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Q: Car not starting after overheating

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My car overheated while I was driving it to just below the redline. I got home, and when I went to replace the thermostat, the car won't start.

Hello, when you say the car won’t start, is it a crank no start or does it not even turn over? If it wont even turn over, remove all the spark plugs and see if it spins over after that. if it doesn’t, and you hear the starter engage, you may have to see if the engine will turn over manually with a ratchet and socket at the crank bolt. If it doesn’t turn over manually with the spark plugs removed, the engine is internally damaged from possible hydrolocking. There is a good chance that you have a blown head gasket and is not letting the engine build up compression, or you have water in a cylinder. Pull the engine oil dipstick and see if it looks like chocolate milk, if it does the the head gasket is blown. The head will have to be removed and surfaced to be sure they will seal up correctly to the block. The cause for the overheating still need to be determined also. You may need the aid of a mechanic to diagnose the no start and the cause for overheating.

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