When would you change the oil

MoneyJohn

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Thank you, folks.

It's a QG18DE engine. It does not leak or burn the oil (yet). I have been diligent about the maintenance since I started looking into it. All other fluids are changed within the last 2-3 years.

I ALWAYS change oil and filter before it hits 3K. Since this car was getting used for local errands, it rarely made beyond 3K a year. Once in a while, I would take a 100 miles round trip just to evaporate all the water in the oil and charge the battery fully. At the moment, I have using synthetic Mobil 1 5W-30. Since I have another Subaru Forester, I use 5W-30 in both vehicles. I will switch to high mileage for Sentra. Until now, I used to use oil change date as a reference because it never made more than 3K a year, but going forward will make more sense using mileage. I will switch to that.

Again Mobil 1 0W-40 is one of the best options available from Wal-Mart shelves. As well as Castrol Edge 0W-40, Quaker State Euro 5W-40, or Pennzoil Euro L 5W-30.
Mind elaborating on this suggestion. Since I don't understand the difference between the regular 5W-30 and Euro versions, I never looked at them. Never thought of 0W-40 either. I still have 15 quarts of Mobil 1 5W-30 left but I will use that for Forester.
 
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Thank you, folks.

It's a QG18DE engine. It does not leak or burn the oil (yet). I have been diligent about the maintenance since I started looking into it. All other fluids are changed within the last 2-3 years.

I ALWAYS change oil and filter before it hits 3K. Since this car was getting used for local errands, it rarely made beyond 3K a year. Once in a while, I would take a 100 miles round trip just to evaporate all the water in the oil and charge the battery fully. At the moment, I have using synthetic Mobil 1 5W-30. Since I have another Subaru Forester, I use 5W-30 in both vehicles. I will switch to high mileage for Sentra. Until now, I used to use oil change date as a reference because it never made more than 3K a year, but going forward will make more sense using mileage. I will switch to that.


Mind elaborating on this suggestion. Since I don't understand the difference between the regular 5W-30 and Euro versions, I never looked at them. Never thought of 0W-40 either. I still have 15 quarts of Mobil 1 5W-30 left but I will use that for Forester.
For a conventional oil it is OK for 3K mile OCI but for synthetic it is too soon. Buy the WM S/T HM synthetic or whatever is on sale & do a 5K OCI on your Sentra. It has 120K miles, just a little TLC & it will still be capable of hitting 250K miles or even more.
 
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Mind elaborating on this suggestion. Since I don't understand the difference between the regular 5W-30 and Euro versions, I never looked at them. Never thought of 0W-40 either. I still have 15 quarts of Mobil 1 5W-30 left but I will use that for Forester.
Euro rated oils are held to a higher standard, because they need to be able to meet a lot more stringent specs, as compared to basic API SL/SN/SN+/SP approvals. The more stringent specs require the oil to perform better as far as sludge & deposit control, oxidative thickening, wear prevention. As result a Euro rated 5w30/5w40/0w40 oil will be made from better base oils and will be packed with better/stronger additives as compared to a regular synthetic 5w30 that only meets API SP. End product is able to take a lot more "abuse", so to say... Considering that prices on both are usually the same, I personally don't see a reason to opt out for "good enough" API SP 5W30, when a much, much, much better oil is right there in Euro 5w30/5w40/0w40 form. Euro rated oils clean better, can hold up better in extreme conditions (lower/higher temps) against thermal breakdown, against oxidation, able to perform in a much wider range of duty cycles without degradation in performance. Same can't be said about every API SP 5W30 oil on the shelf... Euro oils are also believed to keep the piston rings cleaner, which is huge when it comes to engine performance, efficiency, and oil consumption.
Specs/approvals to look for on the oil:
- Porsche A40/C40
- MB 229.5 and up.
- VW 504.00/507.00
Click here: Here is what we know about Porsche A40 spec and the type of testing an oil meeting that spec has to pass. And from approvals I listed Porsche A40 is the least stringent one, if that says anything.

