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Just a warning to any 740IL owners regarding car washes, rain , and blown engines.
I have replaced two engines in the last 6 months. One engine blew a rod after going through a car wash, the second engine blew a rod after a sitting overnight during a rain storm. We thought the first engine was blown because of water getting into the intake via upward undercarriage spray at the carwash. On my 1998 740il the air intake is located at a faily low point in the engine compartment. The cause of the blown engines was not the intake but drain holes being clogged in the compartment located below the brake booster. Located below the brake booster are fairly small drain holes which can become easily clogged with leaves and other debris over time. If clogged, the compartment can quickly fill with water during a carwash or rain since BMW designed water from the windshield to flow into that compartment. The booster is vacuum driven with a vacuum line going from the engine to the booster. Once the compartment is filled with water, water can make its way through the vacuum line into the engine! Result, a blown engine! If after a rain or carwash you push on your brake pedal and they feel squishy or odd, DON"T START YOUR ENGINE. Check the compartment under the booster to make sure water has not gathered. I have had my mechanic enlarge the drain holes to make sure I don't have the same thing happen again. I also make it a habit to check the compartment before I start the engine after a carwash or heavy rain. I also check the drainage by putting a hose in the compartment to make sure water drains properly.
 

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driving my marclar
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First of all you must respect your 7 series and not take it through a carwash...ever. It is a vehicle meant to be handwashed only. Secondly no car wash will cause any sort of engine issues in any BMW. I have driven one of my 7 series through a Rain storm through Kansas over 400 miles with no problems. From what you've said it sounds like your 7 sees no maintenance and no proper care.
 

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Funny, I too thought of a tremendous rainstorm in Arizona on the way from Las Vegas to Sedona one time. The rain came down so hard, and bounced back up so high that it was like driving through a swimming pool. I dared not pull over lest someone not see me and plough into me, so I kept moving at a less spirited pace. Lightning flashed and thunder crashed all around, yet I kept moving.

That was about a year and a half ago, and the engine has still not blown. Maybe my drain holes were not clogged.

jake
 
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