Synthetic oil change interval

I took my car in to get a cracked windshield replaced and asked for them to do an oil change as well. The subaru dealer told me they'd do it if I wanted, but that I was wasting my money. The service guy went on to say that I only needed to change my oil every 7500-10000 miles. I am running synthetic, but i've never heard of such long intervals between oil changes.

 

Should I really only get my oil changed every 10000 miles or so? I have a hard time believing that guy honestly.

Amsoil actually states that for turbo'd or supercharged engines to follow the manufacturers rec'd intervals. On reg engines it is MUCH longer.

Have used synthetic since 3k miles......always change every 4-4500 miles. Yea....it's early but well worth it in the long run:)

On my Honday CRV, I'll do oil change (Mobil 5W20) every 10k and oil filter every 5k. As for my LGT, I'll change it every 4k. I don't think I'll push it that much with a turbo engine.

I use synthetic, and if you drive the car even a little bit aggressive I would change oil every 4K maybe even sooner, it looks fairly beat after just 2K.

i do between 4 and 5K with mobil 1 syn.

 

it's okay to extend it a little bit, and the companies are right that oil is effective much longer than the old world dino oil. but they neglect to tell you the weak link in the chain is still the filter. 4-5K is okay on a filter, but after that, it's just not cleaning optimally.

 

dR

Depends on your driving conditions, engine, weather, etc....

 

The only true way to know, is to perform a UOA(used oil analysis). I have done these a few times, and from my experience in my conditions, I can easily run 7k between changes. In fact I was advised to increase to 8k, and recheck to see if I can go any further. My conditions are 75/25 in favor of highway, and I have a daily commute of about 88 miles. This gives plenty of time for the oil to reach operating temps, and burn off any condensation, and raw fuel vapors that get past the rings. So you can say, that my engine is run under almost ideal conditions.

 

Changing your oil more often wastes $$$ and time. For $30, you can pretty much peg down exactly how often your engine needs an oil change for your specific conditions, AND you also get to see what your engine's condition is. The UOA gives a detailed analysis on as well as giving you some warning of impending failures like:

 

And once you know your OCI(oil change interval), then you can drop the testing of the remaining active additives, which reduces the price of the UOA to $20. You should go and checkout BITOG, they are very passionate & knowledgeable about all Oil.

I second the UOA. I had Blackstone do the full boat test and my TBN (total base number) was 3.8. I has run 6,089 winter miles on Castrol Syntec 0W/30. My driving would qualify as severe as my daily commute is 2.6 miles (4x per day), but it does get regular weekend trips (hence 15k in a year). Blackstone indicated that a TBN of 3.8 meant there was still active additive remaining and that the oil could be run longer.

 

I'm going to try 7500mi this time and see where it falls. It looks like you can easily double the mileage with a good synthetic (Castrol 0W/30 is one of the best). that would make severe duty changes at 7500mi and normal changes at 15k (would probably change the oil filter at 7500). YMMV

running mob1 since 3k and change every 3kmi.

I second the UOA. I had Blackstone do the full boat test and my TBN (total base number) was 3.8. I has run 6,089 winter miles on Castrol Syntec 0W/30. My driving would qualify as severe as my daily commute is 2.6 miles (4x per day), but it does get regular weekend trips (hence 15k in a year). Blackstone indicated that a TBN of 3.8 meant there was still active additive remaining and that the oil could be run longer.

 

I'm going to try 7500mi this time and see where it falls. It looks like you can easily double the mileage with a good synthetic (Castrol 0W/30 is one of the best). that would make severe duty changes at 7500mi and normal changes at 15k (would probably change the oil filter at 7500). YMMV

 

Definitely agree on the Castrol 0W/30 which can be found at Auto Zone, its made in Germany and is totally different than the other Castrol Syntec stuff.

 

For me, if I can't extend the drain interval synthetic isn't woth the extra expense. Use a good quality filter such as the Sub OEM black filters and your good to go. Subaru's are generally easy on oil so a good quality dino oil would be fine unless you run extended periods in boost.

