Originally Posted by mrny
When my 05 Liberty 3.7 is shut down and I restart when it is still warm, the lifters sometimes are momentarily noisy. I wonder if I can switch from 5w30 to 10w30 for a trial . My manual says 5w30 I don't think it would hurt anything .
Umm yeah, it can actually. Your oil pump is designed to pump oil of a certain viscocity. Too thick, and you can cause damage to the pump, and the relief valve. 10w30 will be thicker cold, and about the same viscocity warm as 5w30, so with a warm engine, you gain nothing, and with cold starts, you will aggravate your problem, with an engine starving longer on start up. Valvetrain clatter is not a sign of needing thicker oil, its usually a sign of lack of proper oil change intervals, and sludge deposits building up. One more thing, 10w30 has a different additive spec, and the needs of your engine will surpass what that oil can deliver.