Oil analysis

[superflunker87]

I drive a lot (about 66% highway). My car is almost at 90000 miles and I change my oil anywhere from 7000 to 9000 miles. I always wondered whether that was too long of an interval so I did an oil analysis. Looks like 7000 is fine and I could go even higher if I want.

 

[socalvn]

Interesting I do 75% freeway driving and just let the dealership do it every 3k planning on doing my own moving forward with a better quality oil so may consider 5k the other 25% is a lot of stop and go with sport driving

 

[cwfl]

I do 90% stop and go in the city, and 10% highway, so I'm changing every 3k, just bought mobil 1 from costco, 6 quarts for $37 after tax.

 

[Snicklefritz]

Interesting I do 75% freeway driving and just let the dealership do it every 3k planning on doing my own moving forward with a better quality oil so may consider 5k the other 25% is a lot of stop and go with sport driving

KIA puts in Mobil full synthetic. Do you know of a higher/better quality than that? Shoot, every 3K miles with full synthetic, your car isn't babied, it's spoiled.

 

[socalvn]

KIA puts in Mobil full synthetic. Do you know of a higher/better quality than that? Shoot, every 3K miles with full synthetic, your car isn't babied, it's spoiled.

OK wasn't familiar with what they were using

 

[rtv900]

Interesting I do 75% freeway driving and just let the dealership do it every 3k planning on doing my own moving forward with a better quality oil so may consider 5k the other 25% is a lot of stop and go with sport driving

this is a total waste of money and resources.
absolutely pointless to change oil that often
you may as well throw $50 right in the garbage

 

[socalvn]

this is a total waste of money and resources.
absolutely pointless to change oil that often
you may as well throw $50 right in the garbage

$98

 

[Thomby]

Don't remember if it was Blackstone or maybe the Bob Is The Oil Guy blog (which references Blackstone test results) that had some interesting info about changing too frequently.

I believe the gist of it was that the first couple thousand miles of an oil change showed *increased* wear/metal content, due to the oil detergents, before leveling off, then eventually increasing again as the oil got dirty and old.

I don't think it was anything excessive, but it did point to the idea that more/sooner isn't always better.

 

[cwfl]

Don't remember if it was Blackstone or maybe the Bob Is The Oil Guy blog (which references Blackstone test results) that had some interesting info about changing too frequently.

I believe the gist of it was that the first couple thousand miles of an oil change showed *increased* wear/metal content, due to the oil detergents, before leveling off, then eventually increasing again as the oil got dirty and old.

I don't think it was anything excessive, but it did point to the idea that more/sooner isn't always better.

That's really ineresting. However it could also vary by different driving condition, for example most of the time I drive in the city less then 5 miles in a cold weather. So for me, maybe sooner is better?

 

[rtv900]

$98

more of a waste knowing you are paying 100 bucks
Even for a dealership honestly I'm surprised they haven't advised you to NOT waste your money on 3k oil changes
but then again maybe they did and you didn't care

 

[Thomby]

That's really ineresting. However it could also vary by different driving condition, for example most of the time I drive in the city less then 5 miles in a cold weather. So for me, maybe sooner is better?

Lots of short drives means more time spent with engine & oil cold, which can increase wear but wouldn't be fixed by frequent oil changes.

It could also mean more blowby and less time to boil off water & gas in the crankcase. More frequent oil changes might mitigate this, but I suspect it's minimal...you're probably still getting warmed up enough to get rid of most of it, and if you're not and it's accumulating drive after drive, an early oil change is only going to fix it temporarily.

But an oil analysis should be able to tell you if there's an issue or give you peace of mind. You could take a sample at 3000 miles without changing oil, and then again at 6000 with an oil change, and include it in the notes to see what they think.

 

[cwfl]

Lots of short drives means more time spent with engine & oil cold, which can increase wear but wouldn't be fixed by frequent oil changes.

It could also mean more blowby and less time to boil off water & gas in the crankcase. More frequent oil changes might mitigate this, but I suspect it's minimal...you're probably still getting warmed up enough to get rid of most of it, and if you're not and it's accumulating drive after drive, an early oil change is only going to fix it temporarily.

But an oil analysis should be able to tell you if there's an issue or give you peace of mind. You could take a sample at 3000 miles without changing oil, and then again at 6000 with an oil change, and include it in the notes to see what they think.

Thanks for the advice. I know short trips are bad for the engine, which is why I try to full throttle when driving on the freeway, althought It is still a myth for me if it is acutally helping to get rid of some of the carbon build up.

 

[Thomby]

Thanks for the advice. I know short trips are bad for the engine, which is why I try to full throttle when driving on the freeway, althought It is still a myth for me if it is acutally helping to get rid of some of the carbon build up.

If you mean carbon buildup on the back of your valves, that comes from a combination of the PCV (venting oily air from the crankcase back into the intake), and perhaps the EGR (blowing exhaust particulate onto the now-oily valves). You can put an oil catch can in line with the PCV to catch this before it hits the intake.

 

[Volfy]

That's really ineresting. However it could also vary by different driving condition, for example most of the time I drive in the city less then 5 miles in a cold weather. So for me, maybe sooner is better?

Take a look at Mike's take on problems with short drives. He is referencing mostly his daughter's STI running R85, but he also mentioned the same problem with running gasoline at the 2:17 mark.

The real "fix" for this is to take a longer driver every so often to burn off the moisture condensation completely out of the oil, but even Mike said more frequent oil changes would help to some degree.