Engine Bay and Undercarriage wash?

SLOWBRA

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Oct 30, 2001
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I'm gearing up for a in-depth degrease and wash for the engine bay (and undercarriage) on my 93. What is the best technique for using cleaners and washing given the paint in the engine bay isn't clear coated? I'd like to know the approach, what brushes, degreasers (dilutions), etc. you use.

The top end is off along with most of the hoses so I have a lot of access. Alternator is covered, intake holes taped up, and the connectors are all taped up. I'll be doing this on my lift so that I can be as thorough as possible.
 
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RekeHavoc

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Dec 5, 2019
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I can tell you what NOT to do. Whatever you do, don't use Super Clean full strength. I used the foaming aerosol and it removed the paint in a few small spots on 2 of my cars. It might be ok diluted, but I would probably avoid it completely just to be safe.
 
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7991LXnSHO

Now I want a 10 year badge
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LA Awesome is a shockingly good degreaser, and it’s at the Dollar Stores. There is enough ammonia in it to choke you bad in enclosed spaces. But it kicks Simple Green’s container.
 
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Essn95

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Jun 21, 2017
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I used simple green with good results. Heard of success with purple power but I didn't want to ruin the finish on my CAI
 
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90sickfox

Wasn't a pretty sight...and I've got big hands
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Purple power will corrode aluminum.
Always vacuum or blow as much loose crap out as possible.

I have very good results with a cheap fluid sprayer from Harbor Freight that hooks to an air line. There's a clear tube that goes in whatever cleaner you use. I like regular old Dawn dish detergent. It's safe enough to wash oil off ducks so it won't damage anything under the hood. For scrubbing you want a few different brushes. A paint brush with the bristles cut down to about an inch helps get caked up stuff off.

White Diamonds is the best metal polish I've ever used. Will polish regular steel to a chrome like finish. It polishes headlights after a wet sand with 2500 grit and works on weathered car paint. ( I've been very successful but due to it not saying so on the bottle test a small unseen area first.

Back to Black is my choice for hoses and black plastic. It's non greasy and won't attract dust. Makes the plastic and rubber look new.

A steam cleaner would be the best way but I haven't sprang for one of those yet. A detail shop I used to hang at used one all the time for detailing all types of stuff inside the car and under the hood.

This thing is cheap but works.

Screenshot_20210407-003112_Chrome.jpg


People use simple green for cleaning under the hood, but I haven't. I have used purple power in the past but you have to make sure you get old of it rinsed off any aluminum or it'll get ashy.
 

Specracer

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Nov 24, 2020
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Very greasy ive had good luck with Engine Brite, mixed with elbow grease. When in winter, and not able to use a hose, I used a pan with Zep parts washer solution out of our parts washer, and a host of different brushes. After that I use a diluted (50 50) orange citrus degreaser. In the Zep family the purple is too strong. Then rinsed with water.
 
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SLOWBRA

Founding Member
Oct 30, 2001
287
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NC
Purple power will corrode aluminum.
Always vacuum or blow as much loose crap out as possible.

I have very good results with a cheap fluid sprayer from Harbor Freight that hooks to an air line. There's a clear tube that goes in whatever cleaner you use. I like regular old Dawn dish detergent. It's safe enough to wash oil off ducks so it won't damage anything under the hood. For scrubbing you want a few different brushes. A paint brush with the bristles cut down to about an inch helps get caked up stuff off.

White Diamonds is the best metal polish I've ever used. Will polish regular steel to a chrome like finish. It polishes headlights after a wet sand with 2500 grit and works on weathered car paint. ( I've been very successful but due to it not saying so on the bottle test a small unseen area first.

Back to Black is my choice for hoses and black plastic. It's non greasy and won't attract dust. Makes the plastic and rubber look new.

A steam cleaner would be the best way but I haven't sprang for one of those yet. A detail shop I used to hang at used one all the time for detailing all types of stuff inside the car and under the hood.

This thing is cheap but works.

Screenshot_20210407-003112_Chrome.jpg


People use simple green for cleaning under the hood, but I haven't. I have used purple power in the past but you have to make sure you get old of it rinsed off any aluminum or it'll get ashy.

