HYPER low mi/short trips: conventional or synth?

[wemay]

Originally Posted By: Quattro Pete
Originally Posted By: KrisZ
The fuel and moisture buildup can only be dealt with one way, by changing the oil. There is no documentation that proves synthetics better deal with viscosity loss due to fuel and moisture. Both conventionals and synthetics are equally affected by it.

Agreed.


+2

 

[Quartz]

Originally Posted By: Quattro Pete
What are the lowest temps that you experience at which the engine will be started?

That depends- I'm pretty sure the garage never gets below freezing, so usually the first start isn't that bad. However if I'm parked outside it could easily be sub-zero F in the dead of winter.

Originally Posted By: Quattro Pete
At the rate you're going, your car will die of a number of other issues such as electrical or rust, rather than of engine lubrication problem.

Very likely true, but given my weird driving situation I'd like to give it a fair shot at lasting.


Originally Posted By: Quattro Pete
can you provide year/make/model for us?

It's a 2007 volvo xc70. I figured not everyone would know offhand what engine it was, so stating the 5cyl+turbo directly was more important. (Although as it turns out everyone guessed it anyway)

 

[Quattro Pete]

Originally Posted By: Quartz
It's a 2007 volvo xc70.

Thanks. Nice car.

If I was in that situation, I'd probably run something like M1 0w-30 and change it once a year. It meets ACEA A1/B1 which your owner's manual mentions.

You don't need Xw-40 grade, unless you take your car to the track, IMO.

 

[Quartz]

Originally Posted By: Quattro Pete
You don't need Xw-40 grade, unless you take your car to the track, IMO.

I'm still not 100% sure I understand how oil weights work. Correct me if I'm wrong, but doesn't -30 max out around 85F whereas -40 is good up to 100F? It occasionally gets into the 90's in the summer here, and since most of my driving is stop-and-go around town I worry that -30 might not be right.

 

[KrisZ]

Originally Posted By: Quartz
I'm not worried about viscosity loss, I'm worried about condensation from short trips resulting in acid buildup causing corrosion.... although there seems to be mixed feelings here as to whether synthetics fight that better.


Then no one can answer this for you. The only way to get an answer, in your situation, is to do at least one UOA, more is better to establish a trend, and see how much TBN is left at the end of each OCI. As long as the TBN number remains above 1, the acids will be neutralized. Both conventional and synthetic oils work the same in this regard.

However, most oils have enough TBN for an annual OCI. A 6 month OCI is more than enough for any oil to handle and not deplete its TBN, even under the most severe service. So unless your owner's manual shows less then 6 months OCIs for severe service, I would not waste money on UOAs and just change the oil at the specified intervals.

 

[KrisZ]

Originally Posted By: Quartz
Originally Posted By: Quattro Pete
You don't need Xw-40 grade, unless you take your car to the track, IMO.

I'm still not 100% sure I understand how oil weights work. Correct me if I'm wrong, but doesn't -30 max out around 85F whereas -40 is good up to 100F? It occasionally gets into the 90's in the summer here, and since most of my driving is stop-and-go around town I worry that -30 might not be right.


What does your manual state? My Mazda 3, for example, can run 5w20 oil in all operating conditions. This means outside temps above 100F.
The number after "W" is manufacturer's specific recommended viscosity, not a generic outside operating temperature rating. That rating is for the number that is before "W".

 

[Quartz]

Originally Posted By: KrisZ
So unless your owner's manual shows less then 6 months OCIs for severe service

Part of the problem is that it doesn't have hardly any info for service schedules, not even a "typical" one. It just says no more than 7500mi/12mon, and that I can swap to synth 0w-30 or 0w-40 if my use is 'extreme'. That's literally it, like one paragraph and a picture of an API donut.

 

[mazdamonky]

I would just run the factory recommended weight conventional for 1 year/5k miles or the factory recommended weight in a synthetic for 2 years/10k miles. But you have what sounds like a fun car. Get it out and drive it every once in a while to enjoy it. Some people see cars as just a tool. Those have less fun in life than those who see it as a toy you just want to last as long as possible.

 

[Quartz]

Originally Posted By: KrisZ
What does your manual state?

Honestly not a lot. Normal is conventional 5w-30, but I can switch to synth 0w-30 or 0w-40 if I want. Most of the people in this thread are saying synth, and AFAIK conventional 5w-30 is only good up to about 85F, so I thought 0w-40 was the better choice.

 

[Quartz]

Originally Posted By: mazdamonky
I would just run the factory recommended weight conventional for 1 year/5k miles or the factory recommended weight in a synthetic for 2 years/10k miles.

See, I'm not sure what to do here. Opinion (both here and others I talk to) seems split between 6months or 12 or what. If I were putting all couple hundred miles on in like two or three trips it would be one thing, but the short trips condensation issue really makes me question leaving the oil in there for very long.

Originally Posted By: mazdamonky
But you have what sounds like a fun car.

lolwat

It's a family wagon with more cup holders than seats. I do wish they made a reasonably priced AWD performance wagon though, I miss my old sports cars sometimes (but not in winter).

