switching oil weight

[all-trubo [STi]]

well im at 50k on my sti, and it was suggested to me by a few folks to run a heavier weighted oil. maybe bumping up to a 10w-30 or 15w-50 or so. its time for me to change my oil, and im just wondering if i should or shouldnt do it. will a thicker oil not be consumed by the 2.5 or maybe not as much as the 5w-30?? i am curious.

btw, i did search for this topic and all i found were topics about the sti eating oil (which mine does as well) and people toasting their motors for not having/adding oil because of the consumption.

[Unabomber]

Please post in the right forum.

There are many experts on different facets of Subaru information. They tend to view and respond in the forums where their knowledge level is highest. By posting in the inappropriate forum, you are not only diluting the wrong forum, but short changing the search results of others and increasing the chances of an expert missing your question.

[scoobdude]

please check out www.bobistheoilguy.com this is pure oil and lube info

[vvk]

Yes, given reports of increased oil consumption from others, I would recommend using something slightly more robust than low-HTHS 5W-30. If you'd like to stay with recommended viscosity for warranty retention, try using a 5W-30 oil with HTHS above 3.5. BMW 5W-30 comes to mind -- inexpensive and readily available at your friendly local BMW dealer.

An API-rated "high mileage" oil would do nicely, too. But look for one that has the right viscosity. For example, Valvoline MaxLife is NOT the one to use. Castrol GTX HM 5W-30 and Pennzoil HM 5W-30 both have slightly higher HTHS viscosity. Look for 5W-30 oil that does NOT indicate "Energy Conserving" on its label.

If warranty is not a concern, I would use German Castrol Syntec 0W-30, if you can find it. Or a more commonly available 10W-40 oil, such as new Mobil 1 EP 10W-40, Castrol Syntec 10W-40 or Valvoline Durablend 10W-40. For low-temperature environments use 5W-40, such as Valvoline SynPower 5W-40 available at PepBoys.

[dsc]

Use whatever weight the manual says to use. If the manual says 5W-30 it's because the clearances in the motor are designed for that viscosity. Using a heavier oil will result in reduced oil flow. Why would you want that?

Also, why is the motor using oil after only 50K miles? Is it a leak issue or a oil burning issue?

[bluesubie]

Originally Posted by dsc

Use whatever weight the manual says to use.

The manual lists many weights. 5W30 is "preferred" for better fuel economy, but 10W30 and 10W40 are probably listed on the temp. chart for higher temps. It also probably says that oil of a higher viscosity is required to properly lubricate the engine in high temps.

I would not use less than a 10W30 in So. Cal.

-Dennis

[all-trubo [STi]]

Originally Posted by dsc

Use whatever weight the manual says to use. If the manual says 5W-30 it's because the clearances in the motor are designed for that viscosity. Using a heavier oil will result in reduced oil flow. Why would you want that?

Also, why is the motor using oil after only 50K miles? Is it a leak issue or a oil burning issue?

im positive its not a leak, its just consuming it. it was very minimal but now its about 1qt every 1k miles.

[dsc]

Originally Posted by all-trubo [STi]

im positive its not a leak, its just consuming it. it was very minimal but now its about 1qt every 1k miles.

Bummer. Is that a common problem with STi motors?

Just curious - Are you using synthetic oil? I know that synthetics are more prone to leak, but I've not heard that they are any more likely to get consumed by the engine.

[poison]

Originally Posted by dsc

Use whatever weight the manual says to use. If the manual says 5W-30 it's because the clearances in the motor are designed for that viscosity. Using a heavier oil will result in reduced oil flow. Why would you want that?

Also, why is the motor using oil after only 50K miles? Is it a leak issue or a oil burning issue?

Bull****. They say 5/30 to meet CAFE requirements. If the 'tolerances were designed for a 5/30', then why the **** do Brits run 15/50 in the same car no problem?



i love oil old wives tales: "My granpappy said..."

[dsc]

Originally Posted by poison

Bull****. They say 5/30 to meet CAFE requirements. If the 'tolerances were designed for a 5/30', then why the **** do Brits run 15/50 in the same car no problem?

i love oil old wives tales: "My granpappy said..."

Well, poison clearly knows his oil. Otherwise, he wouldn't be cussing about it. I mean, if I've got someone cussing at me about oil, you better believe I'm going with him over the manufacturer's recommendations every time.

All kidding aside, I think that it might be true that Subaru recommends 5w30 to help its CAFE numbers. That is why I use 10w30 in the Impreza. The book says either is OK.

poison, are you saying that 15w50 is a good weight to use in an Impreza? If so, why wouldn't 80w90 be even better?

[stripperluva]

My '04 burns 1 quart every 1500 miles right now and the subie dealer says 1 qrt per 1000 miles is acceptable.

........I am thinking bullsh**

[Hayes]

I think 1000 miles per quart is BS too. That is the number General Motores told their dealers to say when that had big oil consumption problems in the 50s and 60s. eddie

[Uncle Scotty]

10w30 is the lightest I'd run...especially M1....the 5w30 M1 is like water....

The truck/suv 5w40 is the next change fro me.

[poison]

MMMMM, 5/40 t&s, good stuff, maybe the best. That will be my next change after I use my stash of 10 German Castrol 0/30.

[WRXout]

i use syntec 10w-30 on my sti, no oil consumption :knock on wood: 10995 miels

[subenerd]

Ive been using redline 5w30 for about 34k miles and have been thinking of moving to 10w30. Car runs good, doesnt burn barely anything unless Im very hard on it. The engine seems loud, maybe I could use thicker oil, I dunno...oil specs make my head spin

[bluesubie]

Originally Posted by subenerd

Ive been using redline 5w30 for about 34k miles and have been thinking of moving to 10w30. Car runs good, doesnt burn barely anything unless Im very hard on it. The engine seems loud, maybe I could use thicker oil, I dunno...oil specs make my head spin

Redline 5W30 is thickAr than M1 10W30 at 100C, and has a higher high temp high shear viscosity as well. Must be those polyol ester base stocks.