I change my synth every 3k miles. no excuses.

I switch to synthetics beginning at ~5,000 miles, then change it every ~5,000 miles (10K, 15K, 20K, 25K, etc.) to make it easy to remember.

 

-Mike-

http://www.legacygt.com/forums/showthread.php?t=28397

 

Thank you blah blah blah.....

 

Yes, you can use synthetic oil in your Subaru. If you do use synthetic oil, we would recommend that you always use it in your engine because your engine will become accostomned to it. The same goes if you decide to use 'regular' oil.

 

Synthetic oils can be used in our engines if the user follows the engine oil recommendations prescribed in the owner's manual. Subaru has not tested the compatibility of all syntthetic oils with engine seals, but the petroleum industry does adhere to standards for refining process which meet Subaru requirements. Subaru does not guarantee the performance of any brand of engine oil.

 

Engine oil guidelines: - only use engine oil that meets or exceeds API classification designated in the Owner's Manual for the vehicle. - only use engine oil that meets the VISCOSITY requirements for the ambient temperatures under which the vehicle will be operated as outlined in the Owner's Manual - THE ENGINE OIL MUST BE CHANGED AT INTERVALS SPECIFIED IN THE WARRANTY AND MAINTENANCE BOOKLET FOR THE VEHICLE. SOME SYNTHETIC OIL REFINERS RECOMMEND EXTENDED OIL CHANGE INTERVALS SUBARU DOES NOT RECOMMEND DEVIATION FROM THE SPECIFIED INTERVALS IN THE OWNER'S MANUAL.

 

Thank you blah blah blah...

 

John J. Mergan

Subaru of America Inc.

 

We do oil analysis on most of our cars. When I last checked the 97 Subaru OBW we had (at 140K miles) the oil was showing no signs of wearing out at 7,500 miles. On that vehicle we used Castrol.

 

I asked the analyst at the oil analysis place (http://www.natrib.com) what the primary benefit of changing oil at 3,000 miles was. He daid, "You create very high quality waste oil."

 

I asked the analyst at the oil analysis place (www.natrib.com) what the primary benefit of changing oil at 3,000 miles was. He daid, "You create very high quality waste oil."

 

+1, I see no reason to change oil at 3k, esp. synth. Evidence seems to suggest 3k oil changes are a waste of $, at least for synth. But I'm not going to tell others how to spend their $, for some, it's peace of mind.

Mobil1 5W-30 every 5K here...

Regular Oil about every 4500-5000 miles for me. Not switching over to Synethic till 20k mi.+

Another German Castrol 0w30 user here. I have done a couple UOA's and while Blackstone suggests that I could go longer, I have been going 5000 miles between changes. On my wife's Mazda6, running a blend of M1 0w20 and 10w30 I run 7500 miles between changes. Her car sees almost 100% highway miles and the wear is less than most others experience in half the mileage. Since the Mazda is now out of warranty, I might extend the changes out to 10k miles. While I'm pretty sure that I don't have much of a powertrain warranty left in my LGT (mods) I will still stay at or under the factory recommended 7500 mile interval. If nothing else it just makes me feel better. Anyone running 3000 mile intervals on synthetic is just throwing their money away.

I had always been under the impression that when your oil turns black it's no longer good. However, recent reading has shown that it's the suspended contaminates responsible for the blackness of your oil.

 

Most people should follow the severe maintenance schedule. Synthetic or not, 3,750.

 

Quote from SOA:

 

THE ENGINE OIL MUST BE CHANGED AT THE INTERVALS SPECIFIED IN THE WARRANTY AND MAINTENANCE BOOKLET FOR THE VEHICLE. SOME SYNTHETIC OIL REFINERS RECOMMEND EXTENDED OIL CHANGE INTERVALS. SUBARU DOES NOT RECOMMEND ANY DEVIATION FROM THE SPECIFIED INTERVALS IN THE OWNER'S MANUAL.

