Simple question about oil changes

[Thirdeye]

My sticker on my windshield says I should get my oil changed at 3/23/05, 121,--- miles, but i'm only at about 119,800 miles, should I get it changed at the date even though i'm not even close to the miles yet, or would it be safe to just wait until I get to the 121,400 or so miles?

 

[JNasty4G63]

Changing the oil in a car is all about wear. If all you ever do is drive to Taco Bell and get a snack at like 40mph at barely over idle, you can probably go like 10K miles inbetween changes. But, if you drive like you're setting a benchmark time, like I do, you can and should change often. The dates and mileage they give are just a rough estimate. The time doesn't mean anything though. I mean, if the car just sits and gets driven once a week, it isn't getting a lot of use, and the date will be way ahead. Just go by how hard you are on the engine. The harder you drive, the faster the oil breaks down and needs changing. If you are hard or mildly rough, change it every 2-3K. If not that hard on the engine, give it a while. But, the way I look at it, it doesn't hurt to change, so better safe than sorry.

Hilg

 

[Thirdeye]

I only drive it once a day, for about 5-10 miles (just to school and back), and it's not driven on weekends, but I do tend to drive it a bit rough, so maybe I should just get it.

 

[Jmac279]

Oil changes are probably the most important maintainance for an engine ...

Personally, I'd rather pay $30 every 3 months and get an extra year before it needs a rebuild than to pay $30 every 4 months ... I'd do it myself and save another $10, but my local Honda dealer gives washes and vacuums your car, too ...

 

[Takumi Fujiwara]

Actually, it's worse if you make lots of short, low speed, trips. That means you're doing a lot of driving with the oil still cold, which isn't good. It's more important to change it in a case like that.

 

[TS1AWD]

Also depends on what grade of oil you use. A thin oil such as a synthetic needs to be changed more often beacuse it breaks down faster. But a heavier thick oil can go longer between changes.

 

[Ev0]

Since we're on the topic, what is the proper way to dispose of old oil?

 

[JNasty4G63]

Actually, it's worse if you make lots of short, low speed, trips. That means you're doing a lot of driving with the oil still cold, which isn't good.

Its not good on the engine, but when talking about the oil in the engine, its not necessarily bad. Oil breaks down and stops working well with heat and hard use. If all you ever do is doddle around town at low speed, the engine doesn't ever get real hot. Many cars now have adaptive oil change indicators. Take BMW for example. They suggest the first change at 15k. But, thats just the base starting point. If you drive a little harder and faster than the average person, the ecu will adapt to that, and the oil change intervals will shorten. Its all about use and abuse. Drive like your on social security, and the oil doesn't break down as fast. Drive fast and hard, and it does.

Also depends on what grade of oil you use. A thin oil such as a synthetic needs to be changed more often beacuse it breaks down faster. But a heavier thick oil can go longer between changes.

See, I also don't think that is true. The thickness of the oil doesn't dictate how well it holds up to breakdown. Its the makeup of the oil. Yes, synth is slicker, but it actually will last just as long, if not longer. Thats why you see some oil makers selling "extended use" oils. But, the only time you see those is with synthetics. Conventional oil just doesn't have the chemical makeup to do that.

Hilg

 

[Takumi Fujiwara]

Since we're on the topic, what is the proper way to dispose of old oil?

Don't know about where you are, but, down here, auto parts stores accept used oil for disposal. Just make sure it's in an approved container, and that it's pure oil, nothing else in it.

 

[neanderthal]

Also depends on what grade of oil you use. A thin oil such as a synthetic needs to be changed more often beacuse it breaks down faster. But a heavier thick oil can go longer between changes.

👎

Changing the oil in a car is all about wear. If all you ever do is drive to Taco Bell and get a snack at like 40mph at barely over idle, you can probably go like 10K miles inbetween changes.....

👎

where do you people get MISinformation like this from? its really scary that this guy is being given incorrect info.

the "thickness" of an oil (also known as its viscosity) is not dependent on whether or not its synthetic.

synthetic oils are MORE resistant to breaking down than dino oils. that means standard non synthetic oils will break down faster than synthetics

short trips are more harmful to your car than long ones.

driving hard is harder on your car than cruising down the freeway.

to whoever started this thread.
change your oil regularly. how regular depends on how you drive. if you do mostly short trips, if you drive hard etc etc do it more frequently.

if you commute and do fifty miles each way on the freeway, you can get away with extending your interval.

if yoru car has a lot of oil, again you can get away with a long interval. if its only four quarts, not so much (ie. my 1976 BMW 2002 has about four quarts capacity. my 300E has almost twice that.) most japanese and econocars have little oil capacity.

oil changes are usually at 5000k or more if you read the owners manual. the oil change industry has made us believe its 3000. thats so you can do it more frequently and they can make more money.

