bay down so the water doesn't get in?

 

i sprayed my engine when i had a geo metro and fried my ecm.

ive been scared to clean my engines ever since...

 

I would not clean it if you know the valve cover gasket is leaking. If oil is getting out then water can get in. And while water on the outside is fine, water on the inside can cause some trouble.

 

Other than Rice's concern about water getting inside, Simple Green is OK for most stuff under the hood. Just don't go wild with spraying water everywhere.

Cover up the brake fluid reservoir too. There's a tiny little air vent in the cap.