Seen -4 with 15-40 rotella with no issues in my service truck and only run that in my pickup also. There is a lightweight oil that is used by the powerstrokes but not sure how good it works on a gm or cummins.


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Im going to try using 5w40 in the 4bt this winter too. I don't think Id want to use non-synthetic even if I could find it

Jake

 

I've seen the difference 5W made to 15W (both rotella) in a 7.3 turd in cranking speed and ease of cold starting.

I know the 15W will work, but those 10* mornings last winter when I had to fire her up cold with no heater were rough.

The point of no synthetic is regular 15-40 isnt synthetic. Switching to synthetic with a 340K mile engine and it WILL burn oil, just a question of how much.

Looks like I might just give it a whirl and see what happens.

 

Switched to 5-40 around 175,000 miles on my 6 cylinder and it never burned a drop and it was using a slight bit of oil up to that point. It currently has over 300k.
hemichallenger , do you have any credible proof that an older engine will burn oil when switched over to synthetic? I've never seen one burn oil from being switched over but i haven't seen many hi mileage engines switched over.

 

Might have more to do with the lower viscosity oil passing the rings unlike the the thicker 15w and not necessarily whether or not its synthetic

I've also read that most 5-10-15 oils have nearly identical viscosity once at operating temp

 

Any gas engine I've switched to synthetic (most around 100-130K) started burning oil. One vehicle in particular I owned had nothing but 10min. oil changes its whole life, in 3K miles it used 3 qts. Switched back to regular non-synthetic and little to 0 consumption. Tried it in my 360 powered ram, parents 5.4 f-150 and my buddy tried it in has 4.2 v-6 f-150. All burned oil, never did before and havent since switching back.

<-- not a synthetic oil fan for anything.

I think the problem is synthetic is to slick for my applications causing consumption that never existed before, regardless of viscosity. Hence, if they made a 5-40 regular oil I wouldnt have even posted this thread. Just looking for any insight from someone whos done it, because I havent tried it with a diesel, past experiences were not good with gas engines.

 

You know its funny that you would want to stick with the crude oils....synthetic is made,and is cleaner that taking the old crude and refining it to a certain level of clean....I have used both types,and prefer the full synthetics.I have lots of miles of three different 6bt's,and one GM6.5...and the 3.9....and the synthetics seem to have less wear,and get O P much faster than the 15-40 stuff....and,if you think the oil is "too thin" then think about atuomatic transmission oils....I also use the 5-40 synthetics in several air cooled commercial mowers that I run....and they have less wear....

 

Yes, gas engines with hi mileage are definitely going to react differently than a diesel. On a 12v cummins I would not be afraid to switch it over even at hi mileage. But if non synthetic is working fine then I wouldn't bother.

 

But if non synthetic is working fine then I wouldn't bother.

Did you read the OP?

I learned something interesting:
Rotella 5w-40 is JASO certified for motorcycles and wet clutches. Score! (I have a bike and 4 wheeler). Apparently A LOT of bike guys swear by it too.

 

Yeah, I read it and it's been a long day. I forgot for a second what he was asking. The biggest benefit of synthetic oil is reduced friction. Which means it will crank faster in cold weather and tend to get better economy. As far as it using oil, that will depend on how it was taken care of. If you decide to switch to synthetic oil , on the first oil change I would highly recommend only going about 2-3k and then change oil. The synthetic oil will tend to clean out the build up of carbon sludge and will plug the filter and dirty the oil. Also, all 5-40 oils are full synthetic.

 

Well ironically I read an article in my dad's monthly Handyman magazine and they talked about people using lower viscosity oil for cold starts. 5w-40 oil for winter would be a lot easier on the engine than the 15w-40 for spring and summer. MotorCraft (Ford's brand) is all Synthetic blend and works nicely. AmsOil is a good brand but you'll pay out the rear for it at about $7 or $8 a quart.

 

tried the 5-40 on my old landcruiser...got some cheap rotella-T6 synthetic on sale somewhere (wallmart i think).didn't notice much consumption difference (burns a liter every 1000k anyway),but i tend to swap between grades on a winter/summer basis,need or cost dependent.iv'e even run 20-50 in hot summer months.

definitly a huge difference in cranking,even over my prefered 15-40 synth' oil.winters here are sometimes crazy...-50f is not uncommon.

 

I run Valvoline 5w-40 during the winter in all my Cummins motors, my 4BT (when I still drove it in the winter), my 6.7 and my 98 12 valve.

 

Id say try it. its 15 minutes to change it back out if it doesent perform like you want.

 

I've never had any problems switching to synth on high mileage gas motors. Haven't tried on the deezils yet.



Easy to say when it's not your money being wasted.

 

It seems reasonable cost wise, not an expensive experement, the oil has to be changed sometime...

But opinions are like a**holes, everyones got one and they all stink....my two cents. your mileage may vary

 

That's what I'm going with next oil change. Many believe you should go with 5w or even 0w at all times. It's closer to optimal viscosity at cold start. Once at operating temperatures, the friction modifiers maintain a certain viscosity.


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I have a question? I heard that its easy to change from synthetic oil back to regular, ok. but would you want to clean your engine especially if you have a 7.3.
it seem to have a resovoir which holds a couple of quarts and mixing the oils would it cause a failure.??

 

no and no...having owned a 7.3 (which i still miss dearly),i switched back and forth with no ill effects whatsoever.the resivoir is the h-pop tank,which can be drained,or rather,sucked out with a fluid evacuator.it is smart to do that,as the res' often fails to drain,thus leaving your very expensive unit injectors to live on dirty oil.

 

Thanks guys.

 

Probably the best thing I've heard for longevity is running a bypass filtration kit and it run down to 2 micron or smaller if possible. However no one on here has ran one of those. Supposedly you can go 20,000+ miles between oil changes. Filtering all the crap out of oil will extend to oils life and helps lubricate your engine.

Here's a couple videos I've found over the past couple years.

(CTD with AmsOil bypass) http://www.youtube.com/watch?v=oAGo6jbDLOQ

(From PowerStroke help, its a 3 parter):

1. http://www.youtube.com/watch?v=onqGyKy69qQ
2. http://www.youtube.com/watch?v=k7Dm4Xkv8ws
3. http://www.youtube.com/watch?v=0ScGiBgVSNM