Went with Mobil 1 5W-30 in a 2004 WRX

[y_p_w]

I've pretty much only used the standard M1 5W-30 (experimented with the 0W-40 for about 6K miles once) since I ended breaking in my engine at 6000 miles with Mobil Drive Clean 10W-30.

I was thinking of getting the 5W-30 EP, but then saw the higher price and checked the discussions hinting that the 5W-30 HM has a better additive pack and is likely a superior protecting oil.

Now I supposed I'm going to use it for my next oil change, but I'm wondering if there will be any perceptible change in fuel economy. I didn't really notice much happening when I used 0W-40, but then again I went up in the Sierra on vacation and a whole lot of variables crept in. My miles are now about 95% freeway because of a long commute, and I've gone as much as the 7500 mile recommended change interval in my owner's manual. I know they changed it to a recommended 3750 under all conditions, but I'm not sure it's an issue with my regular 50 mile commutes.

 

[Bandito440]

Oh no. the Subaru Mobil 1 haters are going to jump all over you.

The MPG difference between 30 and 40-weights is going to be unnoticeable. Most people recommend 0w-40 or 5w-40 in those turbo Subarus, although I saw a great UOA recently with PU 5w-30.

I'd probably forego the M1 5w-30 in favor of any of Castrol 0w-30, M1 0w-40, or Rotella T6, which I am especially fond of.

 

[y_p_w]

I did see M1 0W-40 and M1 Diesel Truck 5W-40 at exactly the same price.

 

[gathermewool]

Originally Posted By: Bandito440
Oh no. the Subaru Mobil 1 haters are going to jump all over you.

The MPG difference between 30 and 40-weights is going to be unnoticeable. Most people recommend 0w-40 or 5w-40 in those turbo Subarus, although I saw a great UOA recently with PU 5w-30.

I'd probably forego the M1 5w-30 in favor of any of Castrol 0w-30, M1 0w-40, or Rotella T6, which I am especially fond of.


Some turbo Subie guys are against the plain-Jane M1, not the HM or 0W-40 varients. Others, however have heard, "something, something, M1 will kill assplode your engine!" And refuse to use any M1 product, which is foolish.

Personally, I wouldn't ever use regular M1 in my STI, but only because there are better options out there for this application, such as those listed above.

 

[The Critic]

If an oil meets the OEM requirements for the application, then it is safe for the application. Not sure what the big deal is.

 

[buster]

^ +1.

The Subaru M1 issue is not an oil related problem. It's simply due to the fact that Mobil 1 is by far the most commonly used synthetic on the market.

 

[SwampSurvivor]

Yeah M1 has a bad reputation with the subaru crowd.

I had a friend who ran dino 20w-40 and claimed it was better than M1 for the subaru.

I'm not familiar so I don't know.

 

[buster]

LOL

 

[y_p_w]

Originally Posted By: buster
The Subaru M1 issue is not an oil related problem. It's simply due to the fact that Mobil 1 is by far the most commonly used synthetic on the market.

Zero issues so far over 100K miles. Rarely more than 1/2 quart topped off on oil even up to . However, once I did add about a quart and an experienced Subaru mechanic (does work on the side at home) told me that sometimes on hard cornering that boxers have a tendency to lose oil through the PCV valve.

 

[y_p_w]

Originally Posted By: Miller88
Yeah M1 has a bad reputation with the subaru crowd.

I had a friend who ran dino 20w-40 and claimed it was better than M1 for the subaru.

I'm not familiar so I don't know.

I don't even know where to find it. I remember years ago my dad leased a MB 300D turbo. I read the approved oils list, and it included a lot of European brands that we couldn't find in the US (like Duckhams) as well as a lot of 20W-40 oils. I remember seeing a change sticker from the dealer that said they used QS 20W-40. Not sure where you can find anything like that in the US.

My first car was an '89 Integra RS. If you brought it in to that dealer for servicing, they only used Castrol GTX 20W-50. When changing the oil elsewhere, it was almost always some 10W-30. Heck - I remember back in the late 80s when 5W-30 was hard to come by.

 

[kschachn]

So why are you posting on this thread then?

Originally Posted By: Miller88
Yeah M1 has a bad reputation with the subaru crowd.

I had a friend who ran dino 20w-40 and claimed it was better than M1 for the subaru.

I'm not familiar so I don't know.

 

[MBS500]

If it's stock, you don't track it and manual says use 5w-30, there should be no problem.

 

[Errtt]

Co worker decided to try M1 & now says he doesn't like it. I asked why and his best answer was its too expensive and he's going back to PYB again. Well alrighty then I said.

 

[y_p_w]

Originally Posted By: MBS500
If it's stock, you don't track it and manual says use 5w-30, there should be no problem.