 

[JNasty4G63]

.....where do you people get MISinformation like this from? its really scary that this guy is being given incorrect info......the "thickness" of an oil (also known as its viscosity) is not dependent on whether or not its synthetic......synthetic oils are MORE resistant to breaking down than dino oils. that means standard non synthetic oils will break down faster than synthetics......short trips are more harmful to your car than long ones.....
driving hard is harder on your car than cruising down the freeway.

Uh, is that not what I was saying???? Did you read what I wrote??? Yes, short trips are bad on then engine. That we know. But, the oil isn't breaking down any faster on short trips. And since he was asking about oil changes, thats what I was talking about.

if yoru car has a lot of oil, again you can get away with a long interval. if its only four quarts, not so much (ie. my 1976 BMW 2002 has about four quarts capacity. my 300E has almost twice that.) most japanese and econocars have little oil capacity.

The reason for the small capacity is because of the small engines. Sure, if you had 8qts capacity for a Civic you could go a little longer because the ammount of "clean" oil is more per the size of the engine. But, as the engine gets bigger, so does capacity. So, the ammount of oil per engine surface area stays relatively constant. I've never used the capacity as a guage for oil change interval. What was that you were saying about MISinformation????

Hilg

 

[Jmac279]

I think everyone needs to read this ...

http://www.trustmymechanic.com/motor-oil-bible.pdf

 

[Slick Rick]

I changed the oil on my car for the first time yesterday.
I only had 2.? litres of 10w40 in the garage which wasn't enough so i went to the petrol station intending to buy a top up bottle of the Castrol GTX 10w40 but then i saw a shiny gold bottle with words like 'edge' and 'sport' so i bought it
It was Castrol edge sport 0w40. I checked on the Internet first and the site recommended 0w30 so i knew this oil would be ok.
Anyway here's my question: I mixed roughly 2 litres of 10w40 with 1 litre of 0w40. Is the oil in my car now something like 7w40?? Is that how it works?

 

[Danoff]

Synthetic oil can go longer between changes. Synthetic oil can also be purchased in multiple weights, and is completely independent of oil weight (which is also completely independent of wear speed to the best of my knoweldge).

In otherwords, synthetic can be thick or thin, and which kind you should get depends on the mileage of your car and on your type of engine.

Short trips on a car allow condensation to build up in your oil and can reduce it's protection. If you usually get up to highway speed, I wouldn't worry about the expiration date on your oil change (if you're using synthetic). On the otherhand, if you never get up to speed and are turning your car off when it's relatively cold, you should consider changing your oil near the expiration date.

The recommended mileage and times for oil changes are significantly more frequent than necessary. That being said, I'd recommend going to synthetic. You get more time between changes, and it's better for your car in the meantime. Given the additional time between oil changes it doesn't cost much more (if any) than regular, and you can be snobby about your oil and look down on people who don't use it (oh, and it's better for the car).

 

[Duke]

Thank you neanderthal and danoff for good words, as well as Jmac for an interesting (if long winded and not necessarily 100% gospel) link. You guys have mostly cleared the air. In addition to the info already offered, I'll tell you what I do.

I run Mobil1 (which is rumored to not be 100% sythetic any longer) and Mobil1 or PureOne filters. I drive a mix of local and long distance driving, probably less than some.

I change my oil and filter every 5,000 miles, but never less than once a year, no matter how few miles I drive. When I had the head off my Neon's engine, it was nice and clean inside after approximately 6 years of this regimen. In fact, on a couple occasions I went to 7500 miles in that car, though I try to stick with the 5k interval.

If you're not using full- (or even mostly-) synthetic oil, you probably want to change in the 3k-5k range.

 

[Pupik]

Every manufacturer has their own oil change schedule; but if you're a member of these forums, the more severe schedule of the two suggested by the manufacturer probably describes your driving habits...hard on the accelerator pedal! Some want you to change it every 3000 miles, and some manufacturers even recommend you use full-synthetic oils that can go as far as 15,000 miles. So it all depends on the manufacturer's suggestion; it was put in the manual to cover their hides in case of internal engine component failure.

Don't rely on the oil companies and big-name general service shops to tell you when to change your oil; that's like Coke and Pepsi telling you when you should have another soda. They all insist you get it done every 3000 miles and every 3 months, regardless.

