I know that oil is not the part to save money on, but still...
What is the optimal oil change interval when commuting on freeways 10.000miles in 4months, synthetic Mobil1 10W-40?
Is it bad to change oil at e.g. 13-15.000mi instead?
On a '95, you are taking your life in your hands going to 10K!!! The m111 motor in your car should not go over 5K between oil changes. Really, no car should go between 5K for an oil change, but yours in particular. The motor was not designed with such long service intervals in mind. These were thought up by marketing departments that understand very little about what needs to be done to assure longevity in a motor.
I note Phaedrus242 reply. I would agree with his comment re oil changes on many older ie. 95 or earlier vehicles. The problem here is that the use of synthetic motor oil presumably allows longer periods between oil changes ergo, the late model C230s (mine being 2003), which require changes every 15,000KMs(Canada), US would be 7500 miles. I always changed my auto's oil as close to 3/4000 miles ie. my last auto which was a 300E. We old guys remind ourselves that if you didnt change the oil every 3000 miles you had better add some or the red light would start blinking!! I don't know for sure but I suspect that the C230 has synthetic transmission oil as well and, the book does not suggest changing the oil for the first 50K miles or so. What to do gents when we are supposed to follow our warrantee specs?
Thanks for your replies. Guess you want to replace your gear box oil.
My service manual also states intevals on 15.000km, why 12000km (7500mi) in the US - I mean, Mobil1 is from Exxon.
Since my car is not driven in city traffic at all, but coninuous about 90-100km/h, I thought the oil would "last longer". One other thing is that it does not consume or leak any oil, so it looks good.
But what has happened in the engine technology which would explain longer service intervals on newer cars?
The longest I've seen is Honda with 40.000km! BMW 20-30.000km. New MB between 15-30.000km depending on driving style etc.
In my opinion, nothing has happened in engine technology. Oil filters have come a long way as has oil, but an oil change will always be cheaper than a new motor. In my former RX7tt, oil changes were religious at 2000miles with Motul synthetic rotary oil (big$$$). I've worked on around repair facilities long enough to know not to believe the marketing hype these companies are trying to feed us. What good does it do them if your engine goes 300K because of proper fluid maintenence?
For my 2004 CLK320, I like to change oil more often but I am getting conflicting responses from different sources.
I was told that FSS (Flexible Service Schedule) checked the quality of the oil and determined the service interval. If I changed the oil too often, this would screw up (prolong) the schedule for other components.
I like to change the oil at half the MB recommended interval. 15K KM is way too long. I am , however, concerned about the FSS.
The FSS system has indicated oil changes in my '03 C230Sedan at 13k mile intervals. (lots of highway driving)
I was concerned about the high mileage, so I started surfing the web, looking for more information.
I found several people who had similar intervals, and had sent their oil off for analysis. Every example that I could find, showed that the oil was still in good condition, with no problems found, even after 13k miles.
Short version: It appears that there is no problem with the longer intervals on these cars, as the sump is large enough (twice the oil of the typical four-cylinder), the oil runs cool enough, and there is very little blow-by contaminating the oil.
Do your own research to satisfy yourself. Of course, on older cars, I would go by the manufacturer's recommendations.
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