# Oil changes. **URL:** \ **Category:** Factual Questions\ **Created:** [June 11, 2015, 5:17pm UTC](https://boards.straightdope.com/t/oil-changes/722269 "2015-06-11T17:17:39Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [June 12, 2015, 4:59pm UTC](https://boards.straightdope.com/t/oil-changes/722269/21 "2015-06-12T16:59:46Z")
> [@Really\_Not\_All\_That\_Bright](#): > > The Tire Kingdom by me does full synthetic for $50. I don’t really understand why the OP needs synthetic oil given how little he drives, though. Mercedes specifies that you must use full synthetic oil in their engines. (several other car makers do also BTW) ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [June 12, 2015, 4:59pm UTC](https://boards.straightdope.com/t/oil-changes/722269/22 "2015-06-12T16:59:57Z")
> [@Gary\_T](#): > > If it’s a Mercedes it requires European spec oil, and if it’s a later model Mercedes it probably requires synthetic oil. That may seem unnecessary from a common-sense standpoint, but it is necessary to preserve the engine warranty. Saving a hundred bucks a year may not be the wisest approach here. > > My question is, where are you going that only charges $125 for a Mercedes oil and filter change? 😉 Well, if it’s an A service, it’s closer to $300. If it’s a B service, it’s closer to $600. When it’s neither, an LOF is about $125. Why? Because AMG. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [June 12, 2015, 5:13pm UTC](https://boards.straightdope.com/t/oil-changes/722269/23 "2015-06-12T17:13:52Z")
n/m ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [June 12, 2015, 5:22pm UTC](https://boards.straightdope.com/t/oil-changes/722269/24 "2015-06-12T17:22:02Z")
> [@Gary\_T](#): > > If it’s a Mercedes it requires European spec oil, and if it’s a later model Mercedes it probably requires synthetic oil. That may seem unnecessary from a common-sense standpoint, but it is necessary to preserve the engine warranty. Saving a hundred bucks a year may not be the wisest approach here. > [@Rick](#): > > Mercedes specifies that you must use full synthetic oil in their engines. > (several other car makers do also BTW) Ah, thanks. ---
**Author:** ![commasense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/commasense/32/3017_2.png) [@commasense](https://boards.straightdope.com/u/commasense)\ **Post date:** [June 12, 2015, 5:27pm UTC](https://boards.straightdope.com/t/oil-changes/722269/25 "2015-06-12T17:27:48Z")
> [@QuickSilver](#): > > Why? Because AMG. Which model? And where do you live? If it’s one of [these](http://www.mbusa.com/mercedes/legacy/vehicles/class?class=SLS&bodystyle=CPE), I’ll be happy to stop by every few weeks to take it out for a spin and heat up that oil for you! Just so you’re not wasting money on that annual oil change. 😃 ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [June 12, 2015, 5:31pm UTC](https://boards.straightdope.com/t/oil-changes/722269/26 "2015-06-12T17:31:09Z")
> [@Chefguy](#): > > If it’s a drop-off service and not an appointment, you go to the end of the line. Someone above mentioned $29 for an oil change. I’d like to know where you can get a synth oil change that cheap. My local Toyota dealer charges me $29.99 to change my oil and filter for my 2010 Toyota Tundra 5.7L V-8 with synthetic oil. I didn’t ask for synthetic oil, it came with it and they said not to switch it out. They run a special every 6 months, which happens to be about when I need to change my oil. I doubt they make any money at that price, but it gets me into the dealership looking at new trucks. They’re not stupid. I live in Montana, if that matters. ---
**Author:** ![Dibbs](https://avatars.discourse-cdn.com/v4/letter/d/da6949/32.png) [@Dibbs](https://boards.straightdope.com/u/Dibbs)\ **Post date:** [June 12, 2015, 5:40pm UTC](https://boards.straightdope.com/t/oil-changes/722269/27 "2015-06-12T17:40:29Z")
If the car is getting so few miles on it, I would think you could easily go at least two-years before tossing it out. There’s no point in throwing away good oil, time and money. ---
**Author:** ![Lanzy](https://avatars.discourse-cdn.com/v4/letter/l/74df32/32.png) [@Lanzy](https://boards.straightdope.com/u/Lanzy)\ **Post date:** [June 12, 2015, 6:00pm UTC](https://boards.straightdope.com/t/oil-changes/722269/28 "2015-06-12T18:00:26Z")
My car recommends changing oil between 12-18000 miles, but if it is driven less than that then at least once every 2 years. The car does remind me when it is time to change the oil based on something it is testing while it is running. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [June 12, 2015, 6:25pm UTC](https://boards.straightdope.com/t/oil-changes/722269/29 "2015-06-12T18:25:05Z")
