How often to change oil?

My gf has a 2003 pic related and she seems to think that she needs to have the oil changed every 3 months because the sticker from the oil change place says so

How often should it be changed?

Every 3k-5k or 3 months

should be good for 30k miles, oil and filter technology has improved to this point but oil change places still use the old intervals to increase revenue

This guy probably works for Jiffy Lube, that's the exact same kind of shit they always say. Don't trust him.

I said 3 months in the op but I meant 3k miles

30000 to 35000 miles, just do it every time you get new tires

It depends on the type of oil you use
Mineral oils will degrade quicker than Synthetic oils, so if you're using a Mineral oil you should change it every 5-10k, Synthetic oils between 15-20k

That being said, with synthetic oils you can go 40k+ without changing it, but you run the risk of additional wear and tear, build up of sludge which can block up filters, veins, gallerys etc, and ruin seals.

what are you on? 10k (or more, depending) is fine with synthetic and a high quality filter. To be safe I wouldn't go past 5k on conventional because the pour point depressants break down and the viscosity increases and you lose lubrication. If you really want to know the exact interval for your car/oil/filter/driving habits, you can get an oil analysis done, they're like $30.

overall what matters way more than drain interval is that you check your fucking oil levels before the oil pressure light comes on

listen here fuckos, I spent the last two hours researching oil benchmarks to satiate my autistic hunger and I'm about to enlighten the fuck out of you

First and foremost, synthetic oil this side of the millennium is better than any semi or normal blend. No contest.

Secondly, let's talk oil weight. Your car will have a recommended weight, that's bullshit. Unless you live in Florida, California, or north africa, you will want to run a 0w __ oil in winter, and as long as it stays above 50~ in your summers, a 5w __ in summer. The second number varies based on your car. Rule of thumb, you want to run the thinnest oil you can. Thinner oil = better lube = better MPG because engine internals are gliding smoother, meaning less energy loss. Tl;dr thinner oil = efficient. I run 5w20 in summer and 0w20 in winter. I would recommend doing the same unless you are getting engine knocking or oil leaking, in which case move up to the __w30.
Notable exception here is for heavy duty trucks, Diesels, and certain picky V8s, as well as track cars. I didn't bother to look those up so go fuck yourself.

Third, let's go into oil rating. There are two important groups to look at here, SAE and API. The two work together, more or less. Every major oil brand is going to be SAE certified. The API rating, of course is more important. You will generally want to run newer (SN) stamped oil, besides niche scenarios with older cars.
1/2

Fourth, let's quickly cover the purpose of oil. To lubricate your engine, prevent buildup (sludge), and to cool the engine. Synths will have detergents to prevent sludge, I didn't bother researching all the gimmicks the companies do here. Lubrication can be measured by warm and cold viscosities, there are hundreds of charts posted online about them. Most of your engine wear occurs at startup, back to why you want to run the thinnest oil possible.
More flowing at cold = less engine wear = happy car.
Synths will break down or start to separate once they hit something above their rated warm weight is. This will lead to shortened oil life. This right here is the only reason to run thicker oil weight asides from reasons listed above. Tl;dr hot place with 100f+ heat index, run __w30

Fifth, let's talk intervals.
Every single one of you fuckos is right, and wrong. It's not about the interval, it's about three important things, only one of you mentioned.
>What color was the oil when I put it in, and what color is it now?
If your answer is a dark brown, or even worse black, your oil is near the end of its life of being an engine tampon. Change it.
>Are there drastic temperature swings?
This goes back to the above. If you run lightweight oil in winter and its now 80f and climbing in May, consider changing to your summer oil.

Cont. in part 3

tl:dr
>It's a 2003 shitbox

You're not as informed as you think you are.
Making the call for everyone to run 0w20 in their cars is beyond retarded.
You're right that the thinner it is in the cold the less engine wear, but also a 0w oil will break down faster than a 5w for the same operating viscosity.
You should run oil based on manufacturer specs and based on oil pressure.
The seasonal temperatures have minimal effect of operating temperature, so running a thicker oil just because it's warming outside can be stupid.

>lastly, how much oil is left?
No oil is bad. Your engine becomes a screeching bitch, just like that bloated hag you share a duplex with. If you are noticing low oil, and you are not having any oil leaks (check again you fuckers, this is important) then move up to a heavier weight oil, because your engine is finicky and burning off that lighter oil. Also check and make sure thermostats/cooling systems are working properly.

Now, the last part. There are several benchmarks all the major brands use, I didn't bother to pour over them because I can't be fucking bothered to waste another 4 hours while my ramen gets cold, but here's what you need to know.

