Synthetic oil, Tech bulletin -air box noise
 

Does anyone know what brand of Synthetic oil most ford dealers use? also my Excursion is in the shop. i noticed a shuddering or rattling noise on Decel. only. Service manager called today and told me (also read to me part of a tech bulletin) that some models experience this under deceleration. noise is coming from the air box. no retro fit or repair is needed . anyone heard of this? also, Turbo checked out fine.

Sounds like what you are hearing has been commonly referred to as turbo fart. The 6.0 has no waste gate and if you let off the accelerator under certain circunstances the excess turbo boost is vented via the air cleaner box. As far as synthetic oils, the most common and best priced to my knowledge is Rotella 5W40. Available almost anywhere including Walmart at fairly good prices.

Thanks , i thought that was what the serv. manager was reading to me on the phone. is rotella synthetic a decent oil? never used synthetic before, we are getting -25 deg temps for the rest of the week, figured it would help a little.

I have heard nothing negative about it here or on other sites. I use it but it was 80 degrees here today. Man living in s. ca. is ruff.:-missingt

grrr Its so damn cold here

I doubt the dealer is using rotella though. I don't think motorcraft makes a synthetic but if they do thats what they are using.

Most Ford dealers probably use Motorcraft Super Duty 5W40 Synthetic although there are quite a few others which are acceptable/recommended and popular as follows:

Chevron Delo 400 Synthetic 5W-40
Mobil 1 Turbo Diesel Truck Oil 5W-40 Synthetic
Mobil Delvac 1 ESP 5W-40 Synthetic
Schaeffer's Supreme 9000 Synthetic 5W-40
Shell Rotella T 5W-40 Synthetic
Valvoline Premium Blue Extreme 5W-40 Synthetic

There are more brands than those listed above... although most 6.0 owners seem to report best results using 5W40 Synthetic especially when temps are below freezing. Good luck:-X22

Hemborg Ford in Norco told me that they use Valvoline.

Motorcraft synthetic here at our local dealership is $46 a gallon. I use Mobil-1 turbo diesel truck oil. It has the lowest pour point of any syn on the market.....thats important in the cold