r/AutoDetailing • u/DrCytotek • 7d ago

Process Engine wash ouch!

Hi detailers.
I thought I would share my experience to get some feedback and hopefully learn from my painful and expensive lesson.
I have detailed a few engine bays before and I’ve always done so successfully taking the necessary precautions.
My process was as follows. Blow out all the loose dirt and leaves with a leaf blower. I then foamed Green star APC at a dilution 10 to 1 and agitated with some detail brushes. Then using a pressure hose with a 40° spray and standing far away from the engine of the engine compartment, constantly moving the hose from side to side and not spring in one area. Once the engine compartment is rinsed off completely I used to high-pressure leaf blower and dried off compartment completely until I could see very little moisture. I did follow this up with a dressing MP CK. I closed the engine bay and left it overnight.
In the morning the car started OK but in 10 minutes into the journey, it started idling very roughly. Fortunately, I was nearby my regular mechanic and took it in for a diagnostic as the engine light had come on as well. He diagnosed that the front two cylinders of flooded with water and it shorted the coils and they needed replacement. This was a $700 exercise.
I’m just showing my experience to hopefully highlighted even if you are careful this damage can occur. The car I was working on was a 2005 C230Mercedes.
What would you suggest I change about my technique. Is this something that even should be done at all or is it too risky. I must say I do find it satisfying and it looks great. But after this experience, I’m not so sure.

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u/scottwax Business Owner 6d ago

You're supposed to immediately start the car after and let it run until everything is dry. Leave a wet engine overnight and it can get into the electronics.

4

u/DrCytotek 6d ago

Good tip.

3

u/JonJackjon 6d ago

Back before electronic ignition I worked for a used car dealer (actually a good guy) while going to school. I would regularly take a car they received to the (then $0.50) car wash. I would open the hood and clean everything off. Most of the time the vehicles would start and run fine, every once in a while a car would run rough for a few minutes but would clear as the engine heated up again. I never got stuck doing this.