I know that recommended is every 10,000 miles after the initial change at 5,000. Else, once every year. The car keeps track of the state of the oil and when it was last changed. That said, since I don’t drive 10K in a year, I wondered whether breakdown of oil is a real issue or if this is just something the manufacturer recommends to err on the side of caution. The service guy seemed fairly earnest in cautioning me about an upcoming oil change when I was in to get the state inspection done. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [June 12, 2015, 6:36pm UTC](https://boards.straightdope.com/t/oil-changes/722269/30 "2015-06-12T18:36:32Z")
> [@QuickSilver](#): > > The car is driven weekly but relatively short trips. 5-10 miles. Weekly totals are 25-50 miles. The engine always comes up to operating temp so I’m not sure there is cause for worry about condensation buildup. It doesn’t just need to come up to operating temp, it needs to stay there for a while. It’s analogous to bringing a pot of water and then shutting off the heat, instead of leaving the heat on until the water boils away. I suspect your owner’s manual gives two change intervals - one for “normal” duty, and one for “harsh” duty (the latter of which includes short trips and/or cold weather, both of which inhibit the full drying-out of the oil). My own manual (for a G37) indicates 7500 miles for normal duty and 3750 for harsh duty. 2000 miles isn’t a lot less than that lower limit, especially after a year’s time. > [@Dallas Jones](#): > > Moisture can condense out of the air and into the oil. Just so we’re clear, we’re not just talking about a little dew settling out of your garage air on a cool evening. The moisture in the oil comes from the combustion process itself. When you burn a hydrocarbon, one of the exhaust products is water: burn a gallon of gasoline, you create about a gallon of water. In a hot engine, the piston rings are sealing well and virtually all of that exhaust gas goes out the tailpipe. But when the engine is cold, the piston rings aren’t sealing perfectly, and some of the exhaust escapes into the crankcase, creating condensation that settles into the oil. The gasoline also doesn’t vaporize completely, so you also get raw hydrocarbons escaping into the oil. The oil has additives to deal with these things, but only in limited amounts; after a large number of cold-starts, those additives don’t have much left to give. ---
**Author:** ![carnut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnut/32/3531_2.png) [@carnut](https://boards.straightdope.com/u/carnut)\ **Post date:** [June 12, 2015, 6:57pm UTC](https://boards.straightdope.com/t/oil-changes/722269/31 "2015-06-12T18:57:57Z")
> [@QuickSilver](#): > > The car is driven weekly but relatively short trips. 5-10 miles. Weekly totals are 25-50 miles. The engine always comes up to operating temp so I’m not sure there is cause for worry about condensation buildup. > > Oil/filter changes run $125. Not prohibitive and certainly not something worth skimping on. I simply was wondering if actual breakdown of the oil occurs or not for a car operating under relatively regular intervals but low mileage use. > > No down side to changing it yearly. I’ll just continue to do that. Once each month or two, you should stretch your car’s legs and go on a small roadtrip to warm your engine up properly - absolute minimum 30 minutes driving before turning the engine off again. As for synthetic oil, don’t bother with so few miles. That’s excessive to your need IMO. It will save money to switch and won’t harm the engine - unless it is a super-special engine that needs to be handled with kid gloves. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [June 12, 2015, 7:16pm UTC](https://boards.straightdope.com/t/oil-changes/722269/32 "2015-06-12T19:16:56Z")
