Recommended oil weight for high mileage vehicle?

[Nicholi2789]

Hey guys,
I've used this site alot as a reference but never as a registered member.
Anyways, I have a 1995 subaru legacy 2.2 liter. It has 270,000 miles and climbing and has ran like a top since I bought it a year ago.
Anyways, the vehicle calls for a 5/30 or 10/30 weight of oil. I live on the Oregon Coast and it's very moderate here, never more than 80 degress in summer or less than 30 degrees in winter.
Anyways, I bought it about 15k miles ago and have changed the oil 5 times since owning it. Right at 3k every time.
Anyways, the previous owner used 10/40 so I just continued using that weight. Castrol High mileage 10/40 for the first 3 oil changes, then switched to Mobil 1 full synthetic High mileage 10/40 for the other two. (I'm a firm believer in Mobil 1). Anyways, I know 10/40 is a but heavier than recommended, but I figured it can't hurt with almost 300k miles on it.
Anyways, my question is: am I causing more harm than good using this heavy of an oil? Does it matter? The car amazingly (by some divine miracle) uses only about 1 quart of oil in 3000 miles, which is very little in my experience on a high mileage car, especially a subaru.
What do you guys think? Should I switch to a lighter oil? Am I putting my oil pump through needless torture? How much heavier is 10/40 compared to 5/30 really?
I feel like since it's been working fine might as well keep it, but am scared about the long term effects.
Also, I drive 7 miles Highway to work each way, (15 miles round trip) and always let it warm up for 5 plus minutes every morning.

 

[jacky]

i would use 5-30 hm oil you may even see a slight gas mileage improvement

 

[simple_gifts]

I would use 5w-30 conventional, dispense with the warm up, and assuming the most of your miles are not 'just going to work' miles, extend your oil change interval.

Using mobil 1 for 3K is a waste of your $$, IMHO.

 

[eljefino]

Keep doing what you're doing. How are the oil leaks?

 

[AKhan87]

yes! changing oil every 3k, best way to use your time and money, especially mobil 1.

5w30 to 10w40, I doubt it matters at all.

try 5w30 and compare it to 10w40, difference in the oil burned, if it's the same then use whatever you want.

I think any oil that flows better at colder temperature should be your choice because, I would think that most wear occurs at cold starts.

 

[fdcg27]

I think the M1 HM may be overkill for an engine not known to be hard on oil.
10W-40 is within the grades Subaru recommended for this engine in the original OM, so it should be fine to use.
Subaru used to write that a 5W-30 resource conserving oil was prefered, but would then go on to provide a temp/visc chart allowing for the use of a wide range of grades and would then go even further and allow the use of a straight thirty or forty or a 20W-50 for "severe" conditions.
This is what you'll find in the OM for either our '09 Forester 2.5 or our '99 Legacy 2.2.
The OM allows for the use of a 10W-40 down to about -4F, so you're fine in that regard.
If you want to try something thinner, go for it.
If this engine is only consuming a quart in 3K, you might try a 5W-30 and see how it goes.
OTOH, if the engine is fine on a 10W-40, you don't have much to gain.
You won't even notice the difference in fuel consumption and Subaru apparently felt that the oil pump was equal to the task of moving oils much thicker than any 5W-30.

 

[Bandito440]

It's never cold enough to necessitate idling where you are, so don't bother warming it up. Just get in and drive.

5w-30 or 10w-40; it really won't matter. You might burn a bit more with the lighter oil. Pick whichever. I'd be using the 10w-40 myself.

Oil changes every 3,000 is a waste. Go at least 5,000 unless there's a specific problem. Just remember to monitor the level and top off when necessary.

More importantly, find out the condition of all the other fluids. Coolant, transmission, differential, brake, and power steering fluids should be attended to.

When was the timing belt changed? Those should be done every 90-100k, so your car should be about ready for its third one. Replace the water pump too if you're doing the belt.

Also, keep an eye on the head gaskets. A UOA will show if they're starting to go.

 

[Pontual]

10w40 is a great oil for a 1995 Subaru.