My head is spinning too.

-Dennis

[Silver04WRX]

Originally Posted by bluesubie

Redline 5W30 is thickAr than M1 10W30 at 100C, and has a higher high temp high shear viscosity as well. Must be those polyol ester base stocks.

My head is spinning too.

-Dennis

Yeah...when I was looking into oils, I noticed that Mobil1 10W30 was somewhere in between Redline 5W30 and 10W30. I guess you can't always go directly off weights...I'm definitely gonna try M1 10W30 next oil change. It doesn't seem like a huge jump from M1 5W30....which is thin already.

[subenerd]

would 10w make the engine a bit quieter?

[poison]

I apologise for my show of passion over oil.

15-50 would probably run ok in a hot climate, but with reduced gas mileage. Of course 80-90 would choke it, or kill it with the lack of start up protection. But I am pretty sure that the only place Subaru specs a 5/30 for pretty much all temps is in the US and that is because of CAFE. Elsewhere they spec the oils best for the engine.

By the way, the Mobil 1 T&S is rumored to be the same as or similar to the Mobil Delvac 1, a fully synthetic diesel/gas mixed fleet heavy duty engine oil. Pretty much the holy grail for outstanding protection and long OCI's.

vvk, who is on BITOG, here also, I think, has a 2.5L and has run a lot of different oils, with Redline 5/40 producing the best oil analysis. A lot of Suby owners seem to get good results with Redline.

[dsc]

Originally Posted by poison

I apologise for my show of passion over oil.

No sweat.

15-50 would probably run ok in a hot climate, but with reduced gas mileage. Of course 80-90 would choke it, or kill it with the lack of start up protection. But I am pretty sure that the only place Subaru specs a 5/30 for pretty much all temps is in the US and that is because of CAFE. Elsewhere they spec the oils best for the engine.

Sounds reasonable. The point I was trying to make is that I don't have the resources to do the testing needed to know which oil to use, so I have a hard time departing from the manufacturer's recommendations. Sometimes the manufacturer's recommendations don't make a lot of sense. I think the book that came with my 1997 Impreza said to use 5W-30 for all temperatures, but permitted 10W-30 so long as the temperature does not exceed 90 F, or something like that. That recommendation makes no sense to me because 5W-30 and 10W-30 are supposed to act the same way at high temps. The difference between those oils is at low temps. Isn't it? I think that book is probably a good example of the recommendation being driven by CAFE rather than what's best for the motor.

I just bought a 1998 Honda Accord for the wife. It has the 2.3 litre VTEC 4-cylinder. What a sweet running motor. The book recommends 5W-30 "Energy Conserving" oil. It also says, "You may use a 10W-30 oil if the temperature in your area never goes below 20 degrees F (-7 C)." Now, what in the heck do I do with that information? I am inclined to use 5W-30 from November through March and 10W-30 the rest of the time. See any problem with doing that? I will probably use Mobil 1 because it is readily available, but I might use Amsoil.

[bluesubie]

Originally Posted by dsc

That recommendation makes no sense to me because 5W-30 and 10W-30 are supposed to act the same way at high temps. The difference between those oils is at low temps. Isn't it?

The SAE has a range for each oil viscosity. This Advance Auto Parts site has good info.

"SAE 30 is SAE 30 no matter what the "W" prefix number is: 0W, 5W or 10W. This viscosity in centistokes (cSt) @ 100 degrees C is with the minimum of 9.3 cSt and a maximum of 12.5 cSt."

You can have two 5W30's with the thickness of one on the lower end of the range and the other on the higher end. Generally speaking, the one on the higher end will probably give you more protection. For example, M1 10W30 is 10.0 Cst @ 100C and German Syntec 0W30 is around 12.3 (IIRC). You're probably going to get better protection from the Syntec (then there's additives, base stocks, etc.).

You would think that all 30 weights would be the same, but that's not the case.

-Dennis

[Silver04WRX]

Originally Posted by bluesubie

The SAE has a range for each oil viscosity. This Advance Auto Parts site has good info.

"SAE 30 is SAE 30 no matter what the "W" prefix number is: 0W, 5W or 10W. This viscosity in centistokes (cSt) @ 100 degrees C is with the minimum of 9.3 cSt and a maximum of 12.5 cSt."

You can have two 5W30's with the thickness of one on the lower end of the range and the other on the higher end. Generally speaking, the one on the higher end will probably give you more protection. For example, M1 10W30 is 10.0 Cst @ 100C and German Syntec 0W30 is around 12.3 (IIRC). You're probably going to get better protection from the Syntec (then there's additives, base stocks, etc.).

You would think that all 30 weights would be the same, but that's not the case.

-Dennis

Is it bad to have too many additives? I've been looking into Mobil 1 Extended Performance. They said they increased the amount of syper syn and other stuff over the regular Mobil 1 synthetic. They claim it will hold up for at least 15,000 miles or 1 year.

[poison]

I just saw those Extended performance oils at Kragens. I'll have to check into those. Interesting. There is a 7500 and a 15000 version.

[Uncle Scotty]

I just bought a jug of the 10w30 EP15000 M1 at wallyworld, by mistake....it was for someone else, I wanna run the 5w40 SUV/truck....it cost $23.xx rather than $19.88 for the regular M1.....