Oil changes with synthetic

[pasusan]

How often do you change your oil if you use full synthetic oil?

We have a Chevy 6.0 gasoline engine. We are putting Mobil 1 synthetic oil into it and are finding differing requirements. Some say go by miles, others say if you don't put on that many miles change it every year.

We only drive it 2000 to 3000 miles per year. Can we really wait for 7000 miles or more to change it or should it be done every year?

My thinking is why go synthetic if you have to do it every year anyway?

[StirCrazy]

lots of opinions out here so Ill throw mine in, well not realy an opinion, but with my old truck a 1999 f250 7.3 diesel I put a bypass filter on it and did an oil analisis program to determin how long my oil would last. it lasted
80000km/50000 miles before its base depleted to a point where I should change it. I settled on a change interval of 50000km which is 35k ish miles to give me a buffer. saying that a oil doesnt wear out unless it is overheater is just untrue. yes that will acellerat it, but the base is what wears out usaly long before the other properties of an oil and the more humid it is and the more stop and go trafich and short interval run times the faster it will wear out as it is what nutralizes the acidity that is creadted by the gunk your oil keeps in suspension and moisture to keep it basic. if you do oil analisis and you base is low you can just add more base. old truckers used to do this all the time with out knowing it by adding gallon of oil to there rig every week to top up the leaks. in a normal vehicle I always recomend that you go by the owners manual as they cannot deny use warenty if you do that so they must figure it is a reasonable interval. if you modify your filtration system you can go longer but you have to pay for oil programs to determan how far then you should do one every now and then to determin if you have any issues going on. my self I go by the ford factory oil minder but I use the extream duity oil.

Steve

[ksss]

Amsoil had documented hundreds of thousands of miles logged on semis running their oil, changing nothing but the filters. Everyone can argue about how long oil should be changed, but without using real data from a lab, and not just algorithms, personal preference and superstition your just guessing. If you have the oil lab checked, you can know for sure.

[fj12ryder]

dodge guy wrote:

Groover wrote:
The bottom line is that oil will essentially last forever unless it gets contaminated or overheated. I sincerely doubt that he is overheating it. The main source of contamination is cold starts that allow more blowby of unburned fuel and exhaust gases which contain carbon and water. The problem is compounded if you don't get the engine hot enough to boil out the water. If the car sits in a garage without being driven the oil will last a very long time. Just watch the short trips and temperature cycling.

I have noticed that time spent on a dealer lot does not seem to count towards oil changes. At least that is what the dealer told me when I bought a truck that had been on the lot for 7 months.

Oil is contaminated on the first start. It also gets heated all the time. Doesn’t need to get overheated to fail. Even run at proper temp oil still breaks down!

I take it you have the documentation to back up that statement? Personally I think it's nonsense. I have mine checked at every oil change, and contaminants are always extremely low: fuel less than .5%, antifreeze and water 0, Insolubles .3%. Granted those are at 5,000 mile intervals.

[time2roll]

Groover wrote:
I have noticed that time spent on a dealer lot does not seem to count towards oil changes. At least that is what the dealer told me when I bought a truck that had been on the lot for 7 months.

I bet resetting the OLM is part of the new vehicle prep. That is a reset without changing the oil.

[dodge_guy]

Groover wrote:
The bottom line is that oil will essentially last forever unless it gets contaminated or overheated. I sincerely doubt that he is overheating it. The main source of contamination is cold starts that allow more blowby of unburned fuel and exhaust gases which contain carbon and water. The problem is compounded if you don't get the engine hot enough to boil out the water. If the car sits in a garage without being driven the oil will last a very long time. Just watch the short trips and temperature cycling.

I have noticed that time spent on a dealer lot does not seem to count towards oil changes. At least that is what the dealer told me when I bought a truck that had been on the lot for 7 months.

Oil is contaminated on the first start. It also gets heated all the time. Doesn’t need to get overheated to fail. Even run at proper temp oil still breaks down!

[Groover]

The bottom line is that oil will essentially last forever unless it gets contaminated or overheated. I sincerely doubt that he is overheating it. The main source of contamination is cold starts that allow more blowby of unburned fuel and exhaust gases which contain carbon and water. The problem is compounded if you don't get the engine hot enough to boil out the water. If the car sits in a garage without being driven the oil will last a very long time. Just watch the short trips and temperature cycling.

I have noticed that time spent on a dealer lot does not seem to count towards oil changes. At least that is what the dealer told me when I bought a truck that had been on the lot for 7 months.

[Cummins12V98]

JIMNLIN wrote:

Cummins12V98 wrote:

time2roll wrote:

Cummins12V98 wrote:
Never heard of 80% rule.

Ratings are always under the actual capabilities with a builtin margin.

1/2 ton = rating x 80%
3/4+ = rating / 80% 😉

So by me running at my SAE RAWR of 9,750# I am overloaded?

Maybe some documentation on this 80% rule.

Its a rv thing from the era when our trucks had wimpy 180-235 hp v-8 engines and inline 6 cylinder engines and 1 1/2"-1 3/4" wide front and rear brake shoes....hot running slusha' automatic tranny with no TC lockup...small radiators/etc Probably a good idea....back then.

Todays LDTs ??
We use them in commercial service up to 100 percent capacity and make it fine for 250k-300k +/- miles before major repairs pop up. Works for rv trailers also. These trucks sure aren't like 1970-80 versions.

Thanks!

[Cummins12V98]

dodge guy wrote:

Cummins12V98 wrote:

dodge guy wrote:
Here is another way of thinking about it!

