Just changed my oil and now when I drive the car under slight load it makes weird deep-ish slight tapping noise that goes with the engine as I rev. Once I go on to higher rpms(above 1200 it goes away). Car still drives strong any ideas?
My friend told me to use prolong engine treatment and now I cannot hear the noise(or it's really really faint). Any ideas?
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Check your oil level. You may be a little low.

 

Also, check the oil level on a COLD ENGINE like in the morning before it's been started. That will give the most accurate reading.