I just bought a 91 F250 5.8. The mileage was stated as 87K, now being told it is more likely 187K if not 287K. Appreciate any recommendation for motor oil, also any additives if recommended.

 

I use castrol gtx high mileage 10w-30 on my truck. No complaints

 

Expect 100+ recommendations. Factory spec. is 10W 30. Go from there. Much easier to type oil into the search function on this site. Everybody has an opinion and story to tell.

 

Exactly haha

 

yup ... in addition you will get people who swear by all sorts of snake oil additives.

 

Sorry to come across as a d**k but this is a frequent topic on this and hundreds of other forums. Simple answer is Motorcraft 10W 30. Can't go wrong for the price. Same for the filter. Stay away from the orange can of death, aka Fram.

 

There is nothing wrong with Fram when used properly ... As targets!

They are easy to see a long ways off ...

-Enjoy
fh : )_~

 

I've heard some horror stories about Fram. But we've never had a problem with them. And my dad used them in his 89 F150 for the 22 years that he owned it.

 

I run Schaeffer's oils and Purolator filter. I run Schaeffer's in my semi, pickups, car, everything but my bike, and I could probably use it there as well, but use Rotella T6 instead.

My personal recommendation to everyone is as follows:

Run synthetic oils. There is no downside to them. There isn't a spec or application where they can't outperform conventional oils in your vehicle. Run an oils with a warm viscosity rating that suits your engine, and the lowest possible cold viscosity. (5w30 or 0w40 for example). Buy a brand you trust, can find easily, and want to pay for. There is NO bad brand name full-synthetic oil that I am aware of.

Use a high quality filter with a synthetic anti-drainback valve and robust filter media. Many brands sell such a filter, and many are made by the same factory so brand matters much less that construction.

Now, to make most of you squirm, I also recommend LONG intervals for oil changes. Nothing under 5k should be necessary. 7.5k is probably fine too. Beyond that, I'd sample on older engines and see what the oil can tell me. Generally, a healthy engine can go longer.

Don't think you can do these same things with a poorly running engine. Excessive blow-by will quickly contaminate ANY oil and make it perform poorly. Same is true for water/coolant contamination.

Don't pour additives in your oil. If they really added anything, the same stuff would already be in there. If OEMs could reduce warranty claims or bolster their reputation by specifying that oils used in their engines contain a specific compound, they already would. One virgin oil analysis claimed a popular additive contained nothing but 50wt base oil. No anti-foam agents, detergents, nothing. It cost considerably more that a quart of oil and had far less costly ingredients. This is not true of high-zinc additives that are recommended to support flat-tappet cams. Follow your cam manufacturer's recommendations in this case.

Green, blue, red or purple, conventional oil is conventional oil and synthetic oil is synthetic oil. Just regularly changing your oil will always be more important that what brand, variety or even weight of oil you use. Oil samples can tell you what 1000 forum posts never could, how your engine is wearing with your chosen oil. If you want to know more, pull samples. You may find you need a better oil, or that you don't need to change until 15k miles. Either way, the oil can tell the story.

 

Thank you all for your responses, insight and knowledge. So happy I found this FTE!!!

 

Print this out and frame bro, you said it 1000 times better than anyone ever could have.

 

Still needs some spelling and grammar work, but thanks.

 

This. It really doesn't matter what kind, but at some point past the recommended intervals any crankcase oil becomes loaded up with sludge beyond its ability to keep in suspension, combustion byproducts, acids and contaminates, additive package depleted, filter completely clogged and bypassed etc.

 

I run whatever oil is cheapest, because for the most part I found it doesn't matter at all.

 

With regular changes this is pretty much spot on. With non-exotic engine designs, most conventional oils will do the job perfectly well. I personally run, and recommend, synthetic oils for the benefits in cold starting afforded by the lower pour point and wider viscosity range that only synthetic oils can offer. Since most vehicles spend more time running at temp than below it, most wear occurs at operating temp where synthetic oils don't beat conventional oils by as wide a margin. Reach above average temps and synthetic oils pull away again quickly.

If you do a lot oftrips under 5 mins, live in exceptionally hot or cold climates, tow or haul heavy loads regularly, or regularly enter into competition, synthetic oil becomes a must-have in my opinion.