06-17-2008, 11:59 AM
06-17-2008, 12:16 PM
yup - there are a lot of factors that determine when to change your oil - this is especially true with cars like ours, which often are toys, and sit for a while between drives
the old 3000 mile mark was based on american cars, the tolerances of the rings and such, and the qualities of the oils at the time - nowadays, you can go 5k for sure on a daily driver, more with synthetic
however, if your car sits, be prepared to change it more often - i know this sounds contradictory - however, if you think about it, it makes sense
everybody knows that when your car sits, it tends to puff a bit when you first fire it up - this is due to the rings and such expanding and seating, and while doing so, it allows a bit of a mixture of fuel and oil - this contaminates the oil - that means that you need to change it more frequently than if you fired it up and drove it every day - the longer it sits, the more this happens
bottom line, sniff your dipstick - if it smells burnt or like fuel, the oil needs changing - also, take a paper towel and wipe the dipstick off on it - if you get dark rings around the edge of the oil, or it is dark all the way through, you need to change it - the oil should be clean and without deposits
the old 3000 mile mark was based on american cars, the tolerances of the rings and such, and the qualities of the oils at the time - nowadays, you can go 5k for sure on a daily driver, more with synthetic
however, if your car sits, be prepared to change it more often - i know this sounds contradictory - however, if you think about it, it makes sense
everybody knows that when your car sits, it tends to puff a bit when you first fire it up - this is due to the rings and such expanding and seating, and while doing so, it allows a bit of a mixture of fuel and oil - this contaminates the oil - that means that you need to change it more frequently than if you fired it up and drove it every day - the longer it sits, the more this happens
bottom line, sniff your dipstick - if it smells burnt or like fuel, the oil needs changing - also, take a paper towel and wipe the dipstick off on it - if you get dark rings around the edge of the oil, or it is dark all the way through, you need to change it - the oil should be clean and without deposits
06-17-2008, 12:47 PM
I like the thorough going-over my car gets from my mechanic at each 3K oil change. They know the car and are quick to note changes that I may have missed. I stopped doing my own oil changes 5-6 years ago - the money saved was not worth the time, mess (particularly with this car!), and that whole oil disposal problem. I have a trusted mechanic who I now see every 3-6 months. I think the car is in better shape for it. Kinda like scheduling a cleaning at the dentist. And the cost is miniscule ~$50 if nothing else needs attention.
False economy is the deadly enemy of aging Porsches!
False economy is the deadly enemy of aging Porsches!
06-17-2008, 02:12 PM
The article on the myth of the 3000 mile oil change is right on target. Flash also stated it very accurately. To build on what he said, the problem with oils is water! Water vapor simply from the atmosphere will condense in your oil pan if the car just sits. This is normally not an issue for a car that is driven simply because oil temps during driving get high enough to drive out any moisture. If the moisture is allow to remain in your oil pan, where it will go to the bottom of the pan, there is the possibility of of it mixing with sulphur that is a byproduct of combusion (and which gets into the oil through blowby around your piston rings).
You also can get water into your oil from just running the car since water is a byproduct of the combustion of gasoline. That water in the form of a hot gas will blow by your rings also, and then condense out in your pan when the temperature of the oil drops below the boiling pont of water.
Again, this is not particularly an issue since the water is never allowed to concentrate. Every time you get the engine hot from driving, you will boil off that water.
On a car that sits, the moisture that has gotten into the system will not boil off and then will mix with any sulphur compounds that have blown by the rings to form sulphurous acid, which will corrode things.
The only way to prevent this is to run the car a lot or to change the oil out on a time schedule rather than to a mileage schedule.
I'm not certain what the optimum time is, but have used once a year as the schedule for my cars. So, since I only put about 2000 miles on my cars each year, I change the oil at the 12 month mark religeously.
As to the quality of oils, your cars oil will not deteriorate. What does deteriorate is the additive package that was put into the oil. For instance, when Mobil first introduced Mobil 1 to the public, their marketing press stated that you could run your cars for 25,000 miles without the need to change the oil. That is because the synthetics do not have parrafins (wax) in their formula and they have enhanced additive packages. The auto companies challenged that statement by threatening to void engine warranties if the oil wasn't changed regularly at their prescribed intervals. Mobil backed down and removed that advertising from the public.
You also can get water into your oil from just running the car since water is a byproduct of the combustion of gasoline. That water in the form of a hot gas will blow by your rings also, and then condense out in your pan when the temperature of the oil drops below the boiling pont of water.
Again, this is not particularly an issue since the water is never allowed to concentrate. Every time you get the engine hot from driving, you will boil off that water.
On a car that sits, the moisture that has gotten into the system will not boil off and then will mix with any sulphur compounds that have blown by the rings to form sulphurous acid, which will corrode things.
The only way to prevent this is to run the car a lot or to change the oil out on a time schedule rather than to a mileage schedule.
I'm not certain what the optimum time is, but have used once a year as the schedule for my cars. So, since I only put about 2000 miles on my cars each year, I change the oil at the 12 month mark religeously.
