Engine clean/wash

[MichaelInChicago]

Is it ok to clean/wash the engine?

I have had it done by detailers on other cars I have owned over the years and never had a problem but I have heard and read that it should never be done.

Which is true?

If it is ok to do, can I do it myself? What would be the best product to use?

Thanks

[ezmaass]

Some amount of water is natural to get into the engine bay, but where it gets bad is when people take hoses and pressure washers to their engines. There are more and more electronics, wires, connectors, etc, hiding under the hood these days - all of which should be well protected from water, but over time, of course, seals break down, little cracks form that allow vapor/water to get in, etc, and spraying a ton of water in there can then turn bad.

I'm not a fan of spraying water into the engine bay for the above reasons, but if you do, you probably just want to go about it lightly, finding and taping off/covering sensitive areas. Alternatively, products like Chemical Guys' waterless wash are great for removing grime without the need for water. You're just wiping it on and off.

[Opie55]

I washed mine not long ago. You just need to know where stuff is and not direct water at them.

[TON-III]

I've managed to wash my past engines with 'raining' water and brush just generator protected, maybe BMW will tolerate that too ?

[DaveS86]

I usually put a bin bag over exposed connections and then give it a nice degreasing on low pressure on the Karcher, never had any problems on any of my cars

[Opie55]

I put a bag over the alternator and the air intakes because I remove the filter housings, but that's it. I'm careful not to spray the two ECUs but they are easy to avoid because of where they are. When done I use compressed air to blow out the water that pools in the deep recesses where the two oxygen sensors are behind the turbos. Still a hard engine to clean because of so much stuff under there. I've never seen another car where it is so hard even to catch a glimpse of the belts. Looking forward to the day I have to change those.

[thebmw]

Pictures of what you cover would be great!

[mudpaw]

I have wash engines on all my cars for the past 30-40 years. Never use high pressure water on any electrical component.

Nothing like an engine compartment clean enough to eat off of.

[JBF650]

I must say I’ve been terribly guilty here..... I’ve always regularly washed my engine bays in all the cars I’ve owned. I cannot think of any cars I’ve had that I’ve caused issues. In older cars yes I use plastic bags around vulnerable areas and newer ones I avoid the obvious electrical stuff. I use a light detergent and spray into the hose nozzle which is very mild and gentle and washes the engine and engine bay down nicely. As advised , be careful not to aim high pressure water at electronics et al. But appreciate most under hood will get pretty wet.... I usually ensure the engine is warm , not hot , just warm so evaporation assists the drying process. Then with an old chamois dry off the surface areas. Looks great and clean as a whistle! Say once every few months is ideal.

[Opie55]

And I have to say that the engine compartment on a 650 (and presumably 640s) is sealed better than any car I have ever owned so it stays pretty clean. My X3 is the opposite - if you wash the engine it's covered in grit in 2 days.

[thebmw]

If anyone can post a pic of areas they cover or avoid washing, that would be great. There are wires and connectors everywhere. Is the X5 with the N63TU the same layout for washing?

[Opie55]

I simply put a bag on top pf the alternator and just kind of loosely push it around the sides, and then avoid directly spraying it. And I put plastic with rubber bands over the the air intakes. That's it. Other than that, I just avoid spraying the two ECUs (computers). On the N63TU they are flat silver rectangular boxes at the front corners of the engine bay (one on each side) with a bunch of big electrical plugs going to them (and two tiny coolant lines). You can see them in the pic above. Since they are so far from the engine itself, they are easy to avoid.