I change my oil every 3K miles, always. I also change tranny fluid every 10 - 12K miles (anually). Now, is there any real advantage to use syn with these intervals? I don't drive the cars (2 97 850 GLT Turbos) hard. I have changed the air filters to Knb's. I always run 91 octane..... I put BG 44K in the gas twice a year, and add a BG tranny conditioner each change. It costs, $43 to do a tranny flush, and $16 for an oil change. The BG44K is $40/year. What would the advantage be to go to syn. One car has 40K and the other 80K. These costs are per car. Would going to syn be kind of getting to the point of diminishing returns?
So my anual costs for this is:

Oil 3 X $16 = $48
Tranny 1 X $43 = $43
BG additives 2 X $20 = $40
Annual costs $131

X 2 cars $262

Thanks....

Use a good synthetic. If you don't trust the recommended drain period, use oil analysis to set your own drain.
Use the Mobil 1 Tri-synthetic you have. It is not going to do any harm, and is better than most oils on the market, though in some ways not as good as it's predecessor formulation. Don't really know about the new stuff. Mobil is one of the few companies which still uses the better (and pricier) PAO base stock, which is a group IV oil. Castrol uses Group III.

I recently switched over to Castrol Syntec and my car runs smoother than ever, and feels like it picked up a couple horses. I change the oil every 3k, and will stick with Castrol Syntec 10W-30. They should have it available at your Volvo dealership.

--
'95 Volvo 854 Turbo: Gold Edition
K&N Air Filter, Leather, 6 disc CD-changer, Rear Spoiler

At 3k miles I might stick with a good dino oil. I have the HP turbo and do occasionally drive hard so synthetic at 5k is what I do. It all comes down to what are you comfortable with. With 10-12k miles of easy driving per year I think that Dino oil at 3k will be fine.

That's my 2 cents worth.
--
Nathan Valles, Black 855R, Tint

I follow Volvo's recommendation: 5,000 mile oil changes for my '98 T5. I use synthetic oil, since it's a turbo. I don't change my oil more often because 1.) I use synthetic oil 2.) I figure Volvo manufacured the car, it's possible their engineers know something 3.) the material cost of 6 quarts of dino juice, a oil filter and an aluminum washer would approximate the extra cost of the synthetic oil. That is, if I valued my time at $0/hour. 4.) my oil is usually not appreciably "dirty" when I change it 5.) in the grand scheme of conservation, including the conservation of my own time and money I think more frequent changes would be a waste. Anyway, I now have 95,000 miles on my car and it uses no oil between changes, not a drop. This is similar to the patterns my previous SAABs exhibited with 3750 mile dino juice changes.

-Punxsutawney Phil

http://www.groundhog.org

What kind of syn do you use? The Mobile 1 5W30 isn't true syn, yet they are charging as if it were.. Thanks.

They charge whatever the market would bear (are CDs still worth $20?).
Mobil1 tri-synthetic wasn't "true" synthetic either but it seems that since the newer formulation arrived it's strirred more controversy as we now elevate the old Mobil1 to full synthetic status and dispair over its lose. So, if it wasn't 100% synthetic before what's the problem now? Maybe the super refined dino juices are better than PAO base stock or maybe the new concoctions that Mobil is peddling are better than Amsoil ones. There is just too little information to decide that the new formulation will not work as well, or maybe better, as the old one, and better than 100% pure synthetic oils.
Whether the oil is formulated with 100% sythetic base stocks (PAO) or a mixture of super refined dino oils matters very little as engines know nothing about chemistry but everything about lubrication, wear, viscosity, pumpability, corrosion, etc. The old Mobil1 5W30 had pour point of -65F (was it better than Amsoil (100% synthetic) back then?) and now is -54F (Amsoil 5W30, still 100% synthetic, is -60F), pumpability limit for "new" Mobil1 5W30 is -51F (Amsoil is -40F). I don't think it makes any of the oils any better or worse than the other because what also counts are the additives that keep the engines in good conditions while maintaining oil properties between changes. So, if Mobil1 cocktail is as good or may be even better than Amsoil over 5,000 miles then what's the point of stressing the significance of using "pure" synthetic base stock (PAO) as great majority of car owners will go for regular drain interval (5,000 miles) whether they use dino, semi, or fully synthetic (whatever that term now means) and that is what prompted, apart from the bottom line, Mobil to reformulate its "synthetic" oils twice already. The main reason for switching to "synthetics" is cold weather lubrication, long term stability, and high temperature protection (turbo engines) and extended drain intervals that some of the "pure" synthetic use as a selling point, come distant four, if at all.
I use Mobil1 and Castrol Synthec with 5,000 mile drain intervals and have Mobil1 ATF in my tranny. I think that low pour point, low pumpability limit, high temperature protecton, oxidation resistance are worth the additional expense that no shortening drain intervals with conventional dino oil will accomplish. But if in your case the properties don't matter, than probably the maintenance procedure you follow and dino oils will keep your car in excellent condition for many years.
Good luck.

Good points. One can over think these items. Thanks for the input...

I still have 3 cases of "vintage 2001" Mobil 1 10W30 tri-synthetic. I tend to buy a few cases at a time because the discounter where I buy it doesn't always have it in stock. I'll decide what to do after the smoke clears. BTW, I've heard BMW dealers sell synthetic oil cheaper than almost anyone else. It's branded "BMW".

-Punxsutawney Phil

http://www.groundhog.org

I ahve read somewhere that it's a blend, Casrol I think......

hi ya all,

Yes Castrol is a blended oil. If you read a report that Charles of Volvospeed mentions, a test on oil at some lab in the US you will see why your should change your oil often. I personally use fully synthetic and in the old days used to do it myself but my local car service chain did it cheap than i can be all the bits for, oil, filter disposal.

I now have 174k on my 94 850 and thinks its worth the money as i wish to keep her. I do push my oil changes though some months when i have done 10k in three months tops but i have changed the filter at least twice in this period, before the full job.

mark in the uk.
uk voc 94 850glt 2l 20v 174k, new clutch,t5r bumper, k+n, Volvo Brace, slots.

BTW if anyone's wondering about the shelf life of syns [I had a bunch of M1 on hand], I rung up Mobil and the guy I talked to (I hope he wasn't the janitor passing through the tech support section en route to his next gig) said if it's been sitting awhile, just shake it well before pouring.
Don [T-5R & V70]