Synthetic Oil

[Anonymous-0]

I've read a lot of discussions on here concernin' Synthetic Oil. My 1998GMC Z71 has 109012 actual miles.Changein' oil at 3000 miles, it doesn't use any. On the advice of a couple of mechanic friends, I'm changein' to Mobile 1, 10w30 Synthetic. Question is....do I still change every 3000 miles or can You go longer between changes without engine damage...If so, at what mileage do You change? If You can go longer betwen changes, do You just change the filter?
Thanks,
Bill Caldwell

 

[Clarkbug]

Hi Bill.

You will probably get as many different answers as you do replies, but Ill throw my hat into the ring.

With synthetic oil, you definitely can extend your drain intervals. I know some folks that change synthetic at the same time as conventional, but I think thats a huge waste of money. You can extend your intervals at least twice as long, some folks go much longer (up to 15000). I recently made the switch myself from conventional to synthetic in my car, and all I did was move my change interval from 3000 to 5000. On my car, the suggested interval is 5000 for conventional oil anyway, but I figure an oil change is cheap insurance.

I have also heard of some fellows just changing out their filter at 3000 or 5000, and then topping back up with whatever they lost from the filter.

Just be aware that with that many miles on your engine, you may end up with a few oil leaks as your seals and gaskets get used to the synthetic. I have heard that the synthetic oil can clean some of the gunk that seals up small holes and then you get some weeping. I havent experienced it myself, but I wanted to pass it along, I hope its not just a rumor.

 

[Anonymous-0]

If you don't extend change intervals then whats the point? sounds like your having good luck now so if it ain't broke don"t fix it.

 

[RobMD]

synthetic oil = joke.

Any time some maker brings out a different type of oil, the people act like it's a miracle: "oh my Gawd, Now I can drive my truck harder" or "oh my Gawd, I don't have to change the oil as often".

...You get the idea.

If you change your oil properly at 3000 mile intervals, and use a reputable oil and a good filter, you'll be in business for many more miles.

If there is ever a time where your vehicle is starting to use a quart of oil in a relatively few amount of miles (maybe around 1500, 2000 miles), then you can start using the next heaviest oil.

Simple.

 

[Anonymous-0]

Have used Mobil 1 since the mid 70's, when the advertised 25,000 mile changes on the can. I was used to changing conventional oil at 3000 miles and did not trust running oil that long. I had it anylized at 3-6 9-12,000 miles and the report said it was good for much more. I decided that once per year oil / filter change was about right for me and have done that ever since. Last month I replaced lifter cover gaskets on my 80 gmc 292 with 270,000 short trip farm dirt miles on it. Inside of the engine is very clean,not even the bit of varnish on the lifters that makes removing them difficult.
I would not worry about synthetic oil causing seal or gasket leaks,mine don't leak. There is nothing about synthetic oil that will "clean" an engine. It is the additive package that keeps an engine clean,and the additives in Mobil 1 are very much like those in premium mineral oil.

Here is some correct info about synthetic oil from the makers of Mobil 1.
Mobil 1 FAQ.

 

[Bob]

Belgian,

You posted "If you don't extend change intervals then whats the point?"

There's a BIG point, if you live in a climate with CCCCOLD winters, as some of us do.

The synthetic makes for MUCH easier cranking on cold starts, and supposedly does a much better job of preventing wear at startup.

I run synthetic in the winter, and keep the oil change intervals within factory guidelines.

Just 'cause the oil is synthetic, and doesn't "wear out" as quickly as dino oil, what's to prevent tiny abrasive particles from accumulating, as well as moisture and combustion by-products from the cold weather operation?

Even GOOD oil is a cheap component of the cost of operating a vehicle, and I can't see ANY reason NOT to change even synthetic oil at a reasonable interval!

 

[RobMD]

By the way, this is an OPINIONATED STATEMENT.

