Do you power wash your engine compartment?

My dad used to run the hose every once in awhile to a hot engine bay. Never had a problem over some 20 years. Cleans it up real nice. Then he did that to my 2 year old corolla. The car drove really rough the next day. I took it to the dealer and they said water got into two of the cylinder hoses. $10 to replace the hoses and $190 to diagnose, dry, and install the wires. My dad stopped washing engines bay.

 

Yup. Dad didn't have a $4000 inverter and high voltage under the hood either.

 

Make sure all of the connections are tight first and all of the caps are closed, and dipsticks are pushed in.

I use simple green or super clean, mixed 1:3 and a brush to agitate surfaces. A garden hose is usually sufficient unless you have some oil leaks. As long as you aim the direct spray away from the spark plug tubes or dipsticks, you should not have a problem.

As usual, it is all about proper technique...

 

I am sometimes amazed at the poor advice here. NEVER EVER run a garden hose under the hood of a Prius! Far far to much water! I have been power washing a Prius (2 different onesnow) since2006. No problems ever. A garden hose puts out more water in 30 seconds than a power washer does in 5 minutes. Be prudent. Keep the nozzle back a ways and use your head a little on where you aim the thing.