 

[Kuato]

Originally Posted By: Nicholi2789
Hey guys,
I've used this site alot as a reference but never as a registered member.
Anyways, I have a 1995 subaru legacy 2.2 liter. It has 270,000 miles and climbing and has ran like a top since I bought it a year ago.
Anyways, the vehicle calls for a 5/30 or 10/30 weight of oil. I live on the Oregon Coast and it's very moderate here, never more than 80 degress in summer or less than 30 degrees in winter.
Anyways, I bought it about 15k miles ago and have changed the oil 5 times since owning it. Right at 3k every time.
Anyways, the previous owner used 10/40 so I just continued using that weight. Castrol High mileage 10/40 for the first 3 oil changes, then switched to Mobil 1 full synthetic High mileage 10/40 for the other two. (I'm a firm believer in Mobil 1). Anyways, I know 10/40 is a but heavier than recommended, but I figured it can't hurt with almost 300k miles on it.
Anyways, my question is: am I causing more harm than good using this heavy of an oil? Does it matter? The car amazingly (by some divine miracle) uses only about 1 quart of oil in 3000 miles, which is very little in my experience on a high mileage car, especially a subaru.
What do you guys think? Should I switch to a lighter oil? Am I putting my oil pump through needless torture? How much heavier is 10/40 compared to 5/30 really?
I feel like since it's been working fine might as well keep it, but am scared about the long term effects.
Also, I drive 7 miles Highway to work each way, (15 miles round trip) and always let it warm up for 5 plus minutes every morning.


First of all,

!

With low consumption like that and nearly 300k miles, sticking with what has worked IMO is a good option. Maybe go with a 5w40 or even M1's excellent 0w40.

I agree with skipping the 5 minute warm up, as well as a somewhat longer interval.

 

[Hollow]

All that warm up does is waste gas. Stop it.

Check your PCV, it can cause crazy oil consumption when it clogs.

Those 2.2 are very easy on oil. Any name brand 5w30 or 10w30 should be able to go 5000 easy. I'd go for QS Defy or Pennzoil HM myself.

 

[sicko]

You're fine using 10w-40. It's not going to do anything bad.

However, I would either reconsider using M1, or the oil change interval that you're using.

I'd either drop it down to conventional such as Mobil Super 5000, or I would increase the oil change interval. On synthetic you can easily go 5k miles on that engine, conventional will probably go 5k thousand as well (especially because you're putting 1 quart every 3k miles into it), but maybe you should do it at 4k miles until you get comfortable with extending it that long.

 

[SnowDrifter]

Check oil pressure and go from there IMO. Even if the tolerances are sloppy and need a thicker oil to maintain pressure, you can drive a heckuvalot more miles in that state with good maintenence

 

[Oro_O]

May or may not help, but another data point.

I live in western WA and have a 2002 ES300, with a toyota V6, 235k miles. I've thought it through and I like 5w-30 vs. a 10w-xx for better cold start protection, even in our (same) mild climate. I use M1 5w-30 HM mostly. It burned 8 ozs. or so in the last 7.5k OCI with that. So it clearly doesn't increase consumption from my experience. Currently have PP 5w-30 in it (had some on the shelf at home) and after 1.5k on that, there is no visible usage.

I let a car idle 30 seconds when cold, then just drive to keep it under 2k rpm until the coolant temp is coming near normal. I've done some research into "warm up" and found that to be a widely recommended pattern from people who seem to know.

 

[JimPghPA]

If it was mine, I would run the new Castrol 0W-40 and go for 8K or 3 years which ever came first. Of course be sure to top it off every 1 to 3K or so (when it gets to a half quart low).

 

[Nicholi2789]

Hey guys, wow, Thanks for all the responses and input.
Where do I begin replying to all this? haha.
First off, I have to say I am listening to your advice and taking it into consideration but I must say I disagree with not letting it warm up. True, maybe 5 minutes is excessive, the but way this car drives when it's cold compared to warmed up is night and day. When cold it's super sluggish and drives like [censored]. Plus, I am a firm believer in letting that oil circulate a bit before taking off, I may shorten it to like 2 minutes but I will always let it warm up.

And as far as using Mobil 1 and changing it every 3k miles. I know that it's extreme overkill, and that oil is good for 10K, I just really need this car to last and spending the extra 8$ on a gallon of full synthetic and having superior protection is worth it to me. Even if I am still changing it at 3K. I know that the old 3000 miles rule of thumb is extremely outdated, but I just like to play it safe. I take the used oil to a local lube shop and it get's recycled and re-refined so it's not a total waste.
I may bump it to 5K miles and see how it does, but I don't think I could stand going longer. I'm too OCD for that. lol. I should at least go 5K though considering I use the Fram UltraGuard filter too.

@Kuato: Obviously I need to do some reading and get a better understanding of multi-grade oils because I always thought 5W/40 and 0W/40 were for just European cars and sports cars. lol. Would you really recommend a 5W/40?