 

[2t2@IA]

I agree with what you say. I have a 2004 Chrysler Pacifica with 40,000 miles. I switched to Mobil 1 about 5,000 miles ago. I always was skeptical of claims about milage improvement with different oils. However, I get about 1.5 miles per gallon better milage with the Mobil 1. I would not have believed it.

 

[HENRY E NC]

I have used Syntec since it has been on the market and have run all my engines at least 150,000 one going on 200,000 and use it in my tractors. I change oil every 7-8000 miles and change filters at the same time. Mostly I have used 20W-40 but when I was towing a 10,000 lb load I used 5-W 50. I have never had an engine problem ever using synthetic oil. I also use synthetic transmission oil. There is definitly an increase in lubricity and it doesnt break down or form harmful acids. Amsol sell a lifetime oil, a 65000 mile oil and several others for mucho dollars But I think that Mobil pone and syntec have to be as good as there is.

 

[sammy the RED]

Idrive p/t for a guy that changes his oil in the truck once a year.
The truck has 490,000 miles on it and still running strong ! 8)

 

[RodinNS]

Nuttin' stirs the pot like an oil question....
For what it's worth, some of us here run plain old walmart dinosaur oil on some rather extended change intervals without ill effect. Engines and lubricants today are a lot better than what they were 40 years ago yet th change intervals are still the same? Dunno if that makes sense really, especially to me where 95% of the driving I do is highway.
I do know that VW uses synthetic oil and the change interval is quite a bit extended. I'm thinking 32000 km ~20000 miles? That's on the TDI's. They seem to run fairly reliably for about a half million miles or more.

Personally, I'm from the school of thought that if you're going to use syn oil, you're going to double the change interval to pay for it, or why bother...

Rod

 

[ldj]

Hummmmm?? I don't understand. I change my oil to get the dirt out of my engine. I'll never believe using synthetic will keep dirt out of my engine. The dirt that gets in my engine gets there because the air filter can't catch everything and from combustion of gasoline. It stays there because the oil filter can only catch some of it. To get the dirt out I have to drain the oil and put on a new filter. I'm not saying synthetic oil isn't good, I'm saying it won't keep dirt from getting in your engine. If I used synthetic oil, I would still change at 3000 mile to get rid of the dirt. I don't want that dirt to stay in my engine for 10000, 25000 miles or what ever they say. At 25000 miles I've already changed my oil 8 times. Look how much dirt I've removed that didn't keep circulate through my engine.
Maybe I'm wrong, but it makes me feel good.
L.D.

 

[Anonymous-0]

I agree that without a good air filter, all is lost.
My experience with synthetic oil over the last 30+ years tells me that synthetic oil under the exact same conditions as mineral oil does not get dirty nearly as quickly.
The oil film that forms the seal between piston rings and the cylinder wall is so much better with synthetic oil that an engine that uses a bit of mineral oil will use 1/2 or less of synthetic oil. I believe this much better oil seal between the rings and cylinder wall prevents a lot more of combustion products and dirt from getting past the rings and into the oil. Synthetic oil will take atleast twice as many miles to appear dark and dirty, also it does not develope that nasty cumbustion products odor nearly as fast as mineral oil.
My experience has led me to believe that synthetic oil does not get nasty nearly as fast as mineral oil because it seals this stuff on top of the piston where it gets blown out with the exhaust.
With 12,000+ mile oil / filter changes and no build up of gunk inside the engine and no wear, I have to conclude that very little of the nasty stuff gets past the combustion chambers.

 

[buickanddeere]

Synthetics show their advantages in applications with extreme cold, extreme heat or extreme pressure.

 

[John M]

1998 Chevrolet Z71 - 191000 miles and usues not one drop of oil,Oil changed every 5000 give or take
1993 Dodge Dakota right at 230000, oil changes every 4500 - 5000. Still on the road
2001 Ford Dually w/ Powerstroke - right at 80000 - changed every 6000 (Only had it a few years)
2001 Buick Lesabre - Chnaged every 10000 if I catch, 15000 when my wife catches 187000 and still going

These are just some of mine and my friends rides, each uses ....CONVENTIONAL oil. We have fleet rcuks at work with various mileage and engine, non have synthetic or ever have,the one with the least amount of miles is right around 175000.Im done.

