Noisy Valves on 2004 Altima 2.5

[boxcab]

I live in a cold climate. My 2004 Altima has 40,000 miles on it. It is a 2.5, automatic. When the car is 'cold', the engine sounds like a diesel, and this for a good 10 minutes into the drive. The engine oil level is fine, I use regular 5 W 30. Is this ''knacking'' sound adjustable? Are these loose valves? Is this part of regular maintenance or does this signal another more lethal ($) problem to come? If it is just a valve adjustement what is the usual time requirement?

Louis

[driftingmy240sx]

the only way to adjust the valves is to measure the clearene between the valve and lifter then remove the lifter and read the size of the lifter on the other side then enter those two numbers into a formula to se if the clearence is correct or if you need to go to a thicker or thinner lifter.

i work at a dealership and temps outside have been 32 deg f at best lately. its pretty common to hop into a car that has a 2.5 and hear lifter noise. without being present for your actual symptom, based on my experience i would say you are okay since the noise does go away.

if you do feel that the noise is a problem you car should still be covered under the powertrain warranty.