Pressure Washing an engine - thoughts?

[dazzsaward]

Hi All,

I am thinking about having the engine and engine bay of my car (Mercedes CDI) pressure washed. The majority of the engine is covered in plastic trim and it is beginning to look a bit grubby.

Have you had any negative experiences after having done something similar to your car - e.g. Sensor troubles, electrical issues, etc?

Any other tips on how to minimise any issues would be greatly appreciated.

Thanks

[dingocooke]

My opinion, if you can avoid it, don't do it.

If you need to clean it up tape up/poly bag/cling film wrap any obvious sensitive areas, then hand spray and paintbrush scrub clean with any degreaser cleaner like gunk jizer etc (theyre all the same, parafin is the active ingredient plus perfume..choose by preferred smell or just be a cheap skate and use parafin)

Then wash off with a normal hose; low pressure less likely to get where it will do harm.

Then run the engine to dry it all off, and spray big mouldings like air box/cam covers with silicone to bring back the lustre, and wd40 and wipe off the rest.

[Sea Demon]

You'd be better off having it steam cleaned - pressure washing wont clean the grease etc off, my local hand car wash does it for £5.

[Piepiepie]

Why does anyone want to clean the engine?

If i go to look at a car to buy, and someone had power washed it, im instantly suspicious they are trying to hide something, or have fked something up.

[bqf]

First thought, Don't. Second thought, really don't. How many plastic hoses, easily corroded bolts, fasteners etc are sticking out of your engine? Imagine water being fired at them or worse, STEAM, and consider whether you would be happy for this sort of water ingress to take place on a regular basis - if so, take the undertray off - the rainwater on the roads will keep the bottom of your engine really, really, clean!

Engines are filled with oil, and lubricated. Don't add water.

[Noesph]

If most of it is covered in plastic, why don't you try something like autoglym bumper care.

[Classic Grad 98]

A wipe with a damp (old) chamois does it for me. The chances are you won't do any harm pressure washing it if you keep the lance a good few feet away from the delicate electronic bits. If you do decide to go ahead, either keep the engine running while you're using the pressure washer or start it up shortly afterwards; if there's one thing worse than getting everything very wet, it's leaving it very wet for any stretch of time.

[orhan]

Don't do it I work for a bg roadside assist co and can't remember the amount of times I had to tow cars after engines been washed water in all the wrong places and a lot of electronics damaged due to water Ingres , in short like all others have said don't

[Wacky Racer]

If you really must, use a tin of Gunk traditional spray...(not foam, it's crap), leave to soak for five mins and hose off with LOW pressure hose, after covering over all electrical connections, then run engine to dry off.

[monthefish]

Use baby wipes. A lot less risky.

[Mr Whippy]

I'd just get to work slowly and steadily over the engine.

In practice it takes about an hour to make it look tidy.

I can see the attraction of spraying with a degreaser and leaving then cleaning off, but the natural oils and grease in the engine bay probably help a great deal towards protecting it!


As long as it's not caked from leaks and stuff, just clean off the plastics with some cloths and cleaning solutions.

Dave

[Glade]

I have got water down spark plug wells before - misfires galore!

Getting water out of the hole was difficult enough... needed a high pressure air line in the end.

Water had wicked up the HT lead and little intermittent misfires just kept coming back!! In the end I had to get them in an accelerated ageing oven at work for a few days to dry them out!

Never again!

[dazzsaward]

That's a NO then

Thanks guys and gals - I won't bother letting the guys at the local car wash do it. I will instead just use elbow grease and a damp cloth, WD40 etc.

[kambites]

It's good for an engine to be oily - keeps water away from the metal.

[johnpeat]

I once worked somewhere where they routinely cleaned engine bays with a medium pressure hot washer - and we never once had an issue with a car either then or later (they could have been breaking-down wholesale, but no-one complained).

One thing - they used to do it with the engine running, which I guess makes it less likely water will settle anywhere (vibration and heat seeing to that)???

I always thought it was a bit dumb and - tbh - the results were seldom decent as grease and oil won't move without some solvent action anyway? I think their main aim was removing the fine dust you can't avoid getting in paintshop/bodyshops - for which an airline would also have worked, I guess...

[CampDavid]

Remove the plastic bits and clean them off the car. Don't touch the oily bits.

To be honest, I can think of better things to do

[dazzsaward]

Piepiepie said:

Why does anyone want to clean the engine?

If i go to look at a car to buy, and someone had power washed it, im instantly suspicious they are trying to hide something, or have fked something up.

^^^^^I agree. However, I will be putting the car up for sale over the weekend and thought it would be nice to have a nice clean engine bay as the majority of people think that is a good indication of a well maintained car

In the current climate and after reading some of the other threads about how much of a struggle it is to sell a car these days, I was thinking along the lines of "every little helps" and wanted to hedge my bets with a clean engine bay. Even though my car has a full main dealer history and a folder stuffed with receipts, you would be surprised how many people take minimal notice of this and go all "doolally" over a clean engine bay.

[kaf]

I,m going to go against the flow here.

I totally understand and agree with what has been written, there is a risk of water damaging components and there is a need to be careful.

However, I like a clean engine bay, hate it covered in dirt and mud.

Every few months I take a pressure washer to it, but from a decent distance around the engine and electrics. Get them wet, quick wipe over painted areas with detergent, blast the painted bits with washer but much lower pressure on the important bits.

Most cars electrics are fairly well waterproofed and should be Ok, run the car straight after to dry off.

BUT the caution advised by others is very valid and you do need to be careful

[aka_kerrly]

In my opinion there is a difference between a clean engine bay that has been maintained to a high standard and one that has been pressure washed.

I'm not a fan of pressure washers, a pot of degreaser and a paint brush to get in all the nooks an crannies and a light rinse.

[XG332]

We quite often pressure wash our Radicals after wet races with care taken around electrics.