Also, @Bandito440:
I have nearly changed every fluid in this car since I bought it a year ago. Flushed the coolant, Power steering fluid. Changed the rear differential fluid, changed the manual transmission fluid, changed the oil many times, spark plugs, wires, fuel filter. And I did the PCV valve.
When I first got the car the bottom of the engine was covered in oil. Leaking from cam/crank seals, valve covers, and from the Oil seperator plate in the back. I also had no idea of maintenance on this thing so I resolved to do the timing belt. I tackled that this month. Replaced all the cam seals, crank seal, all the timing components (belt, pulleys, etc), new water pump, also pulled the oil pump off, cleaned it, and tightened the screws on the backing plate (notorious for loosening). It took me 7 hours but I got it done by myself. Lol. Super proud of myself. It no longer leaks any oil from the front of the engine.
What really baffles me, is that the car looked like it leaked a ton of oil, but I never went though more than a quart or quart and a half in my OCIs.
And no, it has no signs of Head Gasket problems. The phase 1 2.2 liters weren't really known for that. It was mostly the phase 2 2.5 liters between 97-2003 or so. Though others were affected too. I was worried about that for a time too since I heard all about the Subaru headgasket problems.
This car has been the best 700$ I have ever spent.
Oh and one last question: Can a heavier oil really cause a drop in fuel economy?
My gas mileage has always been [censored], but I ask other Subie owners and for these cars in the 1990-2000 era 25-38 mpg highway seems about typical. I get considerably less in town.

 

[Oro_O]

Sounds like you did a lot of good work.

I wonder though, if all things are tended to as you describe, and your mileage is horrible and the car won't warm up or run correctly off the bat, - if there isn't something else wrong. Thermostat stuck open, air leak in intake, etc.

1995 is pre-OBDII and you don't have the array of diagnostic assistance that 1996 and up would give you.

 

[Joe_Power]

Try Rotella 15-40. See how your car likes it...

 

[Bandito440]

Originally Posted By: Or
Sounds like you did a lot of good work.

I wonder though, if all things are tended to as you describe, and your mileage is horrible and the car won't warm up or run correctly off the bat, - if there isn't something else wrong. Thermostat stuck open, air leak in intake, etc.

Something worth checking.

Using M1 10w-40 HM over the 5w-30 might reduce your fuel economy by 2%, which you aren't likely to notice. I say stick with the 10w-40.

Overall, you're on the right track.

 

[Nicholi2789]

Originally Posted By: Or
Sounds like you did a lot of good work.

I wonder though, if all things are tended to as you describe, and your mileage is horrible and the car won't warm up or run correctly off the bat, - if there isn't something else wrong. Thermostat stuck open, air leak in intake, etc.

1995 is pre-OBDII and you don't have the array of diagnostic assistance that 1996 and up would give you.

You are correct, but you are also incorrect.
1995 on Subaru IS OBD2. I know that it wasn't a requirment until 96, but Subaru got a headstart and put it in all their 95 cars. My Car has an OB2 port and my check engine light only ever came on once because of a bad knock sensor. Otherwise I have been completely code free.
And it does run correctly off the bat, it just idles at about 1500 RPMs for a minute or two, then drops down to it's normal 700 RPMs. I just don't like driving it cold cause it's so sluggish. The thermostat is brand new, replaced it with an OEM one when I did the t-belt, and i've already checked all my PCV lines and intake hose for clogs or holes. Nothing there.
When I replaced the spark plugs I used regular Autolite coppers (that's what the Autolite book recommended) but now I've done alot of reading and a lot of experienced Subaru guys say to use only the factory recommended NGK plugs or you will get [censored] mileage, and less power. So that's the next step.
It's also worth mentioning that I only use non-ethanol fuel. I used to run regular unleaded but I tried non-ethanol for a while and noticed a dramatic difference. I got about 2-3 MPGs better, and more power (I can go 75 mph in fifth gear up a hill I used to only be able to do about 55 up), and the car all around runs better. I'm a firm believer in non-ethanol gas. Run it in all my chainsaws too to the same effect. Yeah it is more expensive, and the extra cost probably counters the extra couple MPGs, but it's worth it for the power and consistancy. I've been running non-ethanol only for about 9 months now.

 

[Nicholi2789]

Originally Posted By: Bandito440
Originally Posted By: Or
Sounds like you did a lot of good work.

I wonder though, if all things are tended to as you describe, and your mileage is horrible and the car won't warm up or run correctly off the bat, - if there isn't something else wrong. Thermostat stuck open, air leak in intake, etc.

Something worth checking.

Using M1 10w-40 HM over the 5w-30 might reduce your fuel economy by 2%, which you aren't likely to notice. I say stick with the 10w-40.

Overall, you're on the right track.

Thank you! That was my thought also. If 10/40 has been working good all this time, why change it? But then I thought maybe there are some ill effects I don't know about or something else. That's why I resolved to post here and ask the pros. I am kind of curious about running synthetic 5w/40 though..