 

[kschachn]

Originally Posted By: Quartz
Originally Posted By: KrisZ
What does your manual state?

Honestly not a lot. Normal is conventional 5w-30, but I can switch to synth 0w-30 or 0w-40 if I want. Most of the people in this thread are saying synth, and AFAIK conventional 5w-30 is only good up to about 85F, so I thought 0w-40 was the better choice.


I honestly don't get where some of these OM recommendations come from. For one I think they are holdovers from ancient days when oil was a lot less capable than it is today.

Just use the 0W-40 and be done with it.

 

[cmhj]

Why re-invent the wheel?

 

[KrisZ]

Originally Posted By: mazdamonky
Some people see cars as just a tool. Those have less fun in life than those who see it as a toy you just want to last as long as possible.


IDK, worrying about something as inconsequential, in the grand scheme of things, as whether to use synthetic oil or conventional, or 0wXX vs. 5wXX, doesn't sound like a whole lot of fun to me.
I'd rather pick an oil and enjoy the car, fully knowing that the car is a tool and the oil a commodity.

 

[Quattro Pete]

Originally Posted By: Quartz

I'm still not 100% sure I understand how oil weights work. Correct me if I'm wrong, but doesn't -30 max out around 85F whereas -40 is good up to 100F?

No, it does not mean that.

The "30" or "40" number AFTER the W represents ranges of kinematic viscosity at 100C, which is 212F, which is typical engine operating temperature after the oil had a chance to fully warm up. That operating temperature will not be much different regardless if the ambient temperature is 85F or 100F because your engine has a cooling system that regulates it.

However, if you drove the car like you stole it for extended periods of time (like you would do if you were on a race track), engine temp would increase somewhat above 100C/212F, and that's when a "Xw-40" grade oil would provide more protection.

 

[mazdamonky]

Originally Posted By: KrisZ
Originally Posted By: mazdamonky
Some people see cars as just a tool. Those have less fun in life than those who see it as a toy you just want to last as long as possible.


IDK, worrying about something as inconsequential, in the grand scheme of things, as whether to use synthetic oil or conventional, or 0wXX vs. 5wXX, doesn't sound like a whole lot of fun to me.
I'd rather pick an oil and enjoy the car, fully knowing that the car is a tool and the oil a commodity.


That is almost exactly what I am getting at. Pick a good name brand oil and don't worry.

 

[Quartz]

Originally Posted By: Quattro Pete
Originally Posted By: Quartz

I'm still not 100% sure I understand how oil weights work. Correct me if I'm wrong, but doesn't -30 max out around 85F whereas -40 is good up to 100F?

No, it does not mean that.

I mean, I know that the -XX is not a direct indication of what temperatures it's good for, but I thought that in relation to 0w- and 5w-, a -40 was good to ~100 whereas a -30 was only good up to ~85.

 

[mazdamonky]

Originally Posted By: Quartz
Originally Posted By: mazdamonky
I would just run the factory recommended weight conventional for 1 year/5k miles or the factory recommended weight in a synthetic for 2 years/10k miles.

See, I'm not sure what to do here. Opinion (both here and others I talk to) seems split between 6months or 12 or what. If I were putting all couple hundred miles on in like two or three trips it would be one thing, but the short trips condensation issue really makes me question leaving the oil in there for very long.

Originally Posted By: mazdamonky
But you have what sounds like a fun car.

lolwat

It's a family wagon with more cup holders than seats. I do wish they made a reasonably priced AWD performance wagon though, I miss my old sports cars sometimes (but not in winter).


If the manual says conventional is good for one year, then I see no reason not to follow it. If you REALLY are worried about it then get a UOA to see what it shows.


These wagons handle quite well in my experience. Not saying sling it around corners at double the recommended speed, but a spirited drive with a little pedal pushing is even fun in a Geo Metro loaded with bricks.

 

[Quattro Pete]

Originally Posted By: Quartz
Originally Posted By: Quattro Pete
Originally Posted By: Quartz

I'm still not 100% sure I understand how oil weights work. Correct me if I'm wrong, but doesn't -30 max out around 85F whereas -40 is good up to 100F?

No, it does not mean that.

I mean, I know that the -XX is not a direct indication of what temperatures it's good for, but I thought that in relation to 0w- and 5w-, a -40 was good to ~100 whereas a -30 was only good up to ~85.

Now you completely lost me.

 

[kschachn]

Originally Posted By: Quattro Pete
Now you completely lost me.


I think he means the arrows on the oil selection chart in his owner's manual only go that high for the -30 and the -40. Which is what I was getting at with my comment about those charts and being more or less useless.

If of course that is what he means.

 

[Quartz]

Originally Posted By: mazdamonky
If the manual says conventional is good for one year,

A maximum of one year (or 7500mi, whichever is first). This implies to me that they want you to change it more often than that (although it doesn't say how much more often). That's one of the reasons I'm leaning towards six months.