Oh and FWIW, I'm running the High Mileage 15/40 M1 oil.

 

A good oil-related website that might help clear up some of the comments in this thread: www.bobistheoilguy.com . There is no need for any additive, supplement or otherwise in motor oil, synthetic or conventional. Synthetic protects to higher temperatures than conventional because it doesn't break down with heat, and protects better at cold temperatures because it still flows freely when conventional oil is a big blob of goo.

 

What about Additives?
Well, it's the old "good news/ bad new" deal! He supports my "extra protection at cold start", however after that things go south when a questionable amount if moisture in relation to real life conditions is added to the mix. Also the test is specific to the Lucas oil stabilizer, not the Lucas "Synthetic" oil Stabilizer I use & recommend. I've never used anything but the Synthetic oil version, but use it supplementary in everything from my Harley to lawnmower, all vehicles, Commercial machinery of all types,makes and models, including compressors from 5 hp to industrial 24/7 continuous duty units.

 

Motor oil doesn't need any kind of climbing property since there is a pump to circulate the oil to the top end. You may be doing more harm at operating temperature if the oil is aerating than you are helping at cold startup.

 

I'm gonna stick with a MotorCraft FL-1A filter, and Motorcraft 10W-30 synthetic blend oil.

I change it whenever the hell I feel like it basically haha.

 

Is there such a thing as mobil 1 10w 30 Diesel oil?

i've been running the 5w40 mobile one now for a year on my 06 6.0. saw a slight increase in mileage but according to the manual it should be 10w30.

does it matter if the jug actually says, diesel motor oil?

 

dapgar, technically you should see a DECREASE in mileage not INCREASE.

Honestly I don't even think we as humans can notice it but here's why I say that.

5W40 oil is LIGHTER than 10W30 Oil at STARTUP/WARMUP, but HEAVIER at OPERATING TEMP.

When the oil is lighter, the engine has to work less to turn it, but it also will not lubricate as well. When the oil is heavier, it's harder to turn/churn but it lubricates better.

So if we can actually notice changes by messing with oil weights, you should notice the truck starting faster, but also a decrease in gas mileage.

I don't think it being a synthetic will flip that, but maybe it does. Who knows I just make sure oil in my truck haha. Like I said I can't but buying Motorcraft products. So I do that.

 

I run conventional oil in mine and always have. It has 280k on the clock and still runs as good as ever. I change it every 3k miles and always use an FL1A Motorcraft filter.

I do not buy the claims that you can go 10k miles on synthetic. I know some people do stuff like that. However, no matter what oil is used, dirt and moisture etc will still find its way into the crank case.

I'm not saying that synthetics are bad, I just don't think its necessary at all on our trucks. Now with a modified motor, that might be different.

I run a sythetic blend in our 97 Cobra, and 65 Stang.

 

I don't know if running an upgraded Ignition system at 16 BTDC would be considered "modified", but I wouldn't leave home w/o a multigrade Synth in the engine. I do round trip runs up to Oregon 3-4 times a year, where I average 80 MPH & go through both tanks between stops. A rather heavy motorcycle strapped to the bed & A/C blaring. I think it deserves Synth.!

 

well like i said before I've been running 10K oil changes on my lil 4 banger commuter car for a long time now with no ill effects. I still change the filter every 5k just to make sure the contaminents are filtered out of the oil properly... I am think since the oil I am using is rated for 15k I might up the antie and go for 12k oil changes with 4k filter changes...

even if I was running a synthetic blend I wouldn't change my oil till 5k... 3k oil changes are a waste of money and time unless you only drive 6k a year and change your oil every 6 months instead of by milage. You have to think about it this though... big rigs (18 wheelers) have been running 10-20K miles before oil changes easy for the last how many years???? The special additives and formulas that used to be used in the big diesel engine oils are now available and already added in conventional and synthetic oils that you buy over the counter at the parts store... We are thus buying better oil now than in previous decades so as long as you don't buy a bad/cheap oil filter (ie fram...) you'll be fine to run any engine to 5k on conventional alone...

 

I'm at 7-8 K miles, w/ an extended range filter & the oil "looks" great! I think I'll follow your lead & change filter only, keeping the oil for a few more K's. Maybe send a sample in for testing after the filter change. I have great compression for an 23 year old 302 engine (178-184 psi). I'd like to keep it that way, as long as possible!

 

I ran across a link that dissected/ tested filters. You're right about Frams, but there are lots worse! Name brands too! I'll see if I can find to link again.

 

my synthetic oil after 10K miles and 2 wix filters still looks better than my buddies oil (350 chevy with walmart oil and fram filter) when he changes at 3k... I have been trying to change his ways but it's hard to get a stubborn 56 year old to change his ways especially when it's a young buck trying to convince him...

 

I run wix and wix alone! I have been tempted to try the other brands that are cheaper and come in those package deals (5qts of oil and filter for $20-$25) but always stop myself knowing the oil and filter are inferior in design and quality. I have been wanting to try Royal Purples Synthetic oil filter but no part stores in des moines carry them at all... Royal purple needs to get a parts store that carrys their full line here in des moines!!!! But then again Royal Purple is extreamly proud of their stuff... upwards of $6-8/qt on oil...

 

Though I'd take the "Royal Purple" plunge too, on the next change, but multigrade Mobile 1 Synth. has been very good to me! .................................................. ...........(W/ a 1qt. Lucas Synth. Stabilizer supplement, which doesn't have a large cheering section around here!)