Pressure washing your engine bay, i've read mixed opinions.
 

Obviously if your going to even consider pressure washing your engine bay you want to cover things like your alternator, fuse box and any other key electrical things. I want to detail my engine bay soon, most of the engine degreaser type products require you to spray on the product, leave it for around 10 mins, possibly agitate it with a brush and then pressure washer it off.

What's your take on pressure washing the engine bay as i've read mixed reviews online.

One thing to watch is the crinkle paint on the manifold if you have it.

I've previously used a hose in the engine bay with a sprinkler attachment (after applying degreaser on it and agitating with a paintbrush) but I wouldn't be comfortable to pressure wash it.
As you say, make sure you cover any electrical connections (MAF, sensors, alternator etc.) with foil.
I've also covered the oil cap, oil dip stick and expansion tank caps with foil for peace of mind more than anything else.

If I was doing it I'd disconnect the battery before starting and not reconnect it for a few days to let things dry out just in case water did find its way inside a connector. And use as little pressure as possible.

Polished Bliss's engine bay washing guide (which has disappeared from their website) advised (IIRC) to pat dry the engine bay and its components first, spray Aerospace 303 protectant, start it up (don't forget to remove the foil first!) let it run for a couple of minutes stationary and go for a drive so that any water dries out.

Sounds like a perfect way to create an electrical short. Water and electrics the damage is done the second the circuit has juice flowing through it.

That's why any electrical connections and contacts need to be covered before washing.

@lockheed has a very clean engine bay. I’m sure he would be willing to share his process.

I use a pressure washer but it has an adjustable pressure; I normally protect the tmic and alternator.

All the OEM connectors are waterproof. Engine bays do get wet.

A tried and tested method for over 20 years
https://cimg0.ibsrv.net/gimg/www.sco...5d1d658a3d.jpg

Don, this is to do with your post, i looked up that MC2 Multiclean as i thought that sounds interesting, that didn't half open up a can of worms and had my searches going off in all directions as apparently other users were saying that the MC2 Multiclean which is recommended in that how to clean your engine bay instructions is actually another product where people were saying its re-labelled Viro-Sol.

Is anyone still using Viro-sol as you can still buy it as those instructions above were from around 2006 ish.

https://www.citrus-cleaning-supplies...+326/871144408

https://www.thecleaningwarehouse.co....aser-169-p.asp

I’ve hosed my engine bay loads of times without a problem!


https://cimg4.ibsrv.net/gimg/www.sco...873d8b95a.jpeg

covered only air cone filter and fuse box for piece of mind, used Holts engine bay cleaner and some brush,used hose with water thats all
https://cimg1.ibsrv.net/gimg/www.sco...f06b14ff3b.jpg

i need to paint manifold and get rid of front mount

Now that's a pretty engine bay.

thanks mate

I pressure wash my engine bay every couple of weeks because I’m a complete tart! I use a bag to cover the air filter and that’s it. Just make sure you don’t drive water into the electrics and then run the engine to dry it off, never leave a wet engine as that’s when you see problems with your electrics. I’ve done this for many years on many cars and never had a problem.


https://cimg5.ibsrv.net/gimg/www.sco...8241889ee.jpeg

exactly this! I even shut my bonnet on the latch when it’s running to give it a little steam clean aswell

Wax Wizards engine bay cleaning "method" was around long before 2006 and like many things cleaning products come and go "in favour".
AFAIK Mark back in the day was a rep for Swissol (now Swissvax) who put together various products for car club members to sell on the side.
The cleaning "method" is still sound whatever products you use. Any good citrus based cleaner would substitute for MC2Multiclean and if it was 're-labelled Viro-Sol', it was pretty good.
Again the "protector" mentioned was most likely 303 aerospace protectant or similar.

Salsa-king also likes to spray...........
https://www.scoobynet.com/members-ga...ngine-bay.html

The method certainly hasn't done any damage over the years
https://cimg5.ibsrv.net/gimg/www.sco...1a0033ec8c.jpg
https://cimg6.ibsrv.net/gimg/www.sco...3c6a12cb53.jpg


https://cimg8.ibsrv.net/gimg/www.sco...aa5cd7a721.jpg

Used to my pressure wash the engine in my scoob lots of times; never a issue. But if you use a cleaning solution that contain degreasers (most of them do) Just make sure you apply some sort of protective laquer/wax after otherwise metal parts corrode from the salt spray when used in winter.

Common sense of course; Fan jet, not pencil jet, never closer than 30cm and don't directly aim under the fuse box or into the cooling slots of the alternator, take care with intercooler etc.



Now, other cars don't tolerate water; VW VR6 only has to have a sniff of water on top of the engine and it gets down into the spark plug holes and knackers the coil packs. Yeah, I did that....had to heat cycle the coil packs upside down in the oven several times to get the moisture out of them (when engine got hot the steam was forced up inside them).

The pressure cleaners are usually not bad for cleaning the engine’s bay too, but you need to be careful. It is better to cover at least the air filter and the fuse box before starting.
Also, I would recommend using a cleaner with adjustable pressure and using the lowest pressure possible. It will prevent the cleaner from deteriorating the paint or breaking something inside the car. I have seen professional pressure cleaning guys do that before cleaning the car’s insides. And you will never be able to reach the best result without using a brush and a sponge to clean the places with tough dirt or the places where it is not safe to use a pressure cleaner.

Plus as mentioned above the alternator. I found engine degreaser to work well, then wash off with bucket of water.

https://cimg6.ibsrv.net/gimg/www.sco...67dd33a380.jpg
I use auto glym machine cleaner, agitate with a brush and hose off and then spray a liberal dose of wd 40 and then wipe off. It keeps clean for a few months but gathers dust eventually.... Just in time to do it again. I figure the wd 40 keeps the aluminium parts from electrolysis and the steel from rusting, and it has for the last 6 years. I take the air filter off and throw a plastic bag over trumpet.

I can understand why people want a clean engine bay, and a local near me is always jet wash blasting the engine bay in his Aussie monster V8.
Will ask his technique, but doubt I will have the bottle/ want to take the risk!