As to the quality of oils, your cars oil will not deteriorate. What does deteriorate is the additive package that was put into the oil. For instance, when Mobil first introduced Mobil 1 to the public, their marketing press stated that you could run your cars for 25,000 miles without the need to change the oil. That is because the synthetics do not have parrafins (wax) in their formula and they have enhanced additive packages. The auto companies challenged that statement by threatening to void engine warranties if the oil wasn't changed regularly at their prescribed intervals. Mobil backed down and removed that advertising from the public.
06-17-2008, 05:08 PM
Interesting stuff. My ML350 takes seven quarts of oil and the manufacturer recommends changing the oil every 13,000 miles or 12 months which ever comes first. I drive it less than 8000 miles/year and when I had it serviced the oil was still gold colored. My 968 hasn't even been started since January so I guess this weekend I'd better charge the battery, fir it up, and change the oil. <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />
06-17-2008, 09:14 PM
[quote name='BigL2U' post='54924' date='Jun 17 2008, 01:08 PM']Interesting stuff. My ML350 takes seven quarts of oil and the manufacturer recommends changing the oil every 13,000 miles or 12 months which ever comes first. I drive it less than 8000 miles/year and when I had it serviced the oil was still gold colored. My 968 hasn't even been started since January so I guess this weekend I'd better charge the battery, fir it up, and change the oil. <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />[/quote]
Might as well take her for a drive. Summer is right around the corner.
Might as well take her for a drive. Summer is right around the corner.
06-17-2008, 09:20 PM
The diagnostic system on BMWs allows, depending on how you drive, 15,000 - 25,000 miles between changes! While 3000 miles is excessive for most people, I would never go 15K+. I do mine once a year, which equates to about every 4000 miles, with synthetic (currently running Redline 10W40).
06-17-2008, 09:25 PM
I don mine every 4500 to 5000.
I have been using royal purple @ $8 a quart <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />
I have been using royal purple @ $8 a quart <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />
06-17-2008, 10:40 PM
[quote name='rxter' post='54932' date='Jun 17 2008, 05:14 PM']Might as well take her for a drive. Summer is right around the corner.[/quote]
Well, technically, yeah. About 5 more days, but here in the SW, it's been Summer for a good 2 - 3 months now!
Well, technically, yeah. About 5 more days, but here in the SW, it's been Summer for a good 2 - 3 months now!
06-18-2008, 01:33 AM
lol - ok - i'm confused - how does gaineseville florida qualify as the southwest?
06-18-2008, 03:04 AM
[quote name='flash' post='54958' date='Jun 17 2008, 09:33 PM']lol - ok - i'm confused - how does gaineseville florida qualify as the southwest?[/quote]
SIERRA VISTA, AZ/Gainesville, FL... Hail from FL, in AZ courtesy of Uncle Sam.
Three weeks to Fort Benning! Can't friggin' wait to get out of AZ.
SIERRA VISTA, AZ/Gainesville, FL... Hail from FL, in AZ courtesy of Uncle Sam.
Three weeks to Fort Benning! Can't friggin' wait to get out of AZ.
06-18-2008, 01:28 PM
You have some issue with 110 degree days, J.C.?
Tom
Tom
06-18-2008, 02:04 PM
JC - are you actually saying you prefer summer in Columbus to Huachucha? That ain't no dry heat!
06-18-2008, 03:59 PM
Tom and Ralph...
Yeah, well since I'm from Florida, I am used to the humidity, I guess. I'd rather have to take a couple of showers in a day than get bloody noses and cracked elbows and heels from the lack of moisture...
No offense to anyone from AZ... <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />
Yeah, well since I'm from Florida, I am used to the humidity, I guess. I'd rather have to take a couple of showers in a day than get bloody noses and cracked elbows and heels from the lack of moisture...
No offense to anyone from AZ... <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />
06-18-2008, 07:15 PM
you really don't want me to chime in on this and tell you that I put a quarter milllion miles on my 944, with non-syn oil mind you, and if I changed it more than 10 times during that span of time ( 18+yrs ) and miles, it would have been by mistake that I remembered to do so.. <img src="/forum/images/smilies/968/tongue.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/laugh.gif" class="smilie" alt="" /> Yet, as I sold it the engine still ran strong and smooth, without a single problem, no compression loss, nothing ! <img src="/forum/images/smilies/968/dry.gif" class="smilie" alt="" /> so the 3,000 mile myth for me is more like a 30,000 miles myth, and I don't even buy that ; it may be based simply on a single personal experience and not debating the logically sound arguments behind the demerits of "dirty oil", but that's just my m.o. on this topic <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" />
I might change the oil ( using Amsoil Euro 5-40 ) in the 968 every 12- 15k miles... provided I remember... but certainly won't lose sleep at night if I miss that mark by a few thou. miles <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />
I might change the oil ( using Amsoil Euro 5-40 ) in the 968 every 12- 15k miles... provided I remember... but certainly won't lose sleep at night if I miss that mark by a few thou. miles <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />