jprevat

iTrader: (1)

I would have to disagree. On these older trucks the detergents in the syn oils can actually clean too much and lead to problems later on.

02sport4

Regular dino oil breaks down to fast. Ford specs out 5-20 full synthetic oil so thats what I use

jprevat

iTrader: (1)

In our trucks the motorcraft 5w-20 is a syn blend and looks like this.




If is has used dino oil and are high mileage you will have deposits in your engine or sludge. My thoughts are that the detergent breaks these deposits down and as a result you may have oiling problems but thats just my logic.

Red-Ford

Doesn't the type of oil you use depend on a multitude of factors, such as the climate, mileage of vehicle, etc.?

To the original question, oil could be a factor, but the only other issue I have had experience with is the fan clutch. I would check the fan clutch to see if it is still good, that might be your problem. It sounds like the knocking is very quiet, and that's what it was for me.

jprevat

iTrader: (1)

Its not quite as variable as you would think. In our engines anything above a 5w-30 is not recommended as far as I know.

Red-Ford

Hmm... Jiffy Lube told me to use 10-40 for my truck, so that's what I've been using =\.

jprevat

iTrader: (1)

10-40 worked just fine in the old 9th gen and earlier pushrod engines but I wouldnt use it in a mod motor. Maybe I would use that in Florida in tge summer... maybe.

me1234

I just stick to the manufacturers recomendation. I know in alot of newer vehicles and imports it can be kind of a chore to pick the correct oil bc they have like 5 recommendations depending on the temp