What You'll Learn
Aussie Conditions
Look, I get it. The engine bay is the 'scary' part of the car for most folks because of all the wires and electronics. But honestly, if you're living in Oz, you've got salt air, red dust, and oily gunk baked on by the 40-degree heat, and that stuff eventually eats your hoses and plastics. This guide is for anyone who wants to do it properly at home using the right gear. I've cleaned thousands of bays from muddy Hiluxes to fragile Ferraris, and the method is pretty much the same.
Why Bother Cleaning Under the Bonnet?
The Gear You'll Need
What You'll Need
While you're here...
Preparation is Everything
Cool it down
Never, ever spray cold water on a hot engine. I made this mistake on a black Commodore once, the steam was insane and I'm lucky I didn't crack the manifold. It should be warm to the touch, but not hot.
De-leaf the bay
Pick out all those dead leaves, twigs, and gum nuts caught near the firewall and the base of the windscreen. A vacuum or leaf blower is your friend here.
Cover the 'No-Go' zones
Chuck some foil or plastic over the alternator, any exposed air filters (pod filters especially), and the fuse box if it looks a bit loose. You don't need to be airtight, just stop a direct blast of water from getting in.
Disconnect the battery (Optional)
If you're nervous or working on an older car with dodgy wiring, just pop the negative terminal off. No dramas, better safe than sorry.
The Step-by-Step Clean
Initial Rinse
Give the whole bay a light misting with water. We just want to loosen the top layer of dust. Don't hover the pressure washer over electrical connectors.
Apply Degreaser
Starting from the bottom and working up, spray your degreaser everywhere. Be generous on the greasy parts of the block and the lower subframe. Avoid getting it on the paintwork of the guards if you can.
Agitate with Brushes
This is where the magic happens. Use your brushes to scrub the plastic covers, the battery tie-downs, and the strut towers. If you've got red dust caked in the corners, use a small brush to wiggle it out.
Clean the Underside of the Bonnet
Don't forget the 'ceiling' of the engine bay. If you've got a fabric liner, be gentle. If it's bare metal, hit it with the APC and a brush.
The Final Rinse
Rinse everything off using a gentle flow. Start from the back (firewall) and work your way forward. Keep the nozzle moving, never stay in one spot for more than a second.
Inspect and Repeat
Most of the time, you'll miss a spot on the first pass (we all do). If there's still gunk, hit it again while it's wet.
The Blow Dry
This is the most important step. Use your leaf blower or air compressor to blast water out of every nook and cranny. Pay special attention to spark plug holes, electrical plugs, and the alternator. You want it as dry as possible.
Remove Covers
Take off your foil and plastic wrap. Wipe down those areas by hand with a damp microfibre.
Start the Engine
Fire it up and let it idle for 5-10 minutes. The heat from the engine will evaporate any remaining moisture you couldn't reach.
Apply Protection
Once the engine is dry and warm, spray your plastic dressing over the hoses and plastic covers. I don't bother wiping it in yet, I just let it sit for a bit.
The Final Buff
Take a clean microfibre and wipe off the excess dressing. This leaves a nice factory matte finish rather than that greasy 'used car dealer' look which just attracts more dust.
Don't Waste Money on Engine Shine Sprays
Watch Out
Keeping it Clean
Common Questions I Get Asked
Will I hydrolock my engine?
What if my car won't start afterwards?
Can I use dish soap?
How often should I do this?
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