Thanks, **Machine Elf**. That’s an explanation I can understand. **Carnut** - yeah, it gets a regular workout like the one you’re describing. As to the synthetic oil, the car comes from the factory with it. MB recommends it. And the engines are hand built by one of 50 engineers in Affalterbach for these lines of cars. So ‘kid gloves’ isn’t far from the truth. It’s a bit special. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [June 12, 2015, 8:43pm UTC](https://boards.straightdope.com/t/oil-changes/722269/33 "2015-06-12T20:43:10Z")
The science behind what you actually need is hard to track down. The guys I know who actually study tribology told me they just follow the manual and use some synthetic oil I promptly forgot. Mobil something. I was hoping they analyzed it regularly ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [June 12, 2015, 9:09pm UTC](https://boards.straightdope.com/t/oil-changes/722269/34 "2015-06-12T21:09:22Z")
> [@carnut](#): > > As for synthetic oil, don’t bother with so few miles. That’s excessive to your need IMO. It will save money to switch and won’t harm the engine - unless it is a super-special engine that needs to be handled with kid gloves. So if he chooses not to use synthetic oil, based on your recommendation, despite the car makers requirement for synthetic, are you paying for his engine repair? :dubious: ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [June 12, 2015, 9:14pm UTC](https://boards.straightdope.com/t/oil-changes/722269/35 "2015-06-12T21:14:13Z")
> [@Ruken](#): > > The science behind what you actually need is hard to track down. The guys I know who actually study tribology told me they just follow the manual and use some synthetic oil I promptly forgot. Mobil something. > > I was hoping they analyzed it regularly There’s a company called [Blackstone Labs](http://www.blackstone-labs.com/) that’ll analyze the condition of your oil if you send them a sample. Usually people just do it out of curiosity, but I suppose on a car like this with really expensive oil changes it might be worth $25 to see if you can stretch it a little longer. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [June 13, 2015, 12:06pm UTC](https://boards.straightdope.com/t/oil-changes/722269/36 "2015-06-13T12:06:33Z")
Thanks for the link, **Greasy Jack**. I was aware that you could get your oil analyzed for various things. Since I don’t track the car or put a lot of miles on it, I didn’t think it was worth the bother. I might do that though, just out of curiousity. But again, with so few miles year to year, it surprised me when the tech said the oil breaks down anyway. I just wondered why, thinking it was a relatively well sealed system. **Machine Elf** ’s explanations seems reasonable and once a year oil changes aren’t exactly a hardship either. Thanks everybody. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [June 13, 2015, 2:25pm UTC](https://boards.straightdope.com/t/oil-changes/722269/37 "2015-06-13T14:25:30Z")
It’s probably something you could check once at the recommended test time, T, then again at 1.5T, 2T, etc. Once you have an idea of actual decomposition, you can make your own schedule. ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [June 13, 2015, 2:59pm UTC](https://boards.straightdope.com/t/oil-changes/722269/38 "2015-06-13T14:59:29Z")
Ordered the kits. What the heck, might as well check the other cars while I’m at it. 🙂 ---
**Author:** ![Morgenstern](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@Morgenstern](https://boards.straightdope.com/u/Morgenstern)\ **Post date:** [June 13, 2015, 3:17pm UTC](https://boards.straightdope.com/t/oil-changes/722269/39 "2015-06-13T15:17:13Z")
I have a Mustang convertible that probably gets 2000 miles a year on it. The oil monitor message appears once a year, almost to the week, and tells me the car needs an oil change. It’s a synthetic blend of oil. So my guess is that once a year is the minimum if the mileage limit isn’t reached. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [June 13, 2015, 4:50pm UTC](https://boards.straightdope.com/t/oil-changes/722269/40 "2015-06-13T16:50:08Z")
> [@Morgenstern](#): > > I have a Mustang convertible that probably gets 2000 miles a year on it. The oil monitor message appears once a year, almost to the week, and tells me the car needs an oil change. It’s a synthetic blend of oil. So my guess is that once a year is the minimum if the mileage limit isn’t reached. Could just be that it’s on a timer. [Previous page](https://boards.straightdope.com/t/oil-changes/722269.md?page=1) [Next page](https://boards.straightdope.com/t/oil-changes/722269.md?page=3)