So it seems that I got a little too excited about the sale price of Valvoline Heavy Duty Diesel 15-40 at my local NAPA a few months ago and picked up 4 gallons. I did my last oil change (about 5k miles ago) with the stuff and today as I'm buying new oil for my next oil change I notice something: I did not use synthetic oil last time!! Bought the truck a couple years ago & PO had been using Mobil 1 synthetic. I switched to Valvoline diesel synthetic and had been using that. Then I screwed up on that last oil change and used regular Valvoline Heavy Duty Diesel. Meanwhile the truck has been running great. It cold started all winter in Alaska and I barely was plugging it in- only when temps got below 20. HOWEVER, it has developed a thing where it burns 1 qt. of oil for every 20 gals of fuel I run thru it. I cant remember if I noticed this problem before I switched from synthetic. Could there be a causal relationship there? Did I do damage to my engine from making the switch, and most importantly how should I proceed from here?
THANK YOU!

 

Didnt, for all the engine cares you can change from Syn to dino every change (and vice versa) heck in all honesty you can do the change with syn then top off as needed with dyno but that negates the bonuses from using syn.

 

many of us have heard people say that once you go syn, you never go back. but i've never heard a valid reason for this strongly held claim. i've worked on vehicles that had been back and forth, and never seen any oil-related problem in them.

i have heard that to run a blend of 20% synthetic will give you 80% of the benefits of running full syn, while costing less than full syn.

we also know that some oils on the market are a synthetic blend, and if they're on the market, it must not be destructive.

the only problem with switching TO syn is that it'll sometimes find a new place to leak which it hadn't found before.

 

no problems at all. all my truck has ever had in it except for what it came from the factory with is velvoline all fleet 15-40, napa all fleet , napa premium 15-40, and valvoline premium blue15-40, and valvoline heavy duty diesel 15 -40 are all the same oil with different names.
my 88 now has over 496,000 miles on it with that oil in it and no problems at all.
the only benefit i see to using synthetic oil is that it costs more and as Josh said it finds places on your engine to leak out of..

 

On an old engine there are few benefits to using synthetic but on a new engine it can prevent wear big time. In fact an old school BMW mechanic told me to break an engine in on conventional oil but switch to syn later because syn oil can prevent rings from seating and grooving the cylinder walls properly and they won't do their job as good. Who knows if its true but something to think about. He also said that this pertains to old iron engines and not so much newer aluminum ones. But like I said who knows?

 

As stated above. The oil burn dosen't seem bad to me for that old of a truck. You will notice less oil burn with synthetic oil in my exsperiance.

 

The po of my truck used synthetic. i said eff that and run non-syth. still have really good oil pressure. does not seem to be causing any issues.

 

my 99 crown vic is exactly opposite to what you claim. had fresh synthetic in it when i bought it. used 2 quarts of synthetic oil in 5,000 miles. switched to valvoline all fleet 15-40 at 21,000 miles and have not had any oil loss since changing. still do the 5,000 mile change interval, and now have 82,000 miles on it.

 

I'm not sure on the gas motor for oil burn, but in my SD F350 It used less. In fact none at all has to be added in 7500 oil changes. I guess different motors act different. If he wants to run diesel 15-40 the by all means run it. Whats a quart of oil between oil changes, or did you say 1k? My 6.9 van uses about that much and it runs just fine. I wouldn't worry, your fine is the point.

 

If your oil consumption has suddenly increased, it might not have anything to do with switching from syn back to dino -- you might have a clogged CDR valve. Might want to take it off and soak it in some solvent for a few hours.

 

LOL! the things people say.

Truth be told that synthetic oil was developed by Hitler funding.
He had tanks in Staligrad that wouldn't start up in the Russian Winters.
So they developed Chemicals from petrolium to come up with a man made lubricant able to flow at sub zero temperatures.

They had also developed the first combat jet fighter wich also used Synthetic oil.

Ask your older family members how many American GIs died Bombing German Synthetic oil factories?

Synthetic will always be superior to conventional when the user actually uses it.

No Jet engine ever flew with Conventional oil in the oil sump.
Why? Cause it wont FLY! Conventional oil burns up past 275F

Synthetic hangs out all day @ 500F without any breakdown.

I dont waste my time and money with pie in the sky oil sales

I buy the best and let the cards fall on the table...


Javier

 

as stated,you can run full synthetic,a semi,a few full and a few dino's and swap back and forth all you want.that wont hurt it.the more full you use,the less engine ware you'll have.
my experience with full synthetic is that it's burning about the same,perhaps a tad less,but the big difference is seen in the color of the oil.with dino originally,she'd turn black as coal inside just a few days.with the full synthetic she actually holds a little gold color for a long while.


what are you running for amsoil Javier?
i just switched from mobil 1 5w 40 turbo diesel to amsoil Series 3000 SAE 5W-30
i can feel the difference.probably because i also switched back to lighter gear lube at the same time,also amsoil.together these freed her up a touch.easily felt going down the road.time to track economy again now that summer blend is back and no more plowing.

 

i would walk before i ever put any spamsoil product in my vehicle.

 

i didn't see anything else for diesel synthetic 30 weight.
what don't you like about amsoil Tom?
the only thing i don't like is that i had to order it.since it's not changed often i suppose it's not too bad.i just made sure to buy 4 extra quarts to have on hand to get me through a 10k mile interval.mine drinks the normal 1 quart every 3k miles.has since i bought her with 49k miles,so i should be good.

 

their sales technique, and the fact they will not submit their oils for rating. their trust what we tell you about it, we know what we sell is good just don't cut it for me.

also, when i have a "salesman" telling me that their oil is the best thing since buttered bread and if i don't use it my engine will not last. well, i only use valvoline all fleet 15-40 in my vehicles. this same amsoil salesman has never gotten more than 5 years and 100,000 miles out of a vehicle before blowing them up.
my 88 now has over 496,000 miles on it and is still in excellent condition.