Oil Change

[RLsChMiDt]

I know this has been discussed, but do you recommend 5W-30 or 10W-30? If either, which is better for summer, and which for winter?

P.S.: I did my first oil change this weekend (by myself)...lol at 4900...first one was at 1700 by Lubestop

[SD_GR]

A 5W-30 will generally provide marginally better fuel economy than a 10W-30, and certainly better cold startup protection than a 10W-30 in climates with a heavy winter. There are exceptions, where manufacturers post very close specs for their 2 oil grades. Many 5W-30s and 10W-30s from the same maker are chemically quite close, differing in the additive package and/or maybe the viscosity index improvers.

If you have a severe winter, you might want to use 5W-30 for the colder months and switch to 10W-30 for the wamer months. or just use 5W-30 year round. I don't deal with a winter worth speaking of, and I do have rather warm operating conditions in my area. 5W-30 is a broader "spread" than 10W-30, and my suspicion is that the 10W grade of the same oil - M1 in my case - will stay in grade longer and hold up better, longer than a 5W. This is at the expense of an MPG or so perhaps, but oh, well. I see no need to use a 5W in my area other than to "satisfy" CAFE standards, so I'm going 10W-30, which is still a listed grade and apropriate according to the temp charts in the manual. Your area may vary so check the chart for the grade(s) you can use.

If you do your own oil changes, keep your dated receipts so you can document them to a dealer in the future - may you never, ever need to though.

[KurleeDaddeeWRX]

Here is some great info I found on engine oil:

Viscosity
Viscosity (a fluid's resistance to flow) is rated at 0° F (represented by the number preceding the "W" [for Winter]) and at 212° F (represented by the second number in the viscosity designation). So 10W-30 oil has less viscosity when cold and hot than does 20W-50. Motor oil thins as it heats and thickens as it cools. So, with the right additives to help it resist thinning too much, an oil can be rated for one viscosity when cold, another when hot. The more resistant it is to thinning, the higher the second number (10W-40 versus 10W-30, for example) and that's good. Within reason, thicker oil generally seals better and maintains a better film of lubrication between moving parts.

At the low-temperature end, oil has to be resistant to thickening so that it flows more easily to all the moving parts in your engine. Also, if the oil is too thick the engine requires more energy to turn the crankshaft, which is partly submerged in a bath of oil. Excessive thickness can make it harder to start the engine, which reduces fuel economy. A 5W oil is typically what's recommended for winter use. However, synthetic oils can be formulated to flow even more easily when cold, so they are able to pass tests that meet the 0W rating.

Once the engine is running, the oil heats up. The second number in the viscosity rating--the "40" in 10W-40, for example--tells you that the oil will stay thicker at high temperatures than one with a lower second number--the "30" in 10W-30, for example. What's really important is that you use the oil viscosity your car's owner's manual recommends.



Quoted from this link: http://popularmechanics.com/automoti...l/index3.phtml

[wrxdude]

I changed my oil to synthetic at about 6000mi. I went ahead and used M1 0W-40. I couldn't see any harm in using it (it is factory fill for all porches and Mercedes) although I wasn't aware that the manual did not say it was an acceptable weight. Is there any reason why we shouldn't use a 0W-40 synthetic oil in our wrx's? I have a hard time imaginig a reason why we couldn't use this oil in our cars, as long as we monitor the oil level and keep it topped off. Thanks.

[SD_GR]

Originally posted by wrxdude
Is there any reason why we shouldn't use a 0W-40 synthetic oil in our wrx's? ... Thanks.

None at all. Actually, there's compelling reasons to *use* M1 0W-40. It is their flagship gasoline engine oil in the USA. It meets ACEA A3-02 and Merc's MB229.3; both are very stringent specs (whereas API SL is laughable in comparison). I can only think of a very select group of oils commonly available in the USA that meet these specs and are therefore engineered to such high standards (and M1 15W-50 is one of them).

I assume M1 0W-40 is not derived from the same basic formulation as their xW-30 series (these oils are still quite good, probably the best on the shelves in most stores right now, meeting ACEA A5).

The only reason I don't use M1 0W-40 is the warranty requirement. The book specs 5W- or 10W-30, 10W-40, 10W-50, 20W-50. Not 0W-40 and not 15W-50, so no Mobil1 ACEA A3 oils! Sad, silly, but true.

