bad to pressure spray engine with degreaser?

[ez at nova]

In an attempt to somewhat improve the filth of everything under the hood, I was thinking of getting some Simple Green and spraying that on the engine all over, then diluting some in a bucket of water and using this attachment that says it's for engine cleaning, for my air compressor that draws the liquid up and makes it a sort of pressure washer.
1. Should I NOT be jsut hosing everything down with the simple green?
2. Should I NOT be spraying everything down with the presurized water?
The last thing I want to do is marginally improve the underhood appearance and be left with a broken car.

 

[tom h]

In the past I've had some bad experiences using high pressure water. It's far too easy for water to get inside electrical components, accidentally knock off small vacuum lines you don't notice, etc.

I prefer to use full strength, detergent based degreasers (no solvent-based, which can damage hoses and wires), a variety of brushes and rags, and then gentle water spray to rinse it all off. Follow with a leaf blower for the big water puddles, and then drive until the engine is at full temperature for a while.

Even then, I'd be reluctant to pour rinse water directly onto certain electrical components, like the ignition module.

Rubbing or brushing will always get surfaces cleaner than just spraying water, anyway, unless the spray is of such high pressure the paint gets blasted off!

 

[SFITurbo]

Greased Lightning and a little scrubbing on the heavy stuff, then rinse with a hose. Stay away from the alternator and DON'T get it on the body. Top off with some WD40 all over for some dressing.

 

[Skylark-69]

I've seen some guys put plastic bags with a rubber band around potentially sensitive electrical components before applying water.

 

[Gary Wells]

FWIW & IMHO:
I use a high pressure hose as in the car wash kind, I do not mask or plastic bag anything, and spray away. I have done this on virtually every car and motorcycle that I have ever owned. At least for the 25 years or so. I have never had a problem of any type. BTW: '86 or so corvettes are sort of sensitive on the tps.
But I have never had a proble on any of the 5 turbo regals that i have owned. Even though it is the same tps. Go freaking figure.
HTH

 

[MistaScott]

My opinion: Do it by hand.

There are too many solenoids, sensors, ignition components etc. to have to worry about covering in order to spray all over. Elbow grease and TLC will work wonders.

 

[ez at nova]

results

Well, in case it helps anyone else in the future:
This was the first itme I've used the apparatus that hooks to the air compressor and has alittle hose that goes to a bucket of water to function as a siphoning pressure washer thing. Upon hooking it up, it inspired confidence in me to use it because it really looksed pretty harmeless. This is a FAR cry from my dad's pressure washer I've used. Where I could see that thing doing some damage, this thing was functioning 90% like an air hose sprayer attachment, and 10% like a pressure washer. It was almost like 90psi of air coming out with a mist of the liquid. I forgot to stop and get simple green, so I figured I'd just use dish detergent since that should cut grease. I wend over the whole engine and it did a fair job. Not stellar, but the point is,my engine compartment looks cruddy not due to dirt and grease, but due to 15 year old parts that look work, yellowed, rust coated, pitted, etc. So, I was expecting too much. Everything is clean now...it's just old looking! I'm at the point now where I have to start taking parts off like the valve covers, headers, etc, to have them blasted and recoated I suppose. Anyway, I went back over the engine with jsut a garden hose to rinse the soap, then dried it with a pure air attachment to the air hose to get the moisture out of the electric areas. It ran fine last night so I guess it's fine.

Thanks