Why is it when it comes to tow ratings most people say to never push the ratings and to only go 80%! Yet when it comes to maint most people want to push the interval to at or farther than what the manuf recommends.

Just curious!

Never heard of 80% rule.

Ratings are always under the actual capabilities with a builtin margin.

I know that, you know that, but there are many people that don’t understand that.

Guess so!

[FishOnOne]

Grit dog wrote:

Cummins12V98 wrote:
"No way could I go a full year without an oil change. I just couldn't do it."


The oil Companies love you.

His bank account probably still loves him too, since he's rolling a 250k+ mile (I think) truck. He's saved more money than many of us put together and the peace of mind of doing something that may keep a high mile engine ticking 1, 2 or 5 years longer is worth far more than an extra $50/year in oil.

The one thing that can kill a Chevy LS engine is the small passage on the hydraulic lifters can clog up and the lifter will no longer function. Keep your OCI reasonable and that Chevy engine will last a loooong time.

[JIMNLIN]

Cummins12V98 wrote:

time2roll wrote:

Cummins12V98 wrote:
Never heard of 80% rule.

Ratings are always under the actual capabilities with a builtin margin.

1/2 ton = rating x 80%
3/4+ = rating / 80% 😉

So by me running at my SAE RAWR of 9,750# I am overloaded?

Maybe some documentation on this 80% rule.

Its a rv thing from the era when our trucks had wimpy 180-235 hp v-8 engines and inline 6 cylinder engines and 1 1/2"-1 3/4" wide front and rear brake shoes....hot running slusha' automatic tranny with no TC lockup...small radiators/etc Probably a good idea....back then.

Todays LDTs ??
We use them in commercial service up to 100 percent capacity and make it fine for 250k-300k +/- miles before major repairs pop up. Works for rv trailers also. These trucks sure aren't like 1970-80 versions.

[ktmrfs]

dodge guy wrote:

ktmrfs wrote:

jerem0621 wrote:

mosseater wrote:
Many years ago, when Hector was still a pup, and folks still believed in silly things like objectivity, Consumer Reports did a pretty thorough test with NY city taxi cabs and oil changes. Sythetic was still a niche market then, but after running taxis for 100K miles on almost all readily available oil brands, they tore them down to inspect and measure. The conclusion was, as long as the oil was changed at the then-standard 3000 miles, it didn't matter if it was mobile one or PepBoys reclaimed oil. Their conclusion was to make sure you changed it. Take that info for what you paid for it.
That said, two things to keep in mind: Your truck may have an "extreme duty" PM schedule because you tow or haul (Ford dealer service manager told me even if you tow occasionally). Point two...I have zero doubt oil now is better than its ever been, so I have confidence that it's lubrication capabilities are up to the 5 or 10K mile task. But....that black stuff in oil, that makes it black? That's dirt. It aint food coloring. Contaminants are so named because they aren't supposed to be there. I have historically changed mine in my former sig pic F 150 because I ran the dog pee out of it when towing. It never went past 4000 miles without a change. For the cost of Motorcraft synthetic blend and a new filter, I'll eat the minimal cost difference to keep sleeping soundly at night with the new truck as well. When my odometer in my 7.3 gas engine in my new F-250 hits about 4000 miles, I'll be crawling under it again with my drain pan. Thats my 4 cents. Y'all can do as you wish. The cost of one oil change per year wouldn't make most of us even blink. I'd love to be in that club.

I Will be doing he exact same with my brand new 2022 Chevy. It's a turbo truck and I will be changing he oil at 4,000 mile intervals or when the OLM hit's 50%, whichever is first.

Oil is cheap, engine work is NOT.

Thanks!

Jeremiah

I've run one duramax 250K miles following the oil life indicator and still only uses 1/2 qt in 10K miles, and I've run 4 other vehicles over the 200K mile mark following mfg recomended oil and change schedule and again, non more than 1/2 qt between changes and Blackstone lab reports always has come back with high TBN and excellent condition on the oil. Change every 4K if you want but all your doing is paying extra $ to the oil companies.

We’re these all diesels? They have always gone longer on oil changes!

nope, the 2001 silverado is the only diesel in the group. the others were a variety of GM, Honda and mercedes. Actually 5 others now that I remember correctly, 3 gm's a honda and a mercedes. Now the mercedes does have a 9 qt sump instead of 5. Changed oil at recomended intervals, most were around the 7500miles or 1 year. Only the silverado had an oil life indicator

[dodge_guy]

Cummins12V98 wrote:

dodge guy wrote:
Here is another way of thinking about it!

Why is it when it comes to tow ratings most people say to never push the ratings and to only go 80%! Yet when it comes to maint most people want to push the interval to at or farther than what the manuf recommends.

Just curious!

Never heard of 80% rule.

Ratings are always under the actual capabilities with a builtin margin.

I know that, you know that, but there are many people that don’t understand that.

[dodge_guy]

fj12ryder wrote:

dodge guy wrote:
Here is another way of thinking about it!

Why is it when it comes to tow ratings most people say to never push the ratings and to only go 80%! Yet when it comes to maint most people want to push the interval to at or farther than what the manuf recommends.

Just curious!

Because they're two entirely different things?

How, they are both set by the manuf and engineers! Why listen to one and not the other!

[fj12ryder]

dodge guy wrote:
Here is another way of thinking about it!

Why is it when it comes to tow ratings most people say to never push the ratings and to only go 80%! Yet when it comes to maint most people want to push the interval to at or farther than what the manuf recommends.

Just curious!

Because they're two entirely different things?