Mobil1 and Blow-by

[OutMax]

I've always used Mobil1 5W-30 full synthetic since I bought my '07 Outback with 5,600 miles on it, and always use Subaru oil filters. I change the oil every 6k because I drive a lot of highway miles.

So I call the local Subaru dealership to ask about the Mobil1 0W-30 and he tells me what I expect to hear: "If you want your warranty to stay valid, use the 5W-30". AND, he goes on to tell me that Subarus are have HORRIBLE blow-by issues when using Mobil1 and he highly recommends I use something else. Ever heard of this?

Also, I have noticed that when I drive at 75-80 mph for a while, I burn through some oil when using Mobil1. Ever experienced this?

I'm going to try Castrol Edge full synthetic for my next oil change at 50k and see what happens.

Also, I saw the poll and it looks like 50% of us use Mobil1.

All comments/thoughts are appreciated!

[szeichdog]

I am still in the break in period on my 2009 Outback but when I hit 3500 miles I am changing to Amsoil 5W30 100% synthetic. I have used Amsoil in all my other vehicles and change the filter every 6 months and do a complete oil change every 12 months or 25,000 miles. Synthetics in general reduce wear and the result is cleaner oil over a longer period of time unless the engine is not sound to begin with. My 1996 Explorer had 161,500 miles on it when I traded it for my new Subie and I changed the oil every 12-14 months or 25,000 miles & the only other maintenance was plugs, wires, and timing belt. Check out www.amsoil.com for more information about viscosities, etc.

Why do you want to change to 0W30? It would perform better at lower temperatures when the engine is cold, but if most of your driving is highway, the operating temperature of the oil will be fairly warm anyway. As far as voiding your warrantee, the dealer would have to prove that the 0W30 oil was the direct cause of any failure.

Also, it has been my experience that if you are getting blowby, it is possible the rings are not seating properly, are worn, or something is out of tolerance. As long as the viscosity index is the same, one oil should display the same flow characteristics as another at normal operating temperature. The advantage of synthetics is that they are slicker than petroleum based oils and tend to create less wear in a sound engine allowing for the extended drain intervals. They also have a lower pour point and therefore lubricate better at lower temperatures than petroleum products. But I have also seen synthetics clean the sludge deposits created by petroleum products around seals resulting in leaks.

[Button]

OutMax,

I currently use Amsoil SSO 0W-30 & both '06 & '08 like to consume/burn between oil change intervals. Nevertheless, I will be trying Amsoil 10W-30 on my next change to see if it helps w/ the consumption.

Regards,
~Button

[neutron]

Any API-labeled oil shouldn't change blow-by characteristics. Blow-by is affected by ring sealing, and as long as there's oil of any weight on the piston, the rings are essentially sealing to their design characteristics. (I don't see any TSBs regarding this matter either.)

[Hooray]

i have heard a lot of hate against mobile 1...blow by, seal degredation etc

i have used it along with other synthetic brands no problem (though i use dino oil in my subie)

many people prefer amsoil and other expensive brands (not that mobil 1 is not)..but i think that some of the preference comes from perceived protection due to the higher price

in the ensuing replies someone can insert all the charts and graphs to show that super expensive oils are better but i will still not be convinced

to each his own

[jnovember]

2007 2.5 non-turbo with 54k. Have used Mobil1 5w30, first changed at 1k, then every 5k with Subaru Filter. Haven't had to ad a drop of oil yet.

[DonRich90]

I bought my '05 OBXT in Dec. '07 with 32,000 miles on the odometer. It now has about 53,000 miles on it. I've used Mobil 1 5W30 and a Subie filter every 3,000 miles since I bouight it and have never had a problem. I've never had to add any oil between changes.

Don

[Petersubaru]

Originally posted by szeichdog
I am still in the break in period on my 2009 Outback but when I hit 3500 miles I am changing to Amsoil 5W30 100% synthetic. I have used Amsoil in all my other vehicles and change the filter every 6 months and do a complete oil change every 12 months or 25,000 miles. Synthetics in general reduce wear and the result is cleaner oil over a longer period of time unless the engine is not sound to begin with. My 1996 Explorer had 161,500 miles on it when I traded it for my new Subie and I changed the oil every 12-14 months or 25,000 miles & the only other maintenance was plugs, wires, and timing belt. Check out www.amsoil.com for more information about viscosities, etc.

Why do you want to change to 0W30? It would perform better at lower temperatures when the engine is cold, but if most of your driving is highway, the operating temperature of the oil will be fairly warm anyway. As far as voiding your warrantee, the dealer would have to prove that the 0W30 oil was the direct cause of any failure.

Also, it has been my experience that if you are getting blowby, it is possible the rings are not seating properly, are worn, or something is out of tolerance. As long as the viscosity index is the same, one oil should display the same flow characteristics as another at normal operating temperature. The advantage of synthetics is that they are slicker than petroleum based oils and tend to create less wear in a sound engine allowing for the extended drain intervals. They also have a lower pour point and therefore lubricate better at lower temperatures than petroleum products. But I have also seen synthetics clean the sludge deposits created by petroleum products around seals resulting in leaks.

Out of curiosity here...how many miles were on the other vehicles before you changed over to synthetics

[Petersubaru]

Originally posted by DonRich90
I bought my '05 OBXT in Dec. '07 with 32,000 miles on the odometer. It now has about 53,000 miles on it. I've used Mobil 1 5W30 and a Subie filter every 3,000 miles since I bouight it and have never had a problem. I've never had to add any oil between changes.

Don

5/30 dino or syn ??

[fuel98rider]

I have used Mobil 1 5w-30 since the first oil change at 3,000 miles. After 27,000 miles, I do not get oil blow-by or oil consumption. I put 4 quarts in, and I get enough out to come within a 1/4" of the top of a gallon milk container. That beats any GM product I have ever owned.

I don't know whether Mobil 1 is truly better than anything else for my Subaru. I usually do not let price be a deciding factor on most decisions about my car. I do know that I spend zero time worrying about my oil with Mobil 1 in the car.