The overall advice in my shop for all cars over 100,000 miles is to be careful about when you change the oil; don't wait too late to change it even if you're not yet at the prescribed mileage. You never know, the mechanic could have looked at the mileage wrong, for all you know!

If the manufacturer suggests you change it every 5000 miles or 6 months, then change the oil at least twice a year, just to be on the safe side. That's my advice.

I've had more than one engine have oil gelling (mind you, Toyota's 3.0 V6 was a somewhat prone to this if neglected) because the owner followed the wrong maintenance schedule (South Florida climate and traffic are quite demanding on engines to recommend the "severe" schedule on just about any engine) or thought that since "Manufacturer X says to change it every 10,000 miles...then it's okay for my car".

I think the full-synthetic oils are best for engines recommending them; I know that Toyota makes no exceptions or special provisions to the mileage intervals by using synthetic oil.

Better safe than sorry, though.

 

[skip0110]

I changed the oil on my car for the first time yesterday.
I only had 2.? litres of 10w40 in the garage which wasn't enough so i went to the petrol station intending to buy a top up bottle of the Castrol GTX 10w40 but then i saw a shiny gold bottle with words like 'edge' and 'sport' so i bought it
It was Castrol edge sport 0w40. I checked on the Internet first and the site recommended 0w30 so i knew this oil would be ok.
Anyway here's my question: I mixed roughly 2 litres of 10w40 with 1 litre of 0w40. Is the oil in my car now something like 7w40?? Is that how it works?

What car is it? 10w40 sounds a little heavy for a gas engine, especially a modern one. If 0w40 is what your engine needs, you should give it something near that. If you live in a cold climate that 10w is going to cause a lot of wear when you start your car up.

Although, it is okay to mix viscosities, but not great because you end up with the wrong weight oil.

EDIT: As a matter of interest, I use Castrol GTX 5w30 and Fram ToughGaurd filters (which are crap, I know). I had a bad experience with Pennzoil (broke down after 4k miles completely, to the point that there was orange foam in the oil and visible layers), and my dad had a bad experience with Mobil 1.

 

[Slick Rick]

What car is it? 10w40 sounds a little heavy for a gas engine, especially a modern one. If 0w40 is what your engine needs, you should give it something near that. If you live in a cold climate that 10w is going to cause a lot of wear when you start your car up.

Although, it is okay to mix viscosities, but not great because you end up with the wrong weight oil.

EDIT: As a matter of interest, I use Castrol GTX 5w30 and Fram ToughGaurd filters (which are crap, I know). I had a bad experience with Pennzoil (broke down after 4k miles completely, to the point that there was orange foam in the oil and visible layers), and my dad had a bad experience with Mobil 1.

Ahhh finally! Just the answer i was looking for!
Thanks

Yea i was getting the feeling 10W40 seemed a bit thick for my little 1.4 The car shudders at low rpm if i put my foot down and someone said its probably down to the oil so tomorrow ill have to change the oil...again. The driveway already has a lot of sawdust put down from when i spilt some yesterday

 

[Slick Rick]

One more question: Why would a thick oil cause wear at startup?
If anything i would have thought a thicker oil would protect my car when starting up...

 

[Wolfe]

Almost everything has been covered already, so I'll just bring up one point --

If you have an old car that has used fossil-based oils for its entire lifetime, don't switch to synthetic oil.

Synthetic oil is designed to eat away at deposits in your engine. This is good for new engines, because it prevents these deposits from forming, and keeps your engine "clean" on the inside. However, on older engines, these deposits are often located on/near old, rotten seals, and are often the only thing still keeping the engine from leaking oil.

Switch to synthetic on your old car, and you may see that brand-new oil in a puddle on your driveway. Save your money and go for the old-fashioned stuff if your car is 10+ years old.

 

[skip0110]

One more question: Why would a thick oil cause wear at startup?
If anything i would have thought a thicker oil would protect my car when starting up...

When the engine is cold thick oil is like molasses so it will take a long time to get to all the moving parts, especially the top end of the engine like the valves. Oil never really flows, it just kind of oozes out to the top of the engine.

When the oil gets hot, it gets thinner. If it is too thin then it will drain away too quickly and not stick to parts and lubricate them.

A 5w30 oil will act like 5 weight (thin) when it's cold, and like 30 weight when it's hot (thick oil, but thinner when it's hot).

 

[retsmah]

Since we're on the topic, what is the proper way to dispose of old oil?

