how much permanent damage was done going 11k miles w/out oil change??
 

ok, firstly, this was NOT on my personal car, and the engine is a 2.8l inline six gasser. I'm wondering how much permanent damage was done, if any(hopefully not), and what kind of maintenance should be done to compensate for this. Also, would switching to synthetic help correct any damage done? and one more question, if you drive mostly highway miles(interstate, constant speed) does that have any effect on how often the oil needs to be changed??
thanks
Ryan

this is asking a question like "how blue is the sky?" As a gasser and mostly highway miles I would say not much happened but keep it up and bad things will come of it.
Change it now, drive it to get good and hot, change it again the same day. This would clean out all the possible junk as much as anything else.

I would say no big deal if you let it go that long once or twice, but if the car had 10K mile oil changes all it's life, I would stay away from it.

Like said, drive the car for about 20 minutes, keep it running while you get your oil changing supplies ready, and as soon as you shut it off, change the oil. That is what I do with my cars, and I really think it makes a difference when you change it hot because all of the bad particles are still suspended in the oil.

permanent damage
 

Serious permanent damage is probably unlikely these engines are designed to take a certain amount of human forgetfulness. Once while hitchiking I was picked up by a large diesel mercedes truck. The truck wasn't running that well and the driver said he had it on the dynamometer (sp?) that morning and it was only putting 147 hp on the ground instead of the 250 the truck was rated for. I asked if he knew the cause. He said it may have something to do with the 160,000 miles on the engine and that he had only changed the oil once in that period. He worked for Mercedes-Benz and the company policy was to abuse and torture the truck to death. then they did an autopsy to determine the cause of death and used that information to redisgn the engine. You should be okay.

permanent damage
 

Serious permanent damage is probably unlikely these engines are designed to take a certain amount of human forgetfulness. Once while hitchiking I was picked up by a large diesel mercedes truck. The truck wasn't running that well and the driver said he had it on the dynamometer (sp?) that morning and it was only putting 147 hp on the ground instead of the 250 the truck was rated for. I asked if he knew the cause. He said it may have something to do with the 160,000 miles on the engine and that he had only changed the oil once in that period. He worked for Mercedes-Benz and the company policy was to abuse and torture the truck to death. then they did an autopsy to determine the cause of death and used that information to redisgn the engine. You should be okay.

I would say almost no chance of damage. Consider that many European manufacturers shifted their recommendation to 7500 mile oil changes during the 1980s, if not even earlier than that. Industrial equipment generally operates for years (decades) on the same oil, it is on a quarterly analysis program and is only changed if the analysis indicates change is needed, just as the filters are changed based on d/p.

The 3000 mile oil change is a preventive measure against contaminants in the oil since most of us are not going to pay for an analysis program. It is insurance against being stranded and paying for expensive engine repairs (though certainly no guarantee of that!). The interval also is quarterly for the average driver, which gets the car to a mechanic at a good interval for checking other common failure items such as belts and hoses. It gets the oil and air filter replaced before they become clogged (or blow).

It may interest the mechanics among you that our company tractors have gone to a 100,000 mile oil change interval, with synthetic oil, high quality air filters and a quarterly analysis. It is believed this will not only save money but also will be environmentally friendly. Probably one consideration here is tractor trucks are not started nearly as often as cars, and their larger crankcases let them idle for extended periods of time.

From what I have heard, the number of starts on the engine really ought to be the determining factor of when to change the oil, but who among us is going to keep a log of every tme we start the engine?