F150 w/ 5.4l v8. Since I bought this truck it has make a diesel or rattle sound for a few seconds on initial start-up if the truck has sat a few hours. As the truck gains mileage, the noise level has increased and lasted a little longer. At this point a cold start will produce an engine rattle lasting about 3-4 seconds, includes a ticking sound, and thus far has no effect on performance after initial start.
I have seen some TSB's regarding this, but I am still unsure if I need to fix this now, or if it is just a crummy noise with no long term effects. I also do not understand from the TSB's exactly what is causing the noise, and what repair will fix the problem.
I would really like to avoid a timing chain skip and the valve damage that would be caused.
Saturday, December 26th, 2009 AT 10:40 AM