PSA: Saw a guy pressure wash his engine bay at a self-serve car wash in Portland

I was at a Splash and Dash last Saturday and some dude just blasted his whole engine compartment with a pressure washer on full jet mode... he didn't even cover the alternator or the intake. Almost started his car right after to "dry it out" like it was no big deal. Has anyone else seen someone wreck their electronics this way?

4 comments

4 Comments

nguyen.angela1mo ago

That pressure washer story is wild. Totally agree with @the_max that water gets trapped in connectors for way longer than people think. Dude probably fried a MAF sensor or ECU for good measure.

hannah3201mo ago

Oh man, this is a classic mistake and I've seen it wreck so many cars (including a buddy's old Civic back in the day). The alternator might survive if it's sealed well, but connectors like the MAF sensor and ECU harness are the real weak spots. Best bet is to use a garden hose with a gentle spray, cover the intake and alternator with a plastic bag, and let it air dry for at least an hour before even thinking about starting it up. If you absolutely have to use a pressure washer, keep it on a wide fan setting and stay a foot or two away from anything electrical - that narrow jet is just asking for trouble.

smith.nancy1mo ago

Did you ever hear about the guy who pressure washed his engine bay and then couldn't figure out why his car started idling like a lawnmower? He dried everything off, checked all the fuses, and it turned out the water just pushed a bunch of dirt and grease into his throttle body, gumming up the whole works. Spent more time cleaning that out than he ever would've just scrubbing it by hand.

the_max1mo ago

Whoa, hold up. I actually read a forum post from a mechanic a while back who said the same thing. He called it the "car wash special" or something like that, where people just blast everything and fry their sensors. The worst part is, the guy probably thought he was doing a good thing, getting all that grime off. Once water gets inside a connector that's not sealed right, it can take days to really dry out, not just a few minutes with the engine running.