synthetic oil distance

[jgurnari]

how many miles should i get out of my Synthetic oil? i do not drive the car hard and it has 305k miles.
911 1985 carrera

[DerkPerk]

I run synthetic oils on my daily drivers. The diesel truck goes 5k and the SUV goes 7.5k. I run conventional in the 3.2 that gets changes once a year no matter what mileage.

Synthetic oil can last a long time but can get expensive if changed too frequently. You can always have a sample sent in for analysis if you are wanting to wring the most out of it.

I feel oil changes are cheap insurance.


Sent from my iPhone using Tapatalk

[Trackrash]

Mobil 1 advertises 10K miles.

[RSTarga]

I change Mobil 1 every 5k or 6 months

[stownsen914]

Two reasons to change your oil:
1. The oil has broken down from use, heat, etc.
2. Remove the combustion by-products and debris that build up in the oil

Synthetic oil reduces the effects of #1. It doesn't help with #2. Personally I wouldn't go 10K miles between oil changes.

[Jeff Alton]

Why are you running synthetic in your 85 3.2?

As noted above, your oil also has to transfer wear materials and combustion by products to the filter.

Filter media for these cars really has not improved over the last 40 years. Combustion by products are still the same. Sure, oils have improved in ONE of their roles, lubrication.

Aircooled 911, 3000-5000 miles max, or depending on how far you drive, at LEAST once a year. Assuming street driving. Track use is a different story.

Oil/filters are cheap, engines are expensive.

Cheers

[winders]

Originally Posted by Jeff Alton

Why are you running synthetic in your 85 3.2?

Why would not not take advantage of the latest oil technology and provide better wear protection for your engine especially in hotter conditions???

I would have no problem running a street 3.2 on Mobil One 15w-50 for 6000 miles.

[Jeff Alton]

Scott,

I asked "why". Never said it was a bad idea. Assuming an oil with proper wear protections was used.

Do you have a street 3.2 running Mobil 1?

What do you run in your race car?

Cheers

[Bill Douglas]

I just do what other people tell me to do (haha, not really) so I use synthetic oil in all the vehicles and have "oil change day" once every 6 or 8 months. Strange thing is it came out of the SC quite dark looking although I haven't driven the SC much since the last oil change.

[fintstone]

IMHO, about the same as you would dinosaur oil (which is what I use in my classic 911s). I use Mobile 1 in my Cayenne as recommended.

[winders]

Originally Posted by Jeff Alton

Scott,

I asked "why". Never said it was a bad idea. Assuming an oil with proper wear protections was used.

Do you have a street 3.2 running Mobil 1?

What do you run in your race car?

Cheers

I used to own a 911SC with a 3.2L in it. I ran Mobile One 15w-50 in it and so did the person that bought it from me. We both changed oil at 6,000 mile intervals. When he had the engine rebuilt at 300,000 miles the main bearings still looked great. The rod bearing were really good too.

I use Driven XP6 in my race engine. The oil system holds over 4 gallons and it gets changed after 5 race weekends. Expensive.....

[IROC]

A buddy of mine (big car guy) runs Mobil1 in his Evo because it is cheap at Walmart.
He went on a personal journey to determine the best change interval. He advocates (and I have to agree with him) that oil analysis is the only way to really know. In his car, with his driving style, etc., he found that even at 10k miles, the Mobil1 was still fine.

He is a veteran of the "oil wars" on internet forums and he maintains that any opinion on change intervals that isn't backed up by data is just an opinion.

Having said that, I change my oil every 5k miles in the 5 family cars I maintain because it is easy to remember.

[T77911S]

have your oil analyzed.
they will give you an idea of how long you can run your oil
with my turbo, 5k. but much much more heat.

[AlKidd]

+1 on using analysis. I generally drive diesels, daily due to long commutes, which have longer recommended change intervals than gas equivalents. 10-12L of synthetic was adding up quick so I started getting analysis done. At 20% more mileage they were reporting a slight 2-3% degradation of the oil. That gave me my benchmark. The 911 gets a lot less driving so I change it yearly due to sitting as much as it does.