Around here you can put it out with the rest of your curbside recycling and they'll take it.

 

[FoolKiller]

Since some people here seem to know a bit about the synthetic oils:

For the first time ever I have a car that uses synthetic from the moment I drove it off the lot. The dealer and manual suggest an oil change at teh first 5,000 miles and then every 10,000 after that. I've never used the synthetic before so I didn't know how well this would actually work and was planning to change my oil with every tire rotation (3,000-5,000 miles) as I always did with past cars.

Is the every 10,000 miles recommendation fine? If that's the case then I will be looking at changes every other tire rotation, despite my manual suggesting rotations every 10,000 miles.

 

[Duke]

If that's what they recommend, then go for it. 3000 miles is definitely too short for synthetic oil - I'd go at least to 5000. Check and see if any of the 'severe duty' criteria applies to your driving, such as frequent short trips, etc. If not, consider 7500-10,000 as they recommend, but stick with their recommended oil.

 

[FoolKiller]

If that's what they recommend, then go for it. 3000 miles is definitely too short for synthetic oil - I'd go at least to 5000.

Thanks, I've just never used synthetic before and honestly had no clue how it works.

Check and see if any of the 'severe duty' criteria applies to your driving, such as frequent short trips, etc. If not, consider 7500-10,000 as they recommend, but stick with their recommended oil.

I have a 40 mile, one-way, drive to work so I rarely do a short trip. I guess I will be going some time between oil changes.

Thanks for the information.

 

[Slick Rick]

Well this morning i got rid of the 10w40 i put in the car on Monday. I was really surprised. Its only been two days and the oil was pretty dark already even with an engine flush. Anyway the shop guide and Internet recommended i use Castrol Edge 0w30 but that was £42 rip off!! so i bought Castrol GTX magnatec 5w30 for a more reasonable £25. Is Magnatec fully synthetic? It didn't say on the bottle...

Took it for a quick test drive and it feels a bit more lively at low rpm, not much difference at high and its also feels smoother which was predicted and is also a lot quieter when idling which was a surprise!

 

[YSSMAN]

...I've been getting my oil changes done about every 3-4K miles on my Jetta, which uses 5w30, apparently Valvoline being the choice at my dealer.

(I would do it myself, but like others have said, they vacuum and wash it. Big plus!)

I try to keep track of my oil, and I've noticed that it takes quite a while to get that hint of dark color, and then it will usually go fairly fast. I don't run her very hard, and most of the driving I do is at highway speeds (50-65 MPH), so she is doing pretty well I guess.

---

In terms of the cars in my family, we've always changed the oil at 3K or 5K miles, depending on what the manual says, or when the warranty-covered changes are free. Doesn't necessarily mean they need it, but it is good to keep things fresh I suppose.

 

[skip0110]

Well this morning i got rid of the 10w40 i put in the car on Monday. I was really surprised. Its only been two days and the oil was pretty dark already even with an engine flush. Anyway the shop guide and Internet recommended i use Castrol Edge 0w30 but that was £42 rip off!! so i bought Castrol GTX magnatec 5w30 for a more reasonable £25. Is Magnatec fully synthetic? It didn't say on the bottle...

Not sure...in the US all the Castrol synthetics are under the Syntec brand, Magnatec seems to be UK-only, but from what I saw on the internet it seems to be just semi-synthetic.

 

[blargonator]

Almost everything has been covered already, so I'll just bring up one point --

If you have an old car that has used fossil-based oils for its entire lifetime, don't switch to synthetic oil.

Synthetic oil is designed to eat away at deposits in your engine. This is good for new engines, because it prevents these deposits from forming, and keeps your engine "clean" on the inside. However, on older engines, these deposits are often located on/near old, rotten seals, and are often the only thing still keeping the engine from leaking oil.

Switch to synthetic on your old car, and you may see that brand-new oil in a puddle on your driveway. Save your money and go for the old-fashioned stuff if your car is 10+ years old.

not necessarily true^, i'm running mobil 1 10w30 in my 1982 toyota and its at 265k. i'm coming up to a oil change as i drive atleast 350 miles a week.

 

[retsmah]

Synthetic oil is designed to eat away at deposits in your engine. This is good for new engines, because it prevents these deposits from forming, and keeps your engine "clean" on the inside. However, on older engines, these deposits are often located on/near old, rotten seals, and are often the only thing still keeping the engine from leaking oil.

The best thing to do would be to switch to synthetic and replace any seals that are bad. But if you aren't prepaired to replace old gaskets then yeah you probably shouldn't be switching to synthetic.