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1996 Ford Taurus Question: why my car knock when cold stop after it git hot

 

Question

8last28word, 3.0L V6 DOHC, Union City, TN, September 17, 2013, 08:29
 Rookie

every morning when it start quits as it warm up

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  • Answer #1

    September 17, 2013, 09:13
     Journeyman

    need to get it to a shop to see if it is an engine knock or an exhaust leak as both can go away as engine warms up.

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  • Answer #2

    Greg's Orange Auto (14224 Answers) , Orange, CA - (714) 361-9386
    globalhelper September 17, 2013, 12:49
     Master

    agree with ford man

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  • Answer #3

    September 18, 2013, 23:49
     Master

    If the car makes noise only when cold then I would check the oil pressure when it is first stsrted and see if the pressure goes up as the car warms up

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  • Answer #4

    September 22, 2013, 17:49
     Technician

    I'm going to assume that you can tell the difference between a knock and an exhaust leak and I have to say also that oil pressure is more likely to go down as the engine heats up because (non-synthetic) oil will become thinner as it becomes warmer which generally leads to lower oil pressure. An engine knock that occurs on a cold engine and fades after warm-up is usually caused by wear on the cylinder walls and is most commonly called "piston slap". Some manufacturers have specified an acceptable amount of time before fade however, this is one of those things that does not get better and indicates possible engine failure on the horizon. If what you are actually hearing is more like a tick or a tap, a faulty lifter may be the problem or possibly even the exhaust leak one of the others mentioned (can you smell exhaust?). This would be located at the exhaust manifold to cylinder head gasket on a single cylinder. A good tool for finding a knock that can be found at any auto parts store is a stethoscope with a thin metal rod on the end of the tube. If you cannot hear any knocking through the earpiece, start looking for that exhaust leak.

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