Synthetic/synthetic blend vs regular oil in 2013 Subaru Legacy 6 cyl

Subaru says use 10-30W synthetic. My local dealer says I can use 10-30W synthetic blend(which is cheaper). Both say the oil should be changed every 7500 miles. Would using regular(non synthetic/synthetic blend) be OK, and if so, would the interval between oil changes have to be reduced?

If your car has a turbo, I would only use pure synthetic. If not the blend would be OK. I would not use regular mineral oil. I would change oil more often than 7500 miles; 5000 miles seems to be best for today’s cars unless you are doing mostly highway driving, which very few of us do.

Don’t try to save money on oil changes; it’s very poor economy! Again, if the car has a turbo use 100% synthetic only. I’m surprised Subaru recommends 10W30 in 2013. Is this in your manual, or is this a Subaru dealer recommendation?. My wife’s Mazda 3, 2012 usues 0W20 synthetic.

Use EXACTLY what Subaru (not the dealer) specifies. If there’s an engine problem you don’t want there to be any question about the oil used.

I don’t think the 6 cylinder Subarus have turbochargers, so regular oil changed at 5,000 miles would work fine, barring any unusual conditions, like -30 degree weather. Check the owner’s manual. It will have the rundown on oil types that should be used. texases advice above is perfect.

All warranty work is cleared through the manufacturer. They are the ones who pay for it, not the dealer. I would use full synthetic as they suggest and feel free to change every 7500 if that is what the manufacturer recommends. It costs more but the change intervals should be longer to recover the difference. If you use a blend or mineral in a pinch and not by choice, I would change at 5000.

Just read new Subaru oil info. ALL new non-turbo subbys use 0-20 syn oil. Turbo motors use 5-30 syn oil.


Subaru changed their oil specification to full synthetic as of the 2012 model year.
As a result, use of either a synthetic blend or a conventional motor oil will allow the mfr to refuse to honor warranty claims on the engine, if it happens to break down.

@VDCdriver Thanks for the heads up. Just what is OP’s Subaru dealer smoking? 10W30 has not ben recommended for 25 years by any manufacturer of passenger cars.

@Docnick–I don’t know what the OP’s Subaru dealer is smoking, but it is probably not something legal. Actually, it is likely that this very poor advice was given by a “service advisor” who has about the same level of automotive knowledge as my dog.

While the oil spec for Subaru changed from conventional to full synthetic in 2012, the viscosity spec has been 5w-30 for…quite a few years.

My guess is that the OP got that information from his dealer’s salesman. Salesmen will say anything to sell a car. And I’ve yet to meet one that knows anything about cars mechanically. The other possibility is that he spoke to the service advisor. VDC has already described my opinion about the technical skills of service advisers. It’s a strictly clerical job, with no requirement to know much about cars. They know as much about cars as a shoe salesman knows about podiatry.

Follow the manufacturer’s recommendations. Use full synthetic. The owner’s manual was written by the manufacturer’s technical writers using specification information provided directly to them as a part of the design documentation. That’s as close to talking to the design engineers as you can get.

The owners manual shows 5W-30 conventional oil for the 6 cylinder and 10W-30 or 10W-40 acceptable for weather zero fahrenheit and above.

Your vehicle is designed to use 5W-30
conventional motor oil, however 5W-30
synthetic may be used for optimum
engine performance.

The 3.6 liter (6cyl.) engine in 2013 says 5w-30 synthetic oil is recommended but not required. ( Subaru’s words ). Oil change interval -regular 7500 miles, Severe usage-3750 miles. Most mfg. consider short trips, cold weather, high speed, or trailer towing as severe service.

After Subaru’s break-in period is over, use ONLY 100% synthetic oil for every oil change and use a good oil filter. My Subaru 95 Legacy had over 340,000 km (210,000 miles) when I sold it, my 86 BMW 325e had over 390,000 km (240,00 miles) when I sold it, both engines were in great shape with compression readings that were still in-spec!

My former boss, a BMW master mechanic and garage owner, told me that before he switched to full synthetic oil in the garage he was doing 2 to 4 engine rebuilds a month, afterwards he went down an engine rebuild every year or two!

Shop around for synthetic oil to save money, but an engine rebuild will cost way more than switching to full synthetic. Also in cold weather full synthetic will flow much better than regular oil so you’ll get the engine lubricated faster when you start the car reducing engine wear. Full synthetic also out performs regular oil at high temperatures as we’ll.

Using regular oil is a false economy, use full synthetic oil and save your motor.

Synthetic oil change = $50 each 7500 miles =$666 over 100,000 miles
Semi-synthetic oil change = $30 each 7500 miles =$400 over 100,000 miles
Rebuilding a coked-up engine = $3500

The math tells the whole story. Like and old commercial, You can pay me now, or you can pay me later!

I just saw a notice from Subaru dealer and it says all new 3.6 motors are spec’d for 0-20 oil. Is a 2012 3.6 spec’d for different viscosity oil? I really don’t think so. But I don’t drive a new Subaru. Folks ask the Subaru service tech and you get different answers. Owners manual says something other than 0-20? I just saw PDF here but it DID NOT list model years. Info looked legit, but anyone can make any document they like. Computers let you do that

In 2013 the 3.6, spec. is 5w-30, synthetic recommended but not required. All 2.5 engines 0w-20 full synthetic is required. I only looked up the 2013 models.