There is no real clear winner in the oil department as of now. Every oil company says theirs is the best and spins statistics to make it look that way. I will name a few brands that seem to be at the top across all benches, and then Autismo Supreme will loiter briefly for the Q and A.
>Amsoil Signature
>Pennzoil *ultra* Platinum (theres a difference)
>Mobil 1 (didnt look up the specific brand)
>Quaker State (didnt look up specific brand)
>Castrol (Edge?) looked bad iffy in a few benches
I think I'm missing one, but this concludes oil autism 101.

Now fielding questions

tl;dr change it when
>temp goes from really hot to really cold or vice versa
>you are low on oil
>oil is darkened

You're missing out on the fun user, go read it.

I specifically said, drastic changes in outside temperature.

>everyone should run the thinnest oil possible
turbo is kill

A 0w30 and a 0w40 will be essentially the same viscosity on a cold start.

But the 40 in the summer will run higher pressures than the 30 in the winter.
Oil temps do not vary drastically based on weather, you'll only have issues if you're idling for hours on end.

And oil color is not an indicator of oil health.

the w stands for winter not weight, refers to viscosity when cold.

I was going to go more into depth, but dinner just came out.
Higher compression engines prefer thicker oil. I should've grouped turbos into track cars.

I've only used Pennzoil and Mobil so far, and in both cases they started off gold. If your oil is naturally black from the beginning, this will not work for you. Pic related

And to address the other half of your question, yes, thinner oil may break down earlier. Modern oil has become "good enough" to where you can run the thin stuff, and still hit your recommended intervals. Running thinner oils gives you the tradeoff of "It'll break down earlier if I run it hotter, while also giving me better performance". That is a tradeoff I take, but I cannot speak for how lazy you are. I do once every 6 months, because I'm picky about my car, but you could probably run 5w or 10w whatever year round and it'd be "good enough".

I read it differently but the end result is the same. You say potayto, I say potahto. I look at it and see 0, warm 30. I know that's not how it is but that's how I understand it. Whatever works for you

modern synthetics are good enough to go longest service intervals with just topups.
baka just because oil is black doesnt mean its bad.
continue wasting your money L O L

Oil doesn't start black, but just because it's black doesn't mean it's past its service life.

And to address the other half of your question, yes, thinner oil may break down earlier.
I didn't say thinner oils broke down earlier, a 0w40 will sheer quicker than a 5w40, that's not a thinner oil, it's just a wider ranged multi grade oil.
Running thinner oils gives you lower oil pressures, louder engines, improved fuel economy, unnoticeable power increase.
Running thicker oils gives you engine longevity and a quieter engine.
Running a wider multigrade oil gets you less start up wear, but in turn you should be changing it more often.

Oil selection doesn't need to be about your feels and which oil you like best, it needs to be about your engine and what works best and what maintenance you can keep up with.

My car that calls for 20w60 would explode under your recommendation of 0w20, I use 10w60.
My car that takes 10w50 would run retardedly low oil pressures and grenade if I ran your 0w20, I run 0w40 in the winter and 10w50 in the summer
And yes that means my operating tem oil pressures do run on the low side in the winter.
My car that takes 0w40 would likely become a rattle trap and significantly lower engine life if I stuffed 0w20 in it/
My car that calls for 10w40 would scream a painful death if you stuck 0w20 in it.

0w20 is a very modern oil that modern cars are "designed" to take. It's to meet fuel economy standards.

You can usually guess the recommended oil based on the vintage and type of car.
OP's car more likely than not calls for 5w30, and in that shitbox the last thing you need to worry about is the oil.

Now we're having fun

riddle me this, Batsy. How many of your cars fall into one of the three categories
>Older than '90 (old engines like heavier oil)
>turboed/engine is no longer stock/higher than normal compression
>Diesel

And I bet one of those 40 weights is a Beamer. Call it a gut feeling.

Now then, onto the actual statements.
I agree with most of what you're saying, with a few nitpicks.

To clarify, thinner oils should be used when possible, and at higher mileage or when engine is knocking (gosh, someone must've just said this?) You switch to the higher weight oil to reduce engine wear once its "older", older being a subjective term. A quick google search does show me that your post isn't necessarily correct, because I was curious. Your derivative tradeoff area is going to be, at what point is engine wear during driving with a lighter weight oil WORSE than repeated startups with a heavier weight oil.

>Just because it's black doesn't mean its old
It's a pretty good sign you're headed that way, refer to the above pic for guidance.

Besides that, I pretty much agree with you.

Fuck the germans though, can't do anything right.