Depends on the age of your car and the type of oil. New cars should easily be able to go 5,000 miles between changes, regardless of oil type, without issue. With full synthetic oil, a new car can actually go 15,000 miles between changes.

Older cars and vehicles that tow, operate in extreme temps, or operate in extreme conditions (i.e., mountains) may need it more often. But, with modern oil and synthetics, they should be able to go 5,000 miles without issue.

I go full synthetic and average 7,500 - 10,000 miles between changes for most of my vehicles. My C4 Vette still goes ever 3k and my 2010 Toyota FJ goes every 5k.

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If there are no dogs in Heaven, then when I die I want to go where they went. - Will Rogers

Emery's Third Coast Triathlon | Tri Wisconsin Triathlon Team | Push Endurance | GLWR

Oil gets dirtier and dirtier as its used. Synthetic oil is said to not break down as fast and protect from the dirt longer. That said I change synthetic at 6000 miles and conventional between 4 and 5000 miles. 8000 is really pushing it in my opinion.

As to your other question - very few oil indicators actually check the quality of the oil. Some merely go off the miles driven. The more advanced models use an algorithm and base the % life off of driving conditions (i.e., number of miles, temperatures, stop-and-go vs. highway miles, towing, etc.). So, they are good guidelines, but, the vast majority are not actually monitoring the specific quality of the oil in your engine.

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If there are no dogs in Heaven, then when I die I want to go where they went. - Will Rogers

Emery's Third Coast Triathlon | Tri Wisconsin Triathlon Team | Push Endurance | GLWR

Synthetic oil can last for a long time. I know Mercedes now says every 10k miles. My Subaru manual says I should only take synthetic and change every 8k miles. I hate it how every oil place tries to tell you every 3k miles, they are just looking for suckers. I would go by what the car manufacturer recommends.

It really depends. In addition to the considerations others have already mentioned, it depends on the quality of your oil filter, and your air filter.

I run 100% synthetic in a harsh climate, with lots of dirt roads. I typically change oil and filter every 7-8,000 miles, and I always try to start the winter season with clean oil and filters.

One year old vw 1.4 tsi just had oil changed at 24k km.

Next oil change due in 30k km

Send a sample to blackstone labs. They will tell you exactly condition of oil so you know if You can go longer. Well worth $25

Often the "warranty price" is from full retail so you can easily get the 1/3 off by shopping around. This goes for tires, batteries, etc., and even more so if you are getting work done at a dealership.

If you have to pay for rotations then consider that into your total cost as well. 5K seems too often for tire rotations on a normal vehicle...that tire would be changing 11 times over it's lifetime! I do it at about 10K on my soft tired vehicles (AT tires on truck). On my BMW's they have always said don't rotate.

I do oil changes at 10K with full synthetic, although the manual says you can go 15K under normal conditions.

From the research that I've done, this is the correct answer. Synthetic oil does not break down as fast, but still gets dirty. Oil manufacturers that are marketing their synthetic oil as "15,000 miles" are doing just that--marketing. My car requires full synthetic and the manufacturer's recommendation is every 5,000 miles. There's no way in hell I'd push that to 15,000 miles.

As others have mentioned, just follow the manufacturer's recommendation.

A lot of modern cars that run full synthetic also have larger oil volumes. My BMW had a 15k interval with a condition based oil light - I usually got to around 10K before it indicated a change as I drove mostly city. That car also took 7 quarts of oil vs. my Infiniti which only took 4.5 quarts and had a 5K recommended interval.

My current Volvo has a 10K or 12 month interval but it's not condition based, just a timer. It's a small 2.0 L 4 cylinder engine but takes over 6 quarts of oil.

I just follow the manufacturer recommendations and change when light comes on. I recall similar discussions on the BMW forums where people couldn't accept the 15K interval and it was all about BMW saving money on their service plans. Then there are the guys with 200K on their cars changing the oil every 15K or whenever the light comes on.

Most cars with high mileage intervals also have very specific requirements for oil. So it's not just synthetic, there are standards for the oil like LL01 which is BMW approved.

Volkswagen group warrantied my car for 7 years. Oil changed at 24k km. Next at 30k more.