Now, don't take this as a message that Mobil 1 5W30 isn't good. It is better than many of its competitors. But... If something better is available for the same price, then why opt out for a less capable product? That's kinda my logic behind my oil choice. I run Euro oils in everything, from 4.3hp 49cc liquid-cooled scooter, to 4.6L V8 engines in family 375hp Hyundai Genesis and 310hp Toyota Tundra, and 20-ish engines in between. From what I learned on this website (through feedback of other users and hundreds of UOAs across various vehicles and usage patterns) - Euro rated oils are the best oils off-the-shelf. For a better performing oil the only next option is boutique oils, but that's another can of worms for a different thread...
 
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For a conventional oil it is OK for 3K mile OCI but for synthetic it is too soon. Buy the WM S/T HM synthetic or whatever is on sale & do a 5K OCI on your Sentra. It has 120K miles, just a little TLC & it will still be capable of hitting 250K miles or even more.
This post is too much of a blanket statement. Again - 5k OCI is a great choice, BUT NOT ON THE SENTRA WITH A 2.9QT SUMP CAPACITY. Yes, it will do fine for a little while, but within a couple OCIs it will start burning oil. There is simply not enough oil to hold all the deposits in suspension for 5000 miles over and over and over again. Soot and deposits (combustion byproducts of any internal combustion engine) WILL cause sticky (and eventually carboned up) piston rings, and may clog the oil return holes on the pistons. All the combustion byproducts of a 4-cyl, but with a smallest oil filter on the market, and such a small sump oil capacity, is a recipe for a disaster. Engine will become an oil burning smoke machine, that is getting worn down quite quick from all the deposits that are circling around and scoring the bearings and cylinder walls.
Your recommendation is correct for many vehicles on the road, except for a Nissan 1.8L engine in question. Or a Nissan 3.3L V6 from same era with a 3.5qt oil sump capacity. Both come with a tiny oil filter (easy to fill-up and activate oil bypass). Both of these need short OCIs to stay "healthy". Premium Euro oils help beyond bare minimum WM 5w30. Hope this makes sense...
 
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MoneyJohn

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@Vladiator

Thank you for your detailed comment. I try to avoid venturing into something I don't understand. So if I go Euro 5W-30 oil, does it come in high mileage form as well (could not find it on amazon/Pennzoil/Mobil website)

What is the rationale behind 0W-40?
 
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@Vladiator

Thank you for your detailed comment. I try to avoid venturing into something I don't understand. So if I go Euro 5W-30 oil, does it come in high mileage form as well (could not find it on amazon/Pennzoil/Mobil website)

What is the rationale behind 0W-40?
"High mileage" is just a marketing term, more than anything. Usually (between the same brand) HM oils do contain a sprinkle more of seal conditioners, anti-wear additives, and detergents. But when compared to Euro oils - Euro oils still have more of all this stuff, because Euro oils are usually targeted at extended intervals, so they pack more (and often higher quality) additives. And as I mentioned earlier - Euro rated oils are usually made from higher quality base oils.
In short, synthetic HM is a minor step up over "regular" synthetic oil, yet Euro oil is a major step up over both. If your car is not leaking oil - no need for HM oil. Some members actually had minor leaks "sealed up" after switching from regular synthetic to Euro rated oils. That tells me that it has at least the same or higher concentration of seal conditioners as a HM oil.
0W-40 just happens to be the preferred multigrade of the manufacturers. It covers a wider range of temps than 5w30 does, giving easier starts at extremely low temps, and less oil shear at extreme high temps conditions (towing/racing/summer stop&go traffic/long idling hours).

Edit: With Mobil 1 0W-40 FS in particular - it tends to be right on the edge between a "heavy" 30-grade and a "light" 40-grade oil. Same goes for Pennzoil Euro L 5W-30. Labeled as two different grades, but in real world they are very close in viscosity traits. They do however differ in additive packages. Both are compatible with each other, but for optimal performance stick with one or another. Castrol Edge 0W40 though is on the "heavier" edge of the 40-grade viscosity spectrum. Click here if you get bored and/or wish to learn about viscosity.
 
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