[rasterman]

No, synthetic usually finds its way through even smaller gaps and can thus leak/burn more in an engine that is already losing some oil.

Without a true synthetic requirement (manufacturer's declaration, extreme cold temps, extreme duty or very long OCIs) I'd say stick to what you're doing. Any current API-rated motor oil exceeds the specs that were in effect in 2006.

You might as well stick with the cheap stuff since you'll be buying more of it.

 

[subaruman49]

Thats what I thought....thanks rasterman....................

 

[AWDFTW]

I'd say you're changing your oil too often unless the car sees pretty severe service.

Owner's manual calls for 7500 miles/7.5 months normal or 3750 miles/3.75 months severe service.

5k-8k is easily doable with a quality conventional oil.

Why does her car use that much oil? How long time/miles to use 1.5 quarts?
Consumption? Check PVC.
Leaking?

 

[subaruman49]

I think there is a leak.....but when I changed oil Saturday I saw nothing underneath...dry.................very strange.........I do not see any blue smoke at any time...car is in excellent condition...........but something is going on...it also has started to surge" every now and then...but once warmed up no problem...might be throttle sensor...like on my 2003 Bean H6.... I will check PVC....Thank you.much appreciated

 

[ScoobyRu]

It probably uses that much oil because it's a Subaru. :jester:

Seriously though, mine uses the same amount. I don't know why (well, I have a guess: piston oil rings). I just this weekend repaired a few oil seeps (valve cover gaskets, spark plug tube gaskets, oil sensor threads). I also replaced the PCV valve.

We'll see if the PCV makes a difference.

Here's what I do know: Don't extend your OCI. My oil consumption shoots through the roof the more miles I put on an OCI. My Subaru would seize well before I reached 7500 miles.

 

[SE95]

I change my oil religiously every 3,000 miles (although this last time I let it go to 3,800 miles due to lack of time/facilities to change it). I use a value branded full synthetic 5W30 (Parts Master) and a WIX premium oil filter. My Outback uses about a half a quart between oil changes, and my guess is that is coming out of the valve cover gaskets (at least that's what it looks like from underneath).

 

[TooSlick]

Conventional oil is less expensive per quart - that's the only advantage I can see. Of course I've been using synthetic oil in everything I own since 1978. So I admit to a certain bias.

If your engine is leaking like a sieve and/or is worn out internally, I'd stick to petroleum oil. But aside from that the top tier synthetics are better in every measurable way. Any decent synthetic (Mobil 1/Extended Performance, Pennzoil Ultra, Castrol Edge, etc), will easily last for 7500 miles in a non turbo Subaru engine.

TS

 

[SE95]

I actually sent an oil sample in from that last oil change to Blackstone. I am awaiting the results.

 

[subaruman49]

Thank you for all the replies...............I think I'll stick with regular oil every 3000 miles..I have been doing this for OVER 30 years....and so far so good............. will have to inspect further my wifes 2006 2.5 oil loss...............appreciate your input...

 

[AWDFTW]

I realize no one typically listens when trying to talk about why the 3000 mile oil change is outdated, but I'll throw the information out there anyway.

Oil now is better than 1970's oil. It can and does hold up longer than 3000 miles, there are hundered of Used Oil Analysis tests that can show this. I suggest the website Bobistheoilguy.com for a TON of information.

3000 mile changes are a commonly waste of resources, both your own finances and the oil itself. For what it is worth, you cannot put a price on peace of mind, but I do think being informed is a good thing.


The only way to find out what is good for your car is to have data. I have had a UOA done, and the particular oil I have now is good for about 7000 miles in my conditions. That being said, there are better oils than can go for 10, 15, 25 thousand miles in the proper circumstances, and some oils that will be spent by 5 thousand in other engines.

So, really the 3000 mile change is a standard created by oil change services to sell you more product based on a severely outdated service interval and product (comparing API SF rated oil with modern API SN).

 

[SE95]

My reasoning for still doing 3,000 mile intervals even on synthetic is that for me it is cheap insurance. A $30 oil change now versus a $1000+ repair later. You do the math. I can probably go to at least 5,000 miles and be fine, but my other problem is the fact that the oil is BLACK and smells dirty after as little as 500 miles. I realize this does not necessarily have anything to do with the lubricity of the oil, it is more just letting you know that the oil is doing its job and cleaning the engine. But it still scares me a bit. That's why I sent an oil sample into Blackstone for analysis, I want to know what is going on with my oil.

