Summers22

iTrader: (2)

For your sake I hope that took care of it. Yes, they are picky about oil as you just found out.

4.6owner

Not only are they picky about oil and filters but the oil change intervals as well. I have several 4.6 and 5.4 modular motors and they don't like extended oil change intervals and they don't like anything other then Motorcraft filters. Ford asked a lot of the oil, pump and oil system in these motors (to much in my opinion).

iemmanuel

After my truck reached 100k miles, i started changing my oil every 5k, now I'm at 185k. think I can take off 10k miles with 10w-30? 90% this truck is work and school

4.6owner

If it has worked for you this far I have to ask why change it? I personally wouldn't but it depends how you drive too. I run mine hard, uphill 80 mph runs unloaded, tow a 7k trailer and off road frequently. YMMV

iemmanuel

Now the truck sounds like diesel when its in low rpms like at the red lights and stop signs or when idling. But when I give gas the sounds goes away. I brought it in the shop today and my mechanic told me it could be vct system, timing.

Ill update when I get the answers.

There is no code showing, or engine light on.

nddragon01

Diesel sounding is usually caused by broken studs mounting the manifolds to the heads if I remember correctly. Might be worth checking them out as well.

Summers22

iTrader: (2)

Dieseling sound is because his timing system is toast.....

BadFish523

Yup diesel sound at a low rpm is a timing issue. Manifold is usually more of a ticking.