I had always been under the impression that when your oil turns black it's no longer good. However, recent reading has shown that it's the suspended contaminates responsible for the blackness of your oil.

 

Most people should follow the severe maintenance schedule. Synthetic or not, 3,750.

 

Quote from SOA:

 

THE ENGINE OIL MUST BE CHANGED AT THE INTERVALS SPECIFIED IN THE WARRANTY AND MAINTENANCE BOOKLET FOR THE VEHICLE. SOME SYNTHETIC OIL REFINERS RECOMMEND EXTENDED OIL CHANGE INTERVALS. SUBARU DOES NOT RECOMMEND ANY DEVIATION FROM THE SPECIFIED INTERVALS IN THE OWNER'S MANUAL.

 

Nice thing about synth, you can take it out and use it in your truck or tractor :^)

Mobile 1, every 5 to 6K, and have done so in every car I've owned since '85. When I first started using it, I'd only replace the filter evey 5K, and full oil change at 15K. Kinda' made me paranoid doing that, so I went the "traditional" factory reccommended way. Changing oil every 3K miles is just a faster way for oil companies to get into your wallet. FYI, when I changed out the timing belt for my second time in my old '92 Subee LegWgn (180K miles), you should have seen the inside of the head cover, cams, etc... Looked like it just came off the frik'n factory floor. Mechanic went into shock, and now advocates its use to every one of his clients.

The only way I can justify using synthetic is to do 7500 mile oil changes from a fincial perspective. 5 Qts mobile 1 + Oil Change at dealer = 2x non-synthetic oil changes at the dealer. So if I change the oil with dino every 3750 it costs the same as if I do a synth change every 7500 miles. It saves me time which is more important to me then $$$'s. Plus I know that synth is hardly tired at 7500 miles and it gives me the piece of mind of knowing I'm using the best lubricant I can for my engine. After the warrenty expires I'll probably consider 10,000-12,000 mile oil change intervals depending on what an oil analysis shows. BMW regularly takes 325i's to 12-15K on synth. I've seen pleanty of research that shows that synth is capable for 12-15K changes however the filter may need replacing in less then 15K miles. BTW black oil does not indicate the oil is worn out.

I would never change synthetic like Mobil 1, German Castrol Syntec 0W-30, or Redline at such short oil change intervals.

 

7000 miles, up to 10000 miles, is a safe and normal interval on a modern engine....as long as you use a good filter.

 

I suppose if we were talking bumper to bumper short trip, track time or dusty off road then a shorter interval should be reconsidered.

Doesn't this interval void warranty on engine?

 

I would never change synthetic like Mobil 1, German Castrol Syntec 0W-30, or Redline at such short oil change intervals.

 

7000 miles, up to 10000 miles, is a safe and normal interval on a modern engine....as long as you use a good filter.

 

I suppose if we were talking bumper to bumper short trip, track time or dusty off road then a shorter interval should be reconsidered.

Doesn't this interval void warranty on engine?

 

According to SOA, you may use synthetic oil but you must follow the maintenance schedule. They also go on to say that "most" people should follow the "severe" maintenance, that the normal schedule is for optimal conditions.

Subaru should get into the 21st century with their oil change interval information.

 

Not everyone should follow the "severe service" intervals. Using this interval is good if you sit in stop & go traffic all day, if you drive your car short distances frequently (so the oil never has time to heat up), or if you drive in dusty/dirty conditions.

 

Something like a 70/30 highway/city daily commute is not considered "severe."

 

Intervals should be different based on how one drives their car. Redline the motor a lot? Road racing? Change it more frequently. Lots of highway miles? Change it less frequently.

 

Despite the warranty information, oil analysis will tell you how your oil and motor are doing better than some generic owner's manual that has a blanket statement to cover their ass for all car models.

 

Now that I think of it... Is the oil change interval written in the manual the same for all Subaru models? If it is, then it's bunk. My $0.02.