 

[subiesailor]

My reasoning for still doing 3,000 mile intervals even on synthetic is that for me it is cheap insurance. A $30 oil change now versus a $1000+ repair later. You do the math. I can probably go to at least 5,000 miles and be fine, but my other problem is the fact that the oil is BLACK and smells dirty after as little as 500 miles. I realize this does not necessarily have anything to do with the lubricity of the oil, it is more just letting you know that the oil is doing its job and cleaning the engine. But it still scares me a bit. That's why I sent an oil sample into Blackstone for analysis, I want to know what is going on with my oil.

Your waisting money - time and oil so knock it off. ;-) Even my dirty 2001 which saw the worst case use was changed out at 4000-5000 miles and when I sold it at 180,000 miles it had zero oil related issues and ran like a champ. I say dirty because compared to my 2010 the old 2001 2.5 was exceptionally hard on the oil vs the 2010 seems much cleaner and not anywhere as close to as hard on oil as the old 2001 was.

 

[SE95]

Again, cheap insurance. $30 every few months isn't a lot of money for peace of mind. And I'll wait for my oil analysis to come back before I make any rash decisions.

 

[Performance Suby]

I too change my oil every 3000-4000 miles with 5w30 synthetic, but I only travel that amount of mileage in about 6 months. Even after 3000 miles my oil is still a medium brown color and not black and the engine doesn't use any oil at all. I'd rather spend $60 a year for 2 oil change to keep my peace of mind, but thats just my opinion.

 

[TooSlick]

Just wanted to add, there are a lot of very average "synthetic" oils out there. A large percentage of the Group 3 base stocks are sourced from South Korea and don't have very good physical or chemical properties. It's most often used in the cheaper off brand and private label synthetics. By contrast, Royal Dutch Shell(Pennzoil), ExxonMobil (Mobil 1) and Petro Canada (Duron), all synthesize high quality, low volatility, high viscosity index, Group 3 oils. If you're going to spend extra for synthetic, I'd highly recommend using one of the synthetics derived from these superior, Group 3 base oils.

TS

 

[BadAV]

I'll add a little to the conversation. I've run nothing but synthetic oil since about 1995 in anything I own that has a motor.

The GM 3.6L DI has proven to be very hard on oil (shearing - breaking the oil down in 5k miles); there have been quite a few Blackstone Labs UOAs done. For a cheap synthetic, Pennzoil Platinum (PP) has proven to be quite good; standard Mobil 1, not so much. I've converted to PP. That said, Valvoline standard 5W30 has also held up very well. I do my own maintenance; the way I look at it, I know it's done right and I can use synthetic oil and premium filter for about the price of bulk oil and no-name filter at a quick-lube joint.

 

[AltaBrig]

I'll add a little to the conversation. I've run nothing but synthetic oil since about 1995 in anything I own that has a motor.

The GM 3.6L DI has proven to be very hard on oil (shearing - breaking the oil down in 5k miles); there have been quite a few Blackstone Labs UOAs done. For a cheap synthetic, Pennzoil Platinum (PP) has proven to be quite good; standard Mobil 1, not so much. I've converted to PP. That said, Valvoline standard 5W30 has also held up very well. I do my own maintenance; the way I look at it, I know it's done right and I can use synthetic oil and premium filter for about the price of bulk oil and no-name filter at a quick-lube joint.

I buy the PP, Valv Syn, or Mobile 1 with coupons and/or rebates from AZ, WM, or Costco. There is always some coupon/rebate combo being offered if you don't mind a little extra work to save $10-20.

For PP and Valv you can end up with 5 quarts for less than 20 if you fill out the rebate forms. The costco M1 usually ends up around $28-29 for six quarts. I need 7 quarts so I stock up.

I scored five five quart jugs of PP 5W30 from AZ last year after a store manager had marked em down to $16 each. I bought the lot.

I also bought 40 OEM Subie Roki black filters online for $4 each.

Good insurance for long intervals or extreme conditions.

 

[mws4ua]

I suggest the website Bobistheoilguy.com for a TON of information.

I second this recommendation. BobIsTheOilGuy.com has more information than you'll ever want to know about oil.

Specific to this topic, check out "Oil University 103" on that site. (I'd actually recommend reading 101 and 102 first - neither is terribly long.)

 

[subiesailor]

Cheap insurance would be that Lizard insurance company by the way. LOL

Search through the entire forum on engine failure due to oil. Make sure you have plenty of time because your going to be digging and digging and digging to find more than just a few random comments about it.

I laugh how more often than not the people who over do things like say oil changes tend to also be the people who really don't have the extra $$ to be spending it on oil changes. LOL