Its not a cosmetic thing they don't clean the out side of your enigne they clean the inside parts LOL. If they clean the fuel injectors than that's is fine I clean mine once a year. they sell this stuff called sea foam its amazing I have a 15 year old car with 175,000 miles with a V6 that still gets 20 MPG with mostly driving around town. But if they want to flush the oil pain out than yes this will mess up your engine especially if it has high mileage. What happens is that the engine flush will dislodge allot of the sludge that has build up on the bottom of your oil pain over the years and it will send it to the oil pump and clog it up which will starve the engine of oil and damage it which will cost you thousands to have fixed. if you want a clean engine than switch to synthetic oil it has the ability to clean the engine much better than regular oil and you will also see an improvement in gas mileage.
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Elektrofahrrad Pedelec
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