Does anyone know if the "official" stance from Mercedes-Benz as to washing the engine bay? Has anyone experienced issues after washing a cold engine and immediately starting and driving the car to operating temperature to dry it off?

I had a 1992 Corvette ZR-1 (4-cam 32-valve engine) back in 1995 and after washing the engine the starter motor had water enter into it and it had to be replaced (it was located underneath the upper intake in the valley pan). Since then, I have been very reluctant to wash an engine and typically just wipe them off as best I can with a towel.

Any experiences/input?

 

I've washed the engines in all my cars and motorcycles for many years, but with newer cars I think one has to be more careful of the electronics.

My current method is to get the engine warm, spray it with solvent (Simple Green), rinse with my power washer on the gentlest setting, start the engine and let it run for a while so the heat helps dissipate the water. I don't cover anything, just avoid excessive wetting of any electronics. I think the power washer rinses clean without getting excessive water into the engine bay, and the stream is so gentle it doesn't seem to penetrate where you don't want it.

The only time I've ever had a problem was with an Acura Legend, which would throw an O2 sensor CEL necessitating a reset.

I don't know M-B official policy, but my guess is "don't do it yourself, bring it in to the shop and let us clean it with Liebfraumilch".

 

honestly, unless you are leaking something, or are planning on going to a concours, why bother?

Id just clean the engine cover and maybe wipe down the other plastic parts. No real need to get the soap and water out, given the lower body tray and the huge engine cover.

 

Polar Bear, I guess I am wondering why you want to wash the engine? Is it for appearance, or do you think it will improve wear / performance? I would be curious to know if there is a benefit to it, and if so how to do it.

 

It might not be necissary, but a clean engine sure does look nice!

 

I would like to have my engine cleaned as well. I forget what they did last time when I had it detailed because they also cleaned the engine.

 

I have washed engines in numerous cars / motorcycles over the years. The ignition systems have improved so that it is unlikely that you will drown one out. As with most endeavors, the more time and effort you apply, the better the results. Pressure washers will certainly test the electrical systems. Degreaser with moderate hosing is less likely to cause a problem. I would not apply water to a running engine nor would I hose down a motor that has been thoroughly warmed up even though the grease is most easily removed when warm. Obviously, spraying water directly into alternator or starter windings is undesireable, ditto air intakes. There is a direct correlation between age and watertight integrity of the motor. Plastics and rubber deteriorate from heat and age. So if it is a 2008, spray away. If it is a 1973, probably better do that near your home or with a good pair of walking shoes.

 

Somewhere in the manual I think it says to apply MB anti-corrosion to some components before washing the engine compartment.

 

For appearance mainly. I typically like to keep my cars very detailed when possible.

Some say a clean engine will last longer but who knows. I can see where wetting it (as I have witnessed) can do damage in some cases, so I am a little nervous about taking the hose to it. It's not real dirty by most people's standards, just a little dusty.

 

I get my car washed 2x a week, and detailed once a month so I know what you mean.

 

You could always remove parts, have them powdercoated, and show off like I do with my Supra Notice how dirty my firewall and hoses are. This was without cleaning the engine, but powdercoating stays clean, just wipe off!



I don't recommend power washing. Just take simple green or another degreaser, and elbow grease. Spend a few hours in your engine bay (you did bring up this post, so I imagine you are willing to do that), and clean each component by hand. Even if you don't remove pieces, just use a screwdriver covered in cloth to get to those hard crevices/places. Next time you go to a MB meet, pop your hood and wow everyone!

Today's engines have those ugly plastic covers on them, so there's not much to do, so just hand clean all the pieces you can see, and u're good to go! You could even have the plastic cover painted which looks great.

PS, imagine powdercoating/polishing the supercharger on an AMG engine!!!

 

I'd so do it blue, that would be sick.

 

I find that CD2 Engine Detailer does a good job on the plastic covers.

 

I've been hosing off the engine bay pretty much each time I wash the car for many years, and on many different cars, with no issues (I occasionally use soap as well). I do this starting from the day I buy the car. As a consequence, my engines always look like new until the day I sell the car. Not only does it look nice every time I open the hood to check the oil, etc., but when I'm selling the car, a gleaming engine bay definitely seals the deal.

 

I agree and that is my motivation behind doing it. I enjoy a clean engine bay.

I don't care to hose off the W123 300D but thought I would get some input before doing it to the W211.