My engine bay cleaning technique.

T

The motor guy

Joined
Nov 29, 2009
Messages
10,258
Is this a good method? Just cover the air cleaner and distributor cap, then hose it down eith a garden hose sprayer attachment. Then after that take said machine out for a drive so dry off any water as I dont want any water sitting for any period of time. Then respray with anti corrosion spray. I like to use a marine grade spray that leaves a glossy waxy coating. The problem is the dust gets caked on and it needs to be washed off and re applied.
 
Distributor cap? Haven’t seen one of those in a few decades…

I use Simple Green for the spots where some gunk has built up. Gently rinse. No hard spray.

Wipe off the water. A bit of “Wipe new” plastic treatment on the plastic bits.

Good for a long time.
 
Astro14 said:
Distributor cap? Haven’t seen one of those in a few decades…

I use Simple Green for the spots where some gunk has built up. Gently rinse. No hard spray.

Wipe off the water. A bit of “Wipe new” plastic treatment on the plastic bits.

Good for a long time.
Click to expand...
My boat has one. Most boats still use a 350 sbc
 
I would cover the alternator too. I use regular car wash soap and a brush to agitate dirty / muddy areas then rinse. I like you idea of using anti corrosion spray. For dust, just wipe it w a wet rag
 
If you want a really clean engine bay, get out there with APC spray, and a bucket with a 1 to ten dilution of APC , warm water, brushes, and three times the number of microfiber towels you expect to need.

Or hit it quickly with a pressure washer every so often. There is no shortcut to a perfect engine bay.
 
blain450 said:
The distributor cap needs to be covered to make sure the points don't get wet.
Covering the generator is a good idea too.
Click to expand...
I know what a distributor cap is - and why it needs to be covered. I have a car with a distributor, dual point NorthEast, in fact, but my point was: most cars don’t have a distributor these days.

Most cars haven’t had a generator since about 1950.

However, I do cover the alternator where necessary.

The sealed, liquid cooled, alternators on the V-12s don’t need to be covered. The brushes are internal.

But I don’t wash those engines - 24 spark plug tubes that can collect water, causing shorts. A new coil retails for $1,450. Best to avoid getting water in the spark plug tubes and risking a short.
 
Donald said:
Your recommended product only shines & protects after cleaning.
Click to expand...
The OP said after he cleans the motor..."Then respray with anti corrosion spray. I like to use a marine grade spray that leaves a glossy waxy coating. The problem is the dust gets caked on and it needs to be washed off and re applied."

MotorPlast will not only make the motor look great, acts as a sealant to the plastics and rubber component, but it also has anti-static properties that will mean it will not attract future dust and dirt. MotorPast will also require no application other than simply spraying it on! I'm not aware of any other product that can match all of it's features and be easier to apply.

Ed
 
I used to wet the engine bay, spray it down with Simple Green, let it sit for 5-10 minutes, then hose off. I didn't cover anything.

Now I do the same except I use Dish soap in water rather than Simple Green, as Simple Green is corrosive.

My 2014 Town and Country with 135k miles has a gorgeous engine bay, though the engine now idles terribly...if only it ran as good as it looks.
 
svtrit said:
I used to wet the engine bay, spray it down with Simple Green, let it sit for 5-10 minutes, then hose off. I didn't cover anything.

Now I do the same except I use Dish soap in water rather than Simple Green, as Simple Green is corrosive.

My 2014 Town and Country with 135k miles has a gorgeous engine bay, though the engine now idles terribly...if only it ran as good as it looks.
Click to expand...
I dont know what simple green does. It does not clean much that I've found. I agree. Id think some dawn dish soap would work great, then reapply anti corrosion spray if necessary.
 
Because 409 cleaner had warnings about use on aluminum surfaces, I'm weary of non-automotive specific cleaner/degreasers. I do recall such a warning with Simple Green. Cleaner strength and dwell has a lot to do with it. FWIW - (from Grok):

Surfaces in Auto Engines to Avoid Cleaning with Simple Green​

Simple Green All-Purpose Cleaner is marketed as engine-safe for metals like chrome, stainless steel, and painted aluminum, but its alkaline pH (around 9-9.5) can accelerate corrosion, pitting, or residue buildup on certain unprotected or sensitive surfaces if not rinsed promptly (within 10 minutes max). User experiences and manufacturer guidelines highlight risks, especially on bare or coated aluminum, painted areas, and non-metal components. Based on automotive forums, detailing experts, and Simple Green's own FAQs, here are the key surfaces to avoid or handle with extreme caution:

Surface TypeWhy Avoid Simple GreenRecommendations
Unpainted/Bare Aluminum (e.g., intake manifolds, brackets, unpainted engine blocks)Alkalinity strips the protective oxide layer, leading to rapid corrosion, pitting, or weakening; banned in aerospace for this reason. Contact time >5-10 minutes worsens it.Use dedicated engine degreasers like Gunk or Detailer's Pro; pre-wet with water, dilute 1:10 if using SG, and apply protectant post-clean.
Painted Engine Bay Surfaces (e.g., valve covers, firewalls, fender liners)Can strip or etch paint/primer, especially full-strength; repeated use dries out clear coats by removing oils.Opt for automotive-specific APCs like Meguiar's D101 (diluted) or citrus-based degreasers; test in small areas.
Zinc-Plated or Galvanized Parts (e.g., bolts, fasteners, brackets)Attacks zinc coatings, causing white rust or seizing; submerging even briefly dissolves plating.Avoid entirely; use neutral cleaners like Dawn or WD-40 for light degreasing.
Rubber and Plastic Components (e.g., belts, hoses, air intake tubes, seals)Degrades or discolors over time, causing cracking or swelling; leaves residue that attracts dirt.Cover with plastic during cleaning; use silicone-safe protectants afterward if exposed.
Electrical Connectors and Sensors (e.g., wiring harnesses, alternator plugs, ECU)Water-based formula can cause shorts if not dried fully; residue promotes corrosion.Always cover with foil/plastic bags; use compressed air for drying, never submerge.

General Tips​

  • Dilution and Rinse: If using, dilute 1:1 for heavy grease, apply briefly, and rinse thoroughly with low-pressure water to prevent residue films that gum linkages or accelerate rust.
  • Alternatives: For safer engine cleaning, try Purple Power (diluted), Chemical Guys Orange Degreaser, or Engine Brite—formulated specifically for autos without the corrosion risks.
  • Testing: Always spot-test on inconspicuous areas, as alloy compositions vary by vehicle.
These insights come from real-world mechanic reports and Simple Green's guidelines, emphasizing caution over full-strength use.
 
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