Thanks to you and others for the feedback. The ideas with the paint brushes make sense. Another member suggested getting paint stirring sticks and wrap them with throw-away towels/microfibers for tight spaces. The one thing that I hadn't seen before is the engine cleaning gun.

The engine appears to have a fine mist of oil/grime everywhere under the hood. I can also see where the oil fitting/sensor created a nice mess. My goal is to get it back to what it should be for a low mileage car. I love the idea of Dawn, but wasn't sure how quickly it would clean. Perhaps I'll use Dawn with hot water anywhere near paint and use my chemical guys Orange cleaner on the engine it self.

I have a steamer that can be used. Haven't used it for anything other than removing stickers to date, but it cranks out some steam!
 
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90sickfox

Wasn't a pretty sight...and I've got big hands
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With a steamer the gunk just melts away. Fawn is a really good degreaser. It's made to cut grease and to not leave a film or residue on glasses. Steam is still the best I've seen in person but that type of steamer is still expensive and I'm not a detailer. Lol

That nozzle thing is like a little light pressure washer. It'll get stuff out of the crevices and won't harm paint. It will knock off chips of paint on badly spray painted stuff that's already lifting.
 
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91AOD5.0LX

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Feb 20, 2021
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I use cycle care formula M to bring pitted chrome and aluminum back to a shine as well as it can for 30 years old.
Before and after pics and not even going “all-out”
 

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91AOD5.0LX

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My engine bay cleaning kit consists of spray wax, spray bottle for Dawn solution, color paint pens for detailing, ultimate black rubber hose restorer, micro fiber rags, mr clean pads (awesome), simple green towels, paint brushes of different sizes including artist brushes, pipe cleaners of different sizes with micro fiber on the tips and straight up wire ones, and wire hand scrubbers. Engine paint and others for the wire looms, etc. lots of time and elbow grease but eventually everything comes looking 90% new.
 

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All Stock93

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I have had great results mixing Dawn dish soap ( the original blue stuff) with vinegar in a spray bottle then wiping with a microfiber cloth.
This mix is what I used to clean the engine bay and undercarriage of my car before the MCA Grand National show a couple of years ago. It's not as strong as some solvent cleaners but it does work well.
You can see the underside of my car after cleaning with Dawn and vinegar in my album:
 

7991LXnSHO

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So what model and make of steamer do the OCD and detailers use?
mare they run by a gas engine (like a power washer) or 110v powered?

On a tangent, besides wanting to clean cars, I have long wanted a boiler/steamer to spot kill weeds. A tea pot of boiling water kills off plants quickly, even those that are roundup resistant. It does not upset the neighbors like a flame thrower killing weeds in the drive and sidewalk cracks, but trips back to the stove make for slow work
 

SLOWBRA

Founding Member
Oct 30, 2001
287
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18
NC
I have had great results mixing Dawn dish soap ( the original blue stuff) with vinegar in a spray bottle then wiping with a microfiber cloth.
This mix is what I used to clean the engine bay and undercarriage of my car before the MCA Grand National show a couple of years ago. It's not as strong as some solvent cleaners but it does work well.
You can see the underside of my car after cleaning with Dawn and vinegar in my album:
Incredible pictures. Great job. I definitely don't want my 93 that nice.. lol. I've got three other garage queens that only see fair weather and are that clean. The 93 needs to be close, but not so good that I won't drive it in the rain :)
 
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MustangIIMatt

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When done cleaning the undercarriage, don't forget to rust-proof:

 

SLOWBRA

Founding Member
Oct 30, 2001
287
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NC
When done cleaning the undercarriage, don't forget to rust-proof:

It's funny that you mentioned that. Mine certainly has a thin layer of oil/grime from never being cleaned in 30yrs. However, it is rust free and I'm confident it will look nearly new when done. I will want to keep it that way for another 30+yrs.
 

Zero_chance

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Plus one for the steamer. Got a relatively inexpensive one from Amazon after stressing over spraying water, not to mention the fact that we have high calcium hard water out here so it would’ve required a post cleaning cleaning. Couldn’t be happier.
 
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HemiRick

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Jun 28, 2020
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Wow can't believe no one has mentioned a pressure washer....Great for cleaning damn near anything IMHO I've used them on engines and bays, seats, carpets, etc.