Y2Kvert4me

I typically hit my engine bay with a pressure washer twice a year...mostly to clean off the framerails, and the nooks/crannies around the a/c compressor. Those are the hard-to-reach areas where gravel and dirt like to accumulate, and there really is no better way to clean those areas.

Never had any problems doing so. But it goes without saying to avoid spraying directly at the alternator and fusebox areas.

Evil-Twin

Many C5's have fallen victim to shorted out Knock sensors , they sit in a pocket under the intake manifold.... it doesn't take much to get under the manifold with any hose or any type of pressure stream... because of this issue GM put out a tech bulletin on building a dam around the knock sensors when they fail due to shorts from water under pressure washing.
I would never use any type of hose or stream of water under my hood...Those who have said there has never been an occurrence, need to check the archives here. There have been hundreds in this forum who have been stranded because they chose to stray off their engine.

Garrett W

Jistari

Yup, says it right on the bottle, not safe for aluminum. I have a bottle in the garage but stopped using it when I found this out.


As far as steam cleaning? Guess it depends on how dirty it is.

Me I usually use two spray bottles (one diluted general purpose cleaner and one straight water) and a few long handled brushes. I just spray whats dirty, brush it off and "rinse" it with the water bottle. If somnething is bad, I just use straight degreaser then rinse.

I can get it very clean this way and havent resorted to hosing it down under there.

Although I havent tried it, I have a friend who finishes by spraying the whole thing down with Armor All, then he just closes the hood Not sure if Im gonna use the armor all but I might spray it with something when Im done next time.

VettesandZs

Go to a car wash, use the high pressure wax setting (can use high pressure rinse), DON'T TURN OFF ENGINE, spray thoroughly, but don't blast continually in one spot AND GO DRIVE IT FOR AT LEAST 30 MINUTES to dry off under the hood. Use this method and you won't have any problems. I have done at least 50 different cars with this method including many C5s and never an issue.

jr3

People would probly be shocked if they knew just how often engines are cleaned this way. If you bought a pre-owned car from a dealer, more than likely the engine has been cleaned with a pressure washer or steam cleaner. Some of them spray purple power on the engine bay then rinse it off with a water hose. Thats done while the car is being detailed to go on the lot.

But BEWARE! This can also cause various dash lights to come on such as CHECK ENGINE light, or ABS light etc..... It can also cost you several hundred dollars if you have to take the car to the dealer to get the dash lights to go off. On some cars you can take the battery cable off and the Check Engine light will reset itself.

This is an easy way to clean an engine bay. But remember there can be risks by making your dash warning lights to come on or produce a skip in the engine as if you had bad spark plugs. Wash at your own risk.

Many cars are washed with no problems. But some do have problems. If you do wash it, be sure to cover as many electrical parts as possible with plastic or something water proof to protect it. Better to be safe than sorry.

tstar

That's the biggest issue with washing the engine bay, the knock sensors. You don't want to force water up under the front of the intake... Everything else is as weatherproof as can be expected.

Having said that I wash mine with a light hose stream but keep the stream off the intake...

Rohan

Not if you have the nice seals that go around the hood

riarms

Ive done mine with degreeser and a hose I never cover anything and keep the car running when i rinse the stuff off no problems

riarms

Yikes, guess ive been lucky then. Ill make sure i do it in my driveway incase something does go bad

Chicago1

So what's the proper way? Hose no hose? Power spray no power spray? No simple green because it will fade polished pieces or no? I'm surprised this hasn't gotten moved to car care section.

03WhiteConv

Degreaser, a toothbrush and a light spray with a hose. No water near the intake in order to protect the knock sensors.

Wipe it down, hit it with some window cleaner and some kind of dressing.

FrankTank

great dealer trickery to get people to come back after they get the car...I can see it now "well that short in your maf sensor and coil pack is not covered by your powertrain warranty"

I've seen them do that too.

dieseldave56

Wow. 44 years and well over three hundred (300) cars I've owned and all were either power washed or actually steam cleaned ( you could buy steam cleaners back then. Some of you remember filling the fuel tank with kerosene and lighting off the boiler ritual). Both the engine and under carriage would be cleaned. Saran warp on the alternator ,foil over the carb and a rag in the distributor. Grab a bucket of soapy water and a toilet brush and have at it. Good to go every time.

I learned long ago to use dielectric grease on all electrical connectors, plug wires, firewall connector, ect. Then dry off all the components, radiator fins, under the manifold, everywhere I could. But I don't start the engine till the next day. Don't recall ever having any issues.

99% of my engines never got dirty enough to have to power wash a sceond time.

dbbspider

I just finished washing the engine bay today. Here's what I did:
1. cover the battery and fuse box with a plastic bag.
2. cover the alternator with a plastic bag.
3. I used a garden hose with a spray gun ( i used the mist and/or shower function) and wet the engine area, i dont spray the battery area as it can be cleaned by hand
4. sprayed the engine area with all purpose degreaser (orange bottle from walmart)
5. Let it sit for 1-2 minutes
6. Rinse the engine area with the garden hose spray gun (make sure to get all the degreaser off)
7. used compressed air to get all the water out of the hard to reach areas
8. remove the plastic bags
9. start the car and let it run to dry everything else
10. sprayed dressing on a rag and wiped down everything I can with it.
11. Wash the exterior of the car.

No problems and it runs fine. Now my dad wants me to clean his 02 S-10 which is filthy.