 

[Pitch]

When my vehicles manufacturer tells me that they will stand behind extended change intervals, I will start using synthetic. Untill then dino juice changed at every 5000.

 

[Anonymous-0]

Mobil is a great oil! But I don't think they will take care of any warranty issues you MAY have due to extending the drain intervals. Amsoil is a great oil that WILL stand behind their oil and will fight the OEM if there is an issue. They warrant some of their oils for 15k/25k under severe/normal driving and they have a 0w-30w they that will go 17.5k-35k under severe/normal usage. They also sell special filters that are designed to last the life of the oil, made by Donaldson. As someone else noted synthetics really shine in the extremes... heat, cold, stress. They cost more initially but if you go the extended periods they will actually cost less. I gained 1/2 mpg in the wifes 2000 Denali, 1 mpg in my '96 6.5L Chevy Diesel empty and gained a whole 2 mpg with a loaded trailer. My '95 gas Chevy hasn't shown any gains yet. None have used any oil and they all seem to idle smoother especially the diesel. The Denali and Diesel have 12k and 8k on them and the oil is still new lookin in the Denali. Little dirty in the diesel but that goes without saying. I suggest looking into the Amsoil at their website. But like I said before, Mobil is a great oil so don't be afraid to use it but I do know Amsoil will warrant fully thier oils.

 

[Mike M]

Thanks for the disclaimer. But in the end, really, aren't all the posts just opinion ?

 

[Mike M]

I tried it in a couple of things and was not impressed at all !
They were older engines that don't really burn any oil,but with synthetic they started smoking ALOT at startup. Back to reg. oil and all seems ok again.

 

[Steven f/AZ]

My personal experience has been good with synthetic oils. I currently use Mobil 1 exclusively in my vehicles and Mobil Delvac 1 5w-40 in my tractor. I change oil once a year in the tractor and every 6 months in the vehicles, regardless of mileage (usually 6k to 8k). Also, I have switched several high milage engines (150k plus) to synthetic oil without any problems, consumption, or leaks.

Here in AZ where the ambient temp can hit 125 degrees in July and August, I feel that the extra protection of synthetic is a must. In ND, where my tractor is located, the ambient temp can be -35 degrees in January and I fell the extra protection and cold flow characteristics of synthetic is a must.

Having said that, I went many years on whatever was the cheapest on the shelf (usually the SuperTech 5 quart jugs) and using a 3k to 4k interval and never had a problem.

Oil filter study:
http://minimopar.knizefamily.net/oilfilterstudy.html

Synthetic oil study:
http://neptune.spacebears.com/cars/stories/oil-life.html

Excellent oil website:
http://bobistheoilguy.com/

Engine oil "bible":
http://www.carbibles.com/engineoil_bible.html

 

[RobMD]

LOL, yeah.. I was just trying to avoid getting yelled at. Just kidding.

 

[John M]

Well of course they are going to tell you their oil is better, thats called advertising.

 

[Leland]

Schaffer oil has a synthetic oil good for 25,000 miles .the biggest problem is that people forget to change the oil filter every 3000 miles you must do this to keep the oil clean and don't forget the 1/2 qt to fill it back up

 

[Anonymous-0]

I thought you said you were done ? ;-)

 

[RandyB(MI)]

Why would it bother you to get yelled at on the internet??? Are we really that fragile?? Ha! also just kiddin!

 

[John M]

Good one!!!! I just think its sometimes funny when these guys, oil or otherwise, have an FAQ section and it brags about how good their product is. I will admit Mobiles seems to be a bit more general than say Amsoils FAQs, but its still the same in my book.