It's stock except for a Mishimoto 2-row Al radiator that replaced the cracked factory Calsonic. Doubt that makes a difference with the engine.

The manual says all sorts of stuff. I've understood that they all came from the factory with some sort of 5W-40 oil, but I didn't see that mentioned in the manual. The standard recommendatiion is for an ILSAC starburst 5W-30. The original filler cap said SJ, but I replaced the old cap when the gasket fell off, and the replacement just has the starburst and 5W-30. The manual actually recommended just 5W-30, 10W-30, or 10W-40 for normal driving. They had a list of optional weights for severe stuff like continued high temps or towing - 30, 40, 20W-40, or 20W-50.

I remember hearing a recommendation that the ideal for many engines would just be 30 wt and using a block heater so there wouldn't be cold starts. I don't think it would be as fuel efficient as modern multigrades, but it would probably work well. Of course there would be the issue of where to plug it in on the road, but it was really a theoretical answer.

 

[05LGTLtd]

Originally Posted By: Bandito440
Oh no. the Subaru Mobil 1 haters are going to jump all over you....

I'd probably forego the M1 5w-30 in favor of any of Castrol 0w-30, M1 0w-40, or Rotella T6, which I am especially fond of.


I'd add castrol 0w40 to that list. I've had good results with PU 10w30 as well. M1 5w-30 might be fine, but I'd run a upa at 4k to be sure. Pushing these engines to 7500 mile drains is questionable. Some do fine some not. 4-5k is more reasonable. Enjoy the Rex!

 

[bluesubie]

There are still failures happening on regular M1 5W-30 (and other RC 5W-30's) so people aren't making this stuff up. Mobil1 being no good for Subaru's is a fight that I've been fighting for a long time. I try to educate people that it's a viscosity issue for certain driving conditions (plus a nut behind the wheel issue).

Ignoring the SoA recommended (SoA recommended because very few countries recommend Resource Conserving oil in a Subaru turbo) oci for your model year is not a good idea IMO. I did it twice and had a turbo failure. Read this Subaru Drive article if you're not familiar with it.

http://drive2.subaru.com/Sum08/Sum08_Turbo.htm

When I contacted Mobil1 for a recommendation mentioning my driving conditions and the owner's manual recommendations that you mention above, they advised to use 0W-40. That was even before my AcessPort reflash. I would contact them if I were you.

Sure you MIGHT be ok with 7,500 mile intervals on EP or HM, but I would stick with 0W-40 if you go beyond the recommended oci regardless of how any uoa looks or the oil marketing. Even then I would be cautious about pushing it past 6k, but your highway mileage might be fine.

I do believe the 2.0 is easier on oil than the 2.5 though and my friend's abused 2003 2.0 is still going strong and he uses whatever oil is on sale and couldn't tell you his oci's if his life depended on it.

Good luck!

-Dennis

 

[y_p_w]

Not sure what to do if I get a new WRX or maybe even the STI - with the 0W-20 recs. Would there be an alternate rec for those willing to sacrifice fuel economy?

 

[cutlassvillager]

My father's 02 WRX has had various 5w-30 synthetics (including many intervals of M1) from new to now 155k miles. No problems and still has the stock turbo. He's not exactly easy on it either. It does consume a little oil (1qt every 5,000 miles) and consumption has seemed to be the lowest I can remember this last oil change using 5w-30 QSUD. M1 0W-40 has also been used along with BMW 5W-30 (on the thicker side of a 30wt).

 

[bluesubie]

Originally Posted By: y_p_w
Not sure what to do if I get a new WRX or maybe even the STI - with the 0W-20 recs. Would there be an alternate rec for those willing to sacrifice fuel economy?

The new turbos still spec 5W-30 (n/a's spec 0W-20) but the temp chart with the thicker viscosities is gone. There is goofy language saying that 5W-40 conventional (which doesn't exist) or 10W-40 conventional may be used for replenishment only and must be switched to "full synthetic" at the next oil change.

Of course, they don't talk about the MSDS language for the Idemitsu Subaru oil that states:
"The petroleum base oils contained in this product have been highly refined by a variety of processes including solvent extraction, hydrotreating, and dewaxing to remove aromatics and improve performance characteristics."

Ok, I suppose the default marketing "definition" of this is "full synthetic".

Owners of new models are still running all sorts of things. Subaru 5W-30, Pennzoil Ultra 5W-30 (great NOACK numbers), Euro 5W-30's that meet ACEA A3 and API SM specs, and some are still running RT6 and Mobil1 0W-40. There are actually a few dealers that agree to put in 5W-40. Some are mixing 5W-30 and 5W-40.

-Dennis