Oil preference

[Red850kid]

Hey guys! So I'm almost due for an oil change again and I wanted to know everyone's opinion on the type of oil I should use. I'm sure most will say Volvo. So when I first got the car a few years ago I had a oil leak from the cap, rotor, and cps. Upon further research,thanks to this site, I found I had problems in my pcv. So I pulled apart and replaced the system and now most of my oil problems have been resolved. However...I did start at that time using mobile 1 full synthetic oil and I now notice I'm adding like a quart in between oil changes, maybe a a month or two before it's due for a change again. I don't see any obvious leaks and I'm wondering if maybe the engine just "uses" it. Sorry im terrible at introductions, my 850 is a non-turbo.Maybe this engine shouldn't be running synthetic and I may be causing more harm than good. I did do a seafoam flush when I first got the car also. Thanks in advance for any discussion.

[FlyingVolvo]

Most people's oil choices are purely personal preference, and even then, most of those preferences are derived from totally anecdotal and unscientific methods e.g. "it FEELs so much smoother!" & "it just sounds so quiet now!" which are largely BS.

Personally, I use M1 10W-40 High Mileage because my engine is old, has high miles, I drive in "severe conditions" regularly, and costs just a little over $20 for a 5 quart jug at Walmart! My car uses about 1 quart of oil over 5,000 miles.

Give a try to the High Mileage stuff which is supposed to have additives to help swell old seals a little. Slightly higher viscosity may help too. You'll be fine with pretty much any name brand oil. Stick to synthetic with the turbo.

You may officially call this can of worms opened!

[abscate]

You may officially call this can of worms opened!

Its not a can of oily worms, its a barrel of monkey oil

[Red850kid]

Thanks ecbsykes, I'll probably ending up going that route. As I've stated I do run a non-turbo model. As far as the high mileage formula, is that synthetic your using or conventional? Would I be ok to switch back to conventional or is the saying true that one can't go back once you switch?

[FlyingVolvo]

Ah, I read that wrong, sorry. The M1 HM is a full synthetic oil. You should be fine going to syn and back to conventional if needed. There are people who say you can never switch, or that synthetic causes leaks. Again, lots of anecdotal evidence but it's hard to really tell what the causes of problems are in most cases. There may be some truth to an oil that has higher levels of detergents/cleaners causing leaks due to dislodging old gunk on seals. If that's the case though and it starts leaking, the seals are probably bad and wouldn't have lasted much longer anyway.

Don't come yelling at me if something happens... but personally, I'd be comfortable putting a 10W-40 oil like that in your car. You said you've already tried Mobil 1, so I'd just stick with that and try the high mileage variant. Probably can't hurt at this point.

[tryingbe]

I like AMS oil. I use the OE. $4.5 a qt.

[theWIFES_S70]

Rotella T6 5-40... $12 a gallon for a full synthetic oil??

Most drivers will only need three - five gallons a year. That's pretty good if you ask me.

[j-dawg]

You may officially call this can of worms opened!

giphy[1].gif (471.96 KiB) Viewed 1533 times

[erikv11]

Rotella T6 5W-40 in all of my P80 cars (850s and 1998 V70), turbo or non. It's a high quality, inexpensive full synthetic that I am comfortable running all year round in 5k+ OCIs. It's not the only choice but it's a good one and this way I only buy one oil. Except for the S60.

OP, sticking with M1 full synthetic, using 10-40 high mileage is a reasonable way to go. Your car may well be burning oil past the valve stem seals - look for a puff of blue smoke out that back at first startup in the morning, and when you first hit the throttle again after idling for a while at stop lights.