Can you safely pressure wash an engine?

[Paladin]

I was thinking of pulling out my pressure washer and spraying down the engine while I'm in working. I do it all the time on my cars but is there any reason why I can't do it on the bus?

Just want to make sure I don't do anything to damage the spark plugs! I went to Pep boys and asked for spark plugs and wires for a DD 8V71 and they had to look them up for me.


-Dave   

[Dallas]

Be careful washing your 8V71... if you use hot water it will shrink and you'll end up with a 6V53 when it drys.

[HighTechRedneck]

More of a concern than the plugs and wires is to be sure you cover the distributor cap with plastic to keep water out of it.   

[jjrbus]

 If you remove the air cleaner, be sure to rubberband some plastic wrap over the carb!!!!

[busnut104]

It will not hurt to pressure wash you eng. Make sure it is cooled down and watch the excess pressure on certain areas.

[Paladin]

Which 'certain areas'?

[Dreamscape]

When I pressure washed my 8v71 I ended up with a problem, this is because I was very green at the time and didn't know much about this beast. This was back in 2004, had the bus for a couple of months.

I washed everything real good and stayed away from any electrical and anything else that could be damaged. I fired her up and went for a test run. Everything seemed fine, this was on I-5 in Santa Clarita Ca, all of a sudden I could feel the power drop and looked at all my gauges and mirrors. I was horrified, tons of black smoke was coming out the exhast. I had all kinds of thoughts going through my mind, mostly $$$$$$ signs. I pulled over, within 2 minutes the CHP pulled in behind me with lights flashing, again $$$$ signs appeared. He said you have 30 minutes to get this bus off the shoulder, then he proceded to call a tow truck. I pulled up the engine hatch in the back and was looking around, found that the emergency shutdown lever/rod was flipped. No solenoid was there, only the lever. I didn't even know at the time what this was all about. I flipped the rod over, tied some wire to hold it open, fired it up and noticed no black smoke and plenty of power. Boy was I glad, I told to officer that I had it under control and went to the nearest exit ramp and dissappeared into the sunset! Of course he said, what did you do, I said that I fixed it no problem, smiled and away I went. I had not idea what I was doing or what I did until later. At least it didn't cost me anything, just my pride.

Just be careful,

Paul

[grantgoold]

Funny, when I power wash my 6v92, it seems like for at least a day or two it swells to the 12v92? Is that supposed to happen? Should I check the coil?

Grant

[PP]

I'm still waiting for the swelling to go down. But FWIW, almost all diesel manuals advise against pressure washing their engines. Diesels and water do not mix. As an idiot, I know these things, PP

[rcbishop]

  ..amazing, that posted above.....I pressure wash my Cummins often.  amidships, pancake style and no problems that I know of for several years. The local Diesel repair facility does it as well...on my engine. 

FWIW , eh Henry?

RCB

[Barn Owl]

I pressure wash mine and the facility where I work pressure washes their whole fleet.  In one of my past jobs I called on a customer that cleaned up repos. I saw them open up a Caddy's door and pressure wash the entire inside including the dashboard! I asked what are the side effects and they told me that something's might not work for a day or so but by the time the car made it to auction it would be OK. Not something I would do to anything I owned, but interesting I thought.

[JohnEd]

Let me make a suggestion.  Before I pressure wash my cars at the car wash I make certain they are warmed up nicely.  My cars have plugs and at least half the time I get a rough running engine after washing.  Sitting with the hood up it dries off in a few minutes and even if I couldn't get her going at first I have a rapid recovery.  I also leave the engine running if I am not familiar with it.  That way if it dies I know what I was "squirting" when it died and where the problem might be.

I make a point to do my wiring.  12 or 24 volts isn't going anywhere through water no mater how much soap it might have in it.  The thing to avoid is "relays" and anything that needs oiled regularly that will bind if dry.  And stay away from the warp drive.

HTH,

John

[Len Silva]

Funny, when I power wash my 6v92, it seems like for at least a day or two it swells to the 12v92? Is that supposed to happen? Should I check the coil?

Grant

If it stays swollen for more than 4 hours, contact a professional.

Len

[buswarrior]

Mechanics here in big transit won't even look at the engine unless it has gone through the steam jenny room first.

Cleaner hands, and lots harder to contaminate open stuff if there is less dirt around.

Also, less grease and oil, less fire risk...

keep it clean!

happy coaching!
buswarrior

[TomC]

At least on my engine set up (8V-71 with V730) with the D50 Delco sealed alternator, pressure washing is not an issue.  If you have an electrical control box like I do that has the rear engine control switches on it, I would avoid shooting water on it.  But as far as the engine and transmission go, they are almost completely sealed except for the breathers.  You got to realize that with a rear engine you get lots of road dirt and water being thrown up into the engine when driving-so everything is designed with that in mind.  Also, a dirty engine tends to run warmer since dirt and grease are good insulators.  Great in winter, not so good in summer.  Plus it's just nice to have a clean engine that is also painted nice when you inevitably open the door to show your friends.  Good Luck, TomC