Question:  I have a 2006 Lincoln mark lt, it makes a ticking noise when accelerating or when i start up, they dealer put in 5w-30 when it should be 5w-20, could that cause the sound, truck runs great ans has good oil pressure, the sound is just annoying.

Answer: No, this small changed in oil viscosity will not cause the noise you're describing in your Lincoln. It is hard to diagnose a noise without hearing it for myself. The noise in your car could either be an internal engine tick or a spark knock noise.

Spark knock is usually caused by preignition inside the cylinder. This is usually caused by using low-grade or low octane fuel If engine that needs higher octane. But it could also be because of an EGR valve problem. I would suggest getting the codes in the computer scanned to see if that leads anywhere.

Next call the dealer and tell them that this noise started right after the oil change. It is possible that the incorrect oil filter was installed, it's low on oil or they somehow damaged the engine by possibly even forgetting to put oil in it taking it out and then discovering there was no oil so they pulled it back in and added the proper amount. This short time could've damaged the engine.