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proautotech, Auto Mechanic
Category: Car
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Experience:  College Training. Current Lead Tech
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Smart/Mercedes-Benz Smart Passion: what causes a cylinder leak

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what causes a cylinder leak down?
Thanks for trusting us with your problem. I have trained in the automotive field and currently work as a lead technician. I will be helping you today

This is a bit more difficult since they already did the repair. They replaced the entire cylinder head which could have been several different things.

Burnt or bent valves will cause the condition. Bad headgasket will cause the condition it can also be related to bad cylinder rings.

Since replacing the head fixed the problem this leaves it to be withing the valves or headgasket.

For a vehicle with this low of miles I suspect a defect from the factory as nothing in 20k should have caused it. This is caused from engines being worn out timing jumping things getting dropped down the intake when doing a major repair.

Hope this helps. Please take a moment to leave a positive rating.

Customer: replied 5 years ago.
That's all helpful information.

20,000 was when the service engine light came on, I had it checked out and was told it was just a "spark plug misfire". I left, and a few weeks later the service engine light came back on. I went in, but at that time the mileage was over 24,000, which is when the warranty ends on this model car. At that time they said it was a "cylinder head replacement" job, and charged me $5,000 for the repair.

Ulimately I wanted to get an expert's opinion on HOW they hell this happened to this car, and if it was my fault AT ALL?


It was not your fault in anyway. This is a defect in the product. I would suspect being that close somebody should be working with you on this repair as it is indeed a defect.
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