This has been an age old debate and multiple schools of thought on this, but figured I'd ask the folks on this forum on your honest opinion. I know the manufacturer specified oil change interval is mostly based on mileage and not going too much beyond that mileage without getting an oil change done. With synthetic oil, the change interval generally is higher mileage than the standard conventional oil change. From my point of view, if you meet or surpass the mileage threshold, it's best to get your oil changed at that interval.

Now what about the time-based oil change interval per manufacturer's specs, if you car doesn't reach that mileage threshold? Take for example a car that is garaged most of the time and is driven mainly on the weekends. I know oil itself sitting in a car doesn't affect the oil per say, but it's the moisture and heat when additives in the oil starts to degrade/breakdown. That's why for a car that doesn't see many miles per month, you'd want to ensure you drive long/far enough during that trip to have the oil sufficiently reach temperature and burn off any excess moisture in the oil itself. (ie. a < 4 mile roundtrip to the grocery store wouldn't be adequate).

That said, for people who don't drive much, I've read where people still stick to the manufacturer's time-based interval and still get their oil change despite not meeting the mileage threshold. I also know others (with synthetic oil) who have cars where they haven't changed oil for 3-4 years, but when they do drive their cars, each trip they're doing highway driving long enough for the oil to reach temperature. I'm in that second group, on 2 years now on my synthetic oil and roughly 1500 miles with that oil so far - and each time I drive the car, I get it to temperature through a combination of highway and local driving.

Do you think I absolutely need to change my oil now or am I still good for another 5000 miles? I've seen and heard very conflicting answers to this... just curious what the true answer is and your thoughts. I'm sure all of your oil change locations would want your business, whether you needed an oil change or not. One fact/data-based Youtube video I did see was from Project Farm (I think) where the person analyzed what happens if you didn't change synthetic oil for longer than a year and the results showed no difference, as well as no additional wear internally in the engine.

 

To be fair... there was a small difference. Was it a bigger difference than you'd get by driving more miles in a shorter time? Absolutely not. However, there are many factors contributing to this, especially climate.

Personally, I would still change the oil after I hit the two year mark, if not earlier.

You have an IS, just enjoy it! Even though I work from home, I am still driving it about 1000 miles a month just because I can. That's off-topic, but either way, it's a much more known domain of cars that are regularly driven versus seldom driven, especially when it's a daily-driver-type car like an IS.

 

I am one of those guys who don't drive my "toys" a lot but despite this, I still do my oil change once a year, and I think it is part of the warranty thing where it says do your oil change at least once a year, but I could be wrong.

 

I have a 2021 Camaro SS and a 2001 Trans Am that are my car show, cruise, weekend driver cars. I have always had show cars that do not get many miles on them in a year. I have always changed the oils at the 1 year mark regardless. Cars cost a lot of money and so do repairs. Changing the oil is very very cheap insurance. I personally believe once a year they should be done.

 

The answer is simple.

Every 5k or every 6 mos which ever comes first.

No opinion, no debate.

Will your car blow up if you don't follow this? No. But it's for optimal results, aka for enthusiasts.

E46CT out

 

My owners manual says 10k / 1 year oil changes. The 5k/6 month service visits dont include oil changes.

 

Would you drink water that was sitting around in a dusty room over a year old? That's another analogy my mechanics give me.

 

Not sure if that analogy would work since the oil is in a sealed area in the engine, but I believe the issue more might be that the viscosity of the fluid might increase from it sitting which is why it's recommended every 6 months if you don't drive the car

 

Some one hear says annually is good time. I feel that way too as it’s also an easy way to remember. but only way to tell for sure is to send out ur oil to a lab and have it tested. It’s about $30 and they can tell you oil life, viscosity, water/coolant content. When I had my 08 is350, I was doin 5k/6months. I once drove 11k (25% aggressive mountain driving) in 6 months on synthetic, the lab says oil still had life and solid.

if you are under warranty, follow the manual, warranty can be denied.

 

Agreed 100% on this. When I was in NJ, it's 90% city driving but I only drive 30 miles/day so my rule was 4000 or 6 months whichever comes first.

I daily drive my car now for 100 miles a day(80% highway 20% city) and will reach 4000 in just two months. Still sticking with my old rule.

Oil is cheap.

 

Not sure why anyone would change at 4-5K miles when the manual says 10K. This car doesn't get regular oil, it gets synthetic... synthetic was made to last longer.. 8K-9K makes sense.. but 4K? "oil is cheap" but who really has the time to go to a mechanic wait an hour (that's being generous) or even jack up the car and do this whole process for a car that's engine has been around since 2008 and proven to last to 250K miles. Beyond me

I buy my own oil (mobil 1 synthetic) + filter + pay a mechanic $15 to change my oil which is probably the 'cheapest' way to do the oil change. This still ends up being minimum $60 which isn't "cheap"

 

Some of us have garages, tools and time to do it (and not to mention money). Most people call that DIY. My apologies for someone who does not.

Also goes the saying, take care of your car and your car will take care of you. Manual says 10K?, I say BS.

So by saying this, I'm not here to force someone do the same what I'm doing, just like I said, not everyone has a luxury of time, money and property - and for this I apologize.

 

No need to be so passive aggressive, I'm sure most people who own this vehicle have all those things you mentioned (including me). You bought a Lexus, not a BMW / Audi. If the manual says 10K, not sure why anyone in their right mind would go against that.

You don't even provide a good argument as to why anyone should change their oil at 4K-5K either, I am still confused as to why anyone would do this

You sound so condescending, we get it, you have money.. I don't think anyone who owns this car is struggling financially

 

You are free to think anything you want. If you're still confused as to why anyone would do what they do, then you need real help.

Heck, you call telling the truth condescending then hey I'm sorry. It's not my fault if I have what I have

 

Totally agree! I have been changing my oil every 5k since 30k miles - I now have 120k. Drive the car the way it is meant to be all the way to 7200 RPM I also add Techron Fuel Injector cleaner on my long trips to NJ/PA from MA which is quite often.

I don't believe the 10k mile oil change. At that point might as well believe that the transmission fluid is lifetime too.