They break it, they own it. I doubt that they'd be so foolish as to tell me that my car needs oil changes at that frequency only to own the problem whilst it's under warranty

Rotations are free and done .5 miles from my office. I drop it off at work and pick it up at lunch. 5K always made sense because that was when I got oil changes anyway. It's a large pick-up with four wheel drive. I also live on a dirt/ gravel road so I'm guessing I'll stick with the oil change every 5K as well. I'll admit that I'm a bit OCD but then again I'm on my 3rd car at 43 years old so previous cars have lasted 200K plus miles and 10+ years.

thanks

I'm gonna all you foreigners to use "freedom figures" in your responses. None of that commie kilometer shit.

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If there are no dogs in Heaven, then when I die I want to go where they went. - Will Rogers

Emery's Third Coast Triathlon | Tri Wisconsin Triathlon Team | Push Endurance | GLWR

It's actually really fucking annoying. Because the cars French whilst I have moved economy over to miles / gallon, all the rest of its measure in that continental stuff.........

I was really shocked though the day I picked it up and the guy said see you in two years for a service..........

yeah a pickup need more tire rotations than a passenger car...I see your logic. If I was expecting 40K out of the tires then the intervals that make sense are either 5K or 10K...either once per position or twice. Unless you rotate the spare as well and then it would be 8K.

Agreed.

Most folks change their oil way too often. We were all taught by our fathers that we should change the oil every ~3500miles and we've been victims of Marketing dept's ever since.

For the last 6yrs or so, I've been sending oil samples on my tow vehicle/daily driver, and on the race car. The purpose was to watch for unexpected engine wear, and to gather info on reasonable oil change intervals (OCI). After sample after sample, I started extending the OCI's, paying the extra couple bucks for the oil sample to tested for acidity (called Base Number), the usual test of remaining oil life.

I thought sure that I'd be changing the oil on the truck more often then the 10k OCI recommended by RAM because it does so much towing. And the load it right at its rated tow capacity so its a nontrivial effort.

In my early days in racing, many veterans recommended that I change the oil in the race car after every monthly event, call it 3-4hrs of track time.

With all these oil analysis reports encouraging me to extend OCI's, I stayed at the 10k interval for the truck despite all the hard towing, and to the outrage of all the deep pocket racing veterans, I change the oil on the race car every 18months.

The place to learn about oil, btw, is called BITOG. It stands for, and I'm not making this up, BobIsTheOilGuy.

Just get a high quality oil, and consider getting it a little thicker then spec. Chasing American CAFE standards have pushed recommended oil viscosity's down a bit, so they are a mite thin.

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2001 F150 4.6 L. 330,000 miles and burns no oil. I would not hesitate to get in it right now and drive across the country. When my truck was new it came with free oil changes and they said every 5,000 was good (conventional oil). Once the free oil changes ran out the dealership then said it would really be better for the oil to be changed every 3,000. Yeah better for their bottom line. That ticked me off and I decided to change it myself from then on. I use Mobil 1 full synthetic and change it about every 7,500 miles. I am now running the Mobil 1 Annual Protection which I think is claimed to be good for 15,000 miles. I will change it at 10,000. I believe the Mobil 1 oil has played a large role in the engine still being in great shape.

I became a huge believer in synthetic motor oils in the early 90's when I started using it in my 2 stroke outboards. The motors immediately idled far better and the morning smoke at the initial startup pretty much stopped. I was amazed. I personally would not put anything but synthetic oil in a crankcase unless it was a free oil change and even then I would have to consider closely.

Does anyone know if you can put synthetic in an Onan generator(or any generator for that matter)? Any downside?

Seems like there should be no reason why not... depending on its fuel source you would probably want to pick a gasoline or diesel specific grade but it's maybe a good way to keep the wear down. I would contact Onan for their view on it.

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Less is more.

Good luck with that strategy.

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"There are two novels that can change a bookish fourteen-year old's life: The Lord of the Rings and Atlas Shrugged. One is a childish fantasy that often engenders a lifelong obsession with its unbelievable heroes, leading to an emotionally stunted, socially crippled adulthood, unable to deal with the real world. The other, of course, involves orcs." John Rogers

It's not my strategy..........

I always just go by what the manufacturer recommends for both type and interval of oil change. If a car has had an indicator, I went by that. I also only go to dealerships for oil changes (so they have a record for warranty, and I keep receipts), once the powertrain warranty expires, I save a few bucks and do it all myself.

Of course, I am an ex mechanic that went to an Autotech school, the only time a shop touches my cars is when they are under warranty, its something I dont have the tools for (tire change), or something that I COULD get without a lift but it is a PITA.......like our old civic had to have the tensioner and belt replaced, well, without a lift it would have been a PITA, so for my sanity, I took it in.