Can you safely pressure wash the engine?

[thejumpsuitman]

Hi,

I continue to be like a sponge, learning everything I can... 

I was watching some Youtube videos about buses and one scene showed a charter company maintenance clip.  In the clip, they were pressure washing the engine.  Is that advisable?  If so, are there any precautions to take?

Marc

[redbus]

I pressure wash my engine every 2-3 years (25-40,000 mi) with no problem yet.

[Jeremy]

I had a petrol engine steam cleaned once in order to find the source of an oil leak. There was no ill effect other than a misfire for a short while on the way home. I seem to remember something that wasn't firmly attached to the engine got knocked off by the spray as well. The engine looked like new at first, but quickly started going rusty.

Jeremy

[thejumpsuitman]

Seems to me that you would have more potential problems from power washing a gas engine... Moisture in the distributor cap and in the carburetor.  Just wanted to know, is there anything you should avoid spraying on a diesel?

[redbus]

I don't know what you should avoid spraying as I spray below the exhaust manifold.

[ruthi]

We power wash ours fairly regularly, no problems.

[Tenor]

Blast away!

Glenn

[boogiethecat]

My experience?  Pressure wash anything you want to, but NEVER steam clean an engine compartment of any kind !

The difference is, pressure washing simply gets everything wet and it'll all dry out.  But steam goes anywhere it's cold and condenses... it gets past moisture barriers in electrical connectors like nobody's business, and easily wets places that pressure washing alone would never touch.  That's where you run into trouble- steam + electrical system = corrosion in places you'd never guess!  I only had to replace an entire harness once to learn my lesson...

[bobofthenorth]

I'm always nervous about blasting cold water on a hot exhaust, particularly the turbo but to some extent the entire manifold.  Perhaps my concern is not justified but it bothers me anyway so I always make sure that area is the last to get washed.  It gets splashed plenty while I do the rest of the engine and gets some additional cool down time that way.

[robertglines1]

I also use a pressure washer regularly..one thing I do is soak the heavy areas with diesel fuel...it makes the oil and dirt come off better....Not on a hot engine.....also use purple power....on lesser grime. It works for me especially if I'm working with the part...

[Don4107]

Be careful around seals like the crankshaft and fan drive.  Let the engine cool.  Warm is helpful, but not hot. If it steams when you hit it, it is too hot to wash. 

Not a good idea to wash a diesel with an injection pump when it is hot.  The tolerances are so close that you can shrink the housing and the internals stay hot.  Or give it plenty of time for the temps to equalize before you start it. 

The difference between having the nozzle of the spray wand a foot away and an inch away is huge.  If you have any marginal paint it will be gone!

[junkman42]

The big downside to washing the diesel engine is if You get any water in the intake system and start the engine a teaspoon of water in a cylinder will simply destroy very expensive parts.  For those who fly or used to fly aircraft with radial engines a person who turns the mag switches on before 9 blades will possibly see lower cylinders laying in the cowl.  The higher compression diesels like the kubota gensets will tolerate no water in the cylinder period!  I would never use a pressure washer on a diesel just a hose and gunk mixed with stoddard solvent or mineral spirits.  High pressure water can and will cause loss of alternators,starters and can ruin gaskets etc. My two cents.  Regards john

[gus]

I pressure wash my 671 only when it is cold or slightly warm and after a good soaking with Gunk.

The places I avoid are the alternator and starter, especially the alt since it is open for air cooling.

My air intakes are outside the engine comp so that is no problem.

[wal1809]

If you all know anyone in the bio diesel hobby/business then beg them for some de-math glycerin.  It will break down grease faster than any comercial chemical and is enviromentally good.  My wife and I make lye soap and that stuff is the shizzle so far as cleaning.