How often do you change your synthetic oil?

I change mine (Mobil 1 10w-30 and filter) every 4 months or 3333 miles, whichever comes first.

You don't mention where you do your driving so I can't provide any specific recommendations.

Volvo recommends changing the oil every 7500 miles for a car in normal service, even if you only use regular (non-synthetic) oil. I use synthetic oil and so I feel like I have plenty margin of safety following Volvo's 7500 mile recommendation.

In a non-turbo I wouldn't even use synthetic, perhaps a partial synthetic if you want something a little better. Still depends how you drive it though, but I would say 6k miles or 6 months would be a good number.

Same oil (Mobil 1 10w30), I change it every 4 months or so with the filter. I don't worry about mileage, because it is always 5000-7000 miles.

I drive 10 miles each way to work, no hills but some traffic, and then there are other incidental trips across town, and finally one long highway drive (several hours) at least once per oil change. I think you could argue either way that this fits the "severe" or "normal" schedules...

"In a non-turbo I wouldn't even use synthetic". WHY???

The car is non-turbo. I drive, well, aggressively I guess. Speeding is not my type, but I do "quick" start and don't follow...

I thought 6 m>

Well I only run synthetic in turbos because they benefit most from it, the extremely high speed and temperatures they run at, combined with the higher overall stress and heat in the engine can really cause standard oil to coke up fast. We've got several N/A Volvos in the family with well over 200k on dino oil so it just seems the added cost of synthetic for those is not worth it. Granted it certainly won't hurt to use it.

According to what I've read, most of the breakdown of oil is because of heat. Since synth oil breaks down at a much higher point then dino oil, you can just change your filter at the prescribed time, and the synth oil itself can be changed less often. There's lots of info on this around the web, with plenty of people sending their oil off for analysis to prove the point. I've heard of synth users going 30k or more on Amsoil, with only a filter change and a top up. The oil actually shows up cleaner after the filter change, and each time the filter is changed it's cleaner still. The filter grabs the particulate, and the oil just keeps cleaning up in there. I know this from my own experience with Amsoil in my 87 turbo. My cam is starting to look really nice in there...:-) And, I agree with James, why use synth on an NA car, unless you want to go

20k (or more) between changes? You don't get the heat of a turbo, in there, so regular dino will be fine, IMHO.

RS

I agree about the reduced heat load in a non-turbo engine, but I pay for synthetic in my car because there is nonexistant sludge buildup compared to conventional oil.

Here are two results that directly relate to Volvos, and probably several other makes and models- Less maintenance is required on the crankcase ventilation (flame trap), which is very convenient. It clogs up much less or not at all. In the case of the 850 engine family, the valve lifters tend to stick if the engine is not revved hard every few weeks. Synthetic oil pretty much eliminates this albeit minor problem.

All the 20 valve 5 cylinders seem to get sluggish and lethargic if they aren't driven hard for a few miles every couple of weeks or so in my experience. Computer shows a drop in mpg too.

Just sold a 93 850 with 120k on it, oil changes every 5k with good quality mineral 15w-40 from new- didnt loose a drop between changes, all the lifters totally silent and insides clean enough to eat your dinner off. Still as happy to spin to the red line as when it was new.

As a comparision, have just dropped a new (used) motor into a V90 with 170k on the clock. This has had variable oil change intervals from 10k to the-owner-wouldnt-admit-how-many-miles. Engine was totally shot. At cold start it was only running on five cylinders- and 3 or 4 lifters were pretty noisy whilst it was going. Ran a big end by the sound of it and was rattling like hell, then tightened up and wouldnt restart.

Bottom line is if you want the engine to go the distance you have to change the oil!!!

Tim..

When i cleaned the flame trap on my 91 940NA it barely need cleaning. This was after about 163 K on regular changed dino oil. I'm going to try synthetics next oil change wich is soon, because there's a special offer on FINA 5W-40 oil here now. I'm curious if I will feel a difference on the engine

What kinds of oil did both of you use? I'm asking out of curiosity- my complements on taking care of your engines.

I've been changing mine every six months or 5,000 miles which is the Volvo severe duty recommendation for our 850. I figure that if I go with the severe duty schedule I have more than enough overkill :).

If you want to get some data, do an oil analysis after your next normal for you change interval. Blackstone Labs

willdo an oil analysis with TBN measurement for around $25 and that will tellyou not only if you are changing your early at appropriate time, but also ifthere are certain lurking problems with your engine. Well worth the money to have real information about your situation rather than just getting opinions from people.

John

Why use synthetic? If you change at that frequency, you could use Mazola or any cheesy house brand oil.

You're just pissing away money.

Same reason many people buy life insurance, they just don't know when the big event is going to happen with any large degree of certainty. Thus, they decide to buy the insurance.

P.S. $90/year for Mobil 1 and filters (I change it myself) does not seem to be that much money when you think about how many people spend that much in a month on beer and/or cigarettes.

(snip)

Mobil 1, 5 quart container at Wal-Mart = $23.00+Pure 1 oil filter @ ~$ 6.00$29 per oil change (DIMS) each 5000 mile change. Three times per year = $87

No particular brand. Recently i've bought semi syntecis from my local auto store

Personally i wouldnt switch to a fully synth on an engine like this, as its too thin, and you'll end up with it pissing out from every orifice. If it aint broke dont..... etc.

Keep using the mineral oil- 15w-40 or whatever for your temperature of a G4 or G5 / A3 or A4 / SH or SJ quality rating.

Tim..