Why do engine make knocking noise when cold started?

What is your question?

My Tl make a loud knocking sound when I first start it up in the morning or after being parked for at least 6 hours. (summer or winter) After the engine is warm the noise stops and the engine runs like when I first bought the car 4 years ago. Do anyone know what's causing that to happen?

What makes this problem better or worse?

It's better when the engine warms up

How long has your 2007 Acura TL had this problem?

for 4 months

Robert51 in Charlotte NC

Sep 13, 2017

1 Reply

Popular Answer

casey40510on Sep 14, 2017

Hello, Depending on the duration, intensity, speed, and pitch of the knock, there are many things it could be. Does it last until the engine is fully warmed no matter what, or does it go away after a certain amount of time? Is there something you can compare it to, like a clattering or banging a hammer on concrete?

Robert51on Sep 15, 2017

Yes it last until the engine is warm, then it go away. It's like a clacking or grinding sound, almost like if something was touching the fan, and it gradually go away as the engine warms up until it's running smooth.

casey40510on Sep 15, 2017

I think you may be dealing with engine sludge. It blocks passages when oil is cold, but hot oil begins to penetrate through the mess. I'd recommend having the engine flushed and the oil changed, but it's better to identify if that is the issue first. If you notice globs of oil inside the oil fill cap, or if you can see that there is significant oil build-up when you look inside the valve cover where the oil cap comes off (flashlight helps), I'd run the flush. Also, if you know the oil changes have not been done on time or that the wrong type or grade of oil was used, run the flush and change the oil and filter before looking for other damage.

Robert51on Sep 18, 2017

Thank you, I'll try that and let you know if it still makes noise. Thanks again

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