can I use pressure washer to wash the engine bay?

You can probably block off the important electrical parts with plastic and tape, but it would still scare the hell out of me. There are a lot of electronics on modern cars that can be damaged by moisture. Unless your car has an oil leak that has really buggered up the engine bay IMO it's best to leave it alone.

 

Remember these are anecdotal replies, but I think you would be ok running a open ended hose to wash/rinse off engine cleaner but not a pressure washer or even a spray attachment for the hose.

How dirty is it that it warrants washing? IMO the belly pan does a remarkable job keeping the engine bay clean.

 

Only if your wife says it's OK. Then you can blame her if something goes wrong.

 

I would not dare try it with a hybrid. There are big high voltage cables with their attendant sockets/plugs, the inverter, as well as an electric air conditioner and water pump. Water infiltration into any of these things could result in problems.mnot worth the risk without a compelling reason in my opinion.

 

I don't know about a pressure washer but a hose certainly wouldn't present any more issues than a hard rain at speed. Don't get crazy with it and you should be fine. I've washed mine before and had no issues.

 

Living rural I use a fire hose but reduce the pressure by not using fully open nozzle. I also use compressed air to dry the electrics off afterwards. However since plastic seals shrink with age and my Prius is 2010 with 100,000+ miles i am now covering some areas around the fuse box and inverter with plastic bags and gaffer tape. Mostly I am just washing off dust and rodent droppings.

 

I recall specifically reading in the owners guide that washing under the hood of the prius is not recommended due to the high voltage parts. I thought this was bogus though since I like powerwashing under the hood of my car once a year with my old impreza. With that being said, I used a degreaser and then powerwashed the impreza. I noticed that the motor running the belts and bearing noise etc got a little noisy after I did that.. Maybe the degreaser removed all the necessary lube to keep everything running smoothly.

I used to work in the detail department of Lexus and our team always powerwashed under the hood of all the new cars before delivery. This included the RX400h which is a hybrid as well. As far as I know, there were no problems that ever occured. But then again the lexus' engine bay has the major parts covered by plastic more so than the prius.

Just to be safe, I would never powerwash the engine bay of my prius. If you are selling it, maybe it won't matter as much to you

 

Unless it's very dirty, I would recommend selling it as is. Potential buyers would be able to use common sense to accept normal amount of dirtyness. Some buyers will like a newly washed engine compartment, but there are buyers like myself who will question why you cleaned it. When an private owner cleans the engine, it raises more questions than a clean-engine car from a dealer because that's what dealers do.

I supposed you can do it, but only if you know what you are doing and which areas to avoid, such as electrical connections, ignition coils on the valve cover, belts, inverter, etc.

Whatever you do, I would not recommend steam washing. Steam will enter electrical connections easier than water and over time will cause rust.

If it's just surface dust, I would use a vacuum and take my time.

 

You can buy engine cleaning foam spray that can be washed off gently, no need to power wash. There is always risk with water getting in places it's not supposed to go. My nephew once fried ECU this way (in his car, not prius).

 

Er, am I the only one who thinks:
"bare hand + wet towel + 200-540 volts" = "TROUBLE" ?
Right here in River City!
And that starts with T and that rhymes with P and that stands for Prius!

 

That's a little odd...: did you ever leave the oil filler cap off, have something disconnected? A spill? Maybe just an overenthusiastic mechanic with spray lube. It sounds like you have some sort of baked-on oil.

I had the hood up to check oil level yesterday. We've got just over 40000 km, pretty low. But it looks very clean. About a year back I went over what I could reach with the wet-dry vacuum, paint brush or two, and a cat-tail style brush in harder to reach corners. First I vacuumed, then switched it over to blow. Still looking near showroom condition.