I have a 99 4.6L with 152K, would it be better to use a lighter weight oil 5-20W? Currently using 10-30W and its burning a quart or a little more every 3000 miles... I just wanted to know if it would run a little better.

 

Actually, you should be running 5w30. Especially with cooler weather coming. The 5W will get to the top of the engine quicker on start-ups.

 

Thats what I figured, lighter weight oil would help on the start up.

 

Cant go wrong with 5w30. My truck burns about a quart every 5000 mile changes on a steady of 5w30.

 

i use 5w30 on the 5.4 motor also. has 150k miles-- my preference also.

 

I had a 55 gal drum of oil for my F150 Diesel (20W50). I decided to try the oil in the 4.6 Ltr...... Not a good idea. It had zero oil pressure. Immediately changed to the 5W30 and had normal pressure. I will stay with the recommended oil from now on!

 

right on my dipstick it says 5w20. 2003 4.6

 

I thought most Fords, since the modular engines came out, were to have semi-syn 5W-20 as well? What happened to all those discussions FTE'ers had about it?

 

On my 97 the owners manual and oil cap say 5w30. When I worked at a dealership one of the mechanics told me that it was changed in 98 cause the 97s were having oil related trouble due to the 5w30. I dont know how true that it cause my truck drank 10w40 for the first 90000 miles and when I bought it I started using 5w30.

 

At 160k miles, my 97 got it's first oil change by me, and likewise has received its first serving of Mobil 1 5w30. I'm watching for leaks, and I'll see if the engine likes the stuff or not. It wasn't using any noticeable quantity of oil since I bought it.

 

wow that mechanic doesn't have a clue. The 4.6L was built for a thin oil due to its tight tolerances. 5w20 was brought on the scene to help the trucks meet CAFE standards.