SD

[tan]

If you want to know the appropiate oil change intervals, spend about $20 to get an oil analysis done. It tells you the state of the oil and the engine, and based on the analysis, recommend the change interval.

Very important!!!You can't judge the oil condition by its color. Oils made in different batches can have differences in color from batch to batch.

Take my diesel engine for instance, after I change the oil and run the car for a minute, it is instant black (from the soot). But the oil is still good.

[wrxdude]

SD_GR, thanks for the very informative reply. I was wondering why I haven't seen a lot of people using the M1 0W-40. I figure I'll just keep on using it. It seems like the ideal oil, especially here in S. Cal where it will get hot in the summer. I'm not too concerned about the warranty issue. I find it hard to believe that at some point I will be denied a warrantied repair because of the oil I used. And I'm figuring on buying an extended warranty through my insurrance company anyway. Much cheaper than the factory extended warranty and there won't be the concerns about getting denied warrantied repairs because of modifications to the car.

Thanks!

[Jeffsw_02WRX]

For the first time, I’m doing my own oil change on my WRX this weekend. I’ve lived in Apartment complexes and have never had a good way to change oil myself, so have always paid shops to do it. I have a few questions about changing the oil, and switching to synthetic…

Is this the correct procedure for changing oil?:
1. place oil pan under car
2. open drain valve and drain all oil into pan
3. Remove and replace oil filter
4. Close drain valve
5. Fill engine up with correct amount of oil

Also, I would like to switch to Mobil 1 10W-30 synthetic. Do I have to do anything special in my transition oil change from conventional to synthetic oil like flush some extra oil through after draining?

What brand Oil Filter should I use? I’ve heard something about an extra washer or something that needs to be replaced as well… is that true? If so, what is it called, and what brands are the best?

And here’s the big newbie question of the day… Where is the Oil Filter, what does it look like, and how do I remove/replace it? Like I said, I’m new to changing oil, and want to get off to a good start.

I am grateful for any help you guys can provide. Thanks!

[03WRXMA]

Lets see...


You are correct in your steps. After you crack the drain plug open the oil fill cap to help it drain also. Synthetic oil is completly compatible with dino oil, no extra is needed. I recommend the Subaru filter, nothing wrong with it at all. The 'extra washer' is the drain plug washer, they are cheap, and its best to replace it with every change. Lastly, the oil filter is commonly white. You really cant miss it under the motor! To remove use an oil filter wrench, but dont use the wrench to put it back on. Just hand tight, then 1/2 turn past once it makes contact is enough. Also make sure the old filter o-ring is off the oil filter housing otherwise it will leak. Remember to lube the new filter o ring with oil, and prefill it before install.

Best of luck!

[03WRXMA]

Has anyone else had this happen? Just did the break in period end oil change. Drove the car to work. Just checked it and I can still see trace amounts of metal in the oil..... Anyone? I think I may change it again.

[Lance]

I would keep a careful eye on it. Maybe send the oil in for analysis.

[03WRXMA]

Originally posted by Lance
I would keep a careful eye on it. Maybe send the oil in for analysis.

Im not too happy, that damn car has 1020 miles on it! I dont now, maybe the dealer is cheap and didnt change the filter.... I think I will change it tmrw and keep an eye on it, if I see further metal back to the dealer, and some out for analysis, do you agree?

[SD_GR]

Analysis won't hurt certainly. But you will probably get very whacky numbers - maybe high Si from assembly lube, high Cu from the oil cooler etc. Be sure to tell the lab it's a 1.2k mi motor and they should be able to tell you if anything out of the ordinary is going on.

[03WRXMA]

Originally posted by SD_GR
Analysis won't hurt certainly. But you will probably get very whacky numbers - maybe high Si from assembly lube, high Cu from the oil cooler etc. Be sure to tell the lab it's a 1.2k mi motor and they should be able to tell you if anything out of the ordinary is going on.

Good info, thanks! Did anyone else ever see these metal 'bits' before when their WRX was new?

[SD_GR]

I didn't change the factory fill until 3k mi like the manual says, and I let the dealer do it at that - so I couldn't tell you about the shavings. How sure are you they are metal? Can you chop open the used oil filter? Did you have any consumption?