[Ctopher]

Originally Posted by IROC

A buddy of mine (big car guy) runs Mobil1 in his Evo because it is cheap at Walmart.
He went on a personal journey to determine the best change interval. He advocates (and I have to agree with him) that oil analysis is the only way to really know. In his car, with his driving style, etc., he found that even at 10k miles, the Mobil1 was still fine.

He is a veteran of the "oil wars" on internet forums and he maintains that any opinion on change intervals that isn't backed up by data is just an opinion.

Having said that, I change my oil every 5k miles in the 5 family cars I maintain because it is easy to remember.

Yep I agree with your buddy. I have samples from my Civic Si from first oil change to a few years ago. I changed early at 1900, then 50% the maintenance minder, then 5%, then 1k over all using GTX. A couple of samples over the years to confirm but in that car and my daily 8k redlines is fine for what the computer says. I am at 5% now after resetting the first oil change, running a second full run with Amsoil SS and same factory filter. Shoot Honda calls for filter changed every other time.

The Carrera will be sampled here shortly after 2yrs and I don’t remember exact miles running Amsoil ZRod. Will of course send a sample and either move up the change interval or keep it around 2yr mark depending on results.

Sampling over the life of the car should help find concerns. Example, my Maxima SE was hit years ago and you should have seen the metal and silicon spike on that change. If I ever have a small fender bender I would immediately change oil.

CTopher

[Tinkerer]

Changed once per year regardless of miles to remove toxins from the engine

Harley - Amsoil
Toyota- M1-EP
3.2 Liquid Moly with zinc additives

Like others have said oil changes are cheap protection plus I can check the magnet for debris

[ahh911]

Looks like oil change intervals are all over the place.

I assume only longtimers with 911, 100k miles input are most valuable, but for every 10k oil change, we'd need a 5k, 2k, to compare with similar driving, styles, good luck with that.

I hit over 5k rpm, pretty much 20 times a day? roughly, with full pulls up to 4th, every couples of days? Don't know, in my m3 this would be taking it easy, anyhow, 5k miles, 15-50 M1, but my input is meaningless because I've only put on 15k miles since owning it. 81 sc. At 3k miles pulled some oil, blackstone looked okay, but would you expect anything else?

The m3, syn, 7k rpm quite often but less than before, 6k miles, just changed it, ~ 2years old.

Phil

[pampadori]

Deep in my mind, I know that modern oil, especially good synthetic oil like what most of us use is capable of lasting up to 15k miles or more. I also know that it hasn't lost much of anything due to being in a seldomly driven car longer than a year. The oil tests confirm this.
But still I feel compelled to change it much more frequently than it needs.
I guess it's like how I give my dog a big rawhide treat every so often. She doesn't need the rawhide in order to survive or anything, she gets plenty of dog food. But rather it's to provide her with a treat. A bonus for being great!
Combine that with most of us are old enough to remember the oil industry telling us every 3k miles it should be changed, old habits are hard to break.

11 quarts and a filter as large as ours, we could probably go 20k miles without negative effects. It would make our carbon footprint happy to boot!

[Tinkerer]

Originally Posted by pampadori

Deep in my mind, I know that modern oil, especially good synthetic oil like what most of us use is capable of lasting up to 15k miles or more. I also know that it hasn't lost much of anything due to being in a seldomly driven car longer than a year. The oil tests confirm this.
…11 quarts and a filter as large as ours, we could probably go 20k miles without negative effects. It would make our carbon footprint happy to boot!

Agree that a quality synthetic will go 15k miles but the filters are usually good for only 5k miles.

[dfhtrhjn]

I change mine every 3k miles or annually. It's the cheapest service I can do that guarantees the internals are clean and slick. Compared to the cost of the motor, the oil is a no-op.