So a month ago I got a 2000 F250 6.8L for my wife. It needed a oil change bad, & I changed it with Mobil 1 5W -30 High Mileage & a Mobil 1 Filter. Its already dirty & maybe burning a little. Thinking even though it's high mileage oil full synthetic maybe to thin for this truck with 150,000 + miles. Any suggestions? Thinking of using Mortorcraft Syntheic Blend 5W 20 next time with Motorcraft oil filter. Anyone know how long the filters would be good for on a truck this age? My 2013 6.2 obviously goes 7500K on Mortorcraft Syntheic Blend, but think with this combo still changing every 3K on the 2000.

 

I think you can use 5w30 or 5w20....I believe that there it a TSB saying to use 5w20 for that year. I wouldn't use anything thicker than the 5w30 in a modular engine. Also I would always use Motorcraft oil filters "FL-820S"
Motorcraft make good Synthetic Blend oils.
Also I wouldn't wait for 7500 miles to change any oil even if its Full Synthetic.
....Gage

 

I use Motorcraft filter's and 5w20 oil. Easily purchased from the local walmart. I started at 3k intervals but now will be changing around 4k. I make a lot of short drives is my reasoning for this. Check out the Excusrion tech folder there is a video on oil filter comparison and a good reason to use quality such as your Mobil 1 or Motorcraft.

 

Thanks guys. Just picked up 5W-20 Motorcraft & Motorcraft filter. Thinking of changing the oil tomorrow which is WAY early for Mobil 1, but worried being full synthetic it's to thin for this engine at 150,000 + miles. Not to mention it's already a little black. Thinking the last oil from before I bought it was WAY over due for a change, so the new oil might have picked up the extra grime from the last oil. Thoughts? This Mobil 1 has less than 1k on it, but better safe then sorry.

 

Ok just changed the oil to Motorcraft, I checked out how much oil I got back of the Mobil 1 High Mileage. In 18 Days & 525 miles I got back 6QTs (Usual Fill Amount.) out of a the 10QTs I put in over those 18 days. So I lost 4QTS in 525 miles I also found that there were only 4Qts of oil from before my ownership. I HOPE the Motorcraft Synthetic BLEND works out better for this old engine then the Mobil 1 High Mileage. There is no oil leak, and I haven't noticed any thickening of the exhaust smoke indicating oil burning either..... I'll keep you posted on how the Motorcraft does, but would love ANY advice or input on this....

 

I think your right that the engine was probably way overdue for an oil change. Synthetic oil is very good at cleaning the inside of the engine and probably was picking up years of neglect in the short time it was in there.

As for the synthetic oil being to "thin" for the engine, the 5w20 you just put in is thinner than the 5w30 you took out. And if it's not leaking, and you don't have oil in your coolant, then the only other possibility is that you're burning it.

 

Yeah I know 20W is thinner than 30W, but heard full synthetic is thinner than Dino too.... I'm grasping at straws I guess. There is no coolant in the oil. I will have to check the coolant overflow to see if there is oil in it. Losing a quart ever 100mi is a lot though... May have to start shopping for a rebuilt motor huh?

 

Maybe a bad oil cooler?.....

 

Checked the coolant. Looks good. More like Mountain Dew than Root Beer... If it was burning that much oil shouldn't it show in the exhaust?

 

I would have to say the exhaust may or may not show the signs of oil burning. I would start by changing your pcv valve and see if that makes a difference.

 

Did two weeks ago because of the broken throttle adapter. I appreciate the advise though. Anything else that maybe a easy fix?

 

Maybe I should pull some spark plugs & see if they are fouled....

 

I am currently experimenting with my V10 oil loss. For the last 9 months it seems I lose 3-5 quarts between oil changes. No smoke, no leaks, not in coolant.
I have been using Motorcraft 5-20 synthetic blend.

Last oil change I got full syn Mobil 1 5w20. I'll keep you posted.

 

Sounds good. I'll keep updating too. Your truck still have have horsepower?

 

I would recommend straight dino oil, no synthetic and change it every 3k. The only reason to spend big bucks on synthetic is to run it more miles between changes. Why?? I like Chevron Delo or Delvac and go one click up from the recommend since Ford recommends synthetic or synthetic blend. If you really want to get into oils for engines, go to www.bobistheoilguy.com , and you will get the dose. Also for older engines that you do not know the oil change history, the only product is www.auto-rx.com , and believe me, it works.