My dad told me that since I have Mobil 1 in my car, (he has to use the same in his Vette) that I was good for 10,000km between oil changes. Is this true, or should I still do it at 8,000? Its been 9,500km since my last change, but the oil still looks good. Not overly dark, etc. I don't drive the car overly hard, but as soon as I'm within about 1,000km of an upcoming change, the tach never goes above 4,000 rpm.

So, is my oil ok for 10,000km, or should I change at the reccomended 8?

 

Changing it too soon can't really hurt anything, but too late can. I don't know how long synthetic can last, but I change mine at 3000 miles, or about 5000km.

 

In theory synthetic can last ALOT longer that that. I've heard it can go indefinatly but I'm not sure the validity of that, and I'm not sure what Mazda's warranty department would think of that also. Anyway I'd just go fot the 10,000km. But as stated before 8,00km won't hurt anything.

 

If you really want to push it to the edge.

There are places where you can get an oil analysis test kit.
You would take a sample at your next oil change and mail it
to them. Then they can tell you if you are changing it too late
or if its still good.

 

The *oil itself* may theoretically last that long, but this is not the problem- you need to worry about the other stuff IN the oil, i.e. fuel contamination and small particles of crud too small to be picked up in the oil filter. I've been told that most of the newer studies of synthetic oil do NOT recommend extending the service interval past the car manufacturer's standard recommendations.

 

Yeah, carguy's partly right. The oils's polymers may still be holding up after 10k, but it will be comtaminated and the filter clogged up and likely in bypass. 10k on an oil change isn't a bad thing, you just need to swap for a new filter a few times in between changes. I've always changed filters about every 4k miles and change oil about every 12k. I've had several cars go over 300k with no oil related problems, and original rings, bearings and guides.

A qt. of syn is about $6 and a fiter $5. It's cheaper to change filters than oil. Also, never put addatives in syn oil, that ruins it.

 

As I've said many times on this forum, we have oil change interval for Proteges 15,000km with synthetic oil, new Mazda6 has 20,000km. And driving conditions are pretty lousy, -30C ... +30C so it's quite cold in winter and warm enough in summer. With a good, synthetic oil it's safe to drive 10,000km so I bet your dad is right.

 

I'd say listen to carguy... yes you can go longer, but i wouldnt recommend pusing the limits... spen the little money now on oil change and make your engine last longer. 10k doenst sound too bad.... for an interval.

 

You change your oil because its dirty, not because its "worn out". It will be filthy by 10K, I would change it earlier.

Oh, your in Canada, land of Pot and Hockey...so whats 10K there...about 4500 miles here?

Sure, you can go 10K no problem.

 

10000 km is about 6200 miles, which is twice the conventional service interval for non-synthetic oils.

You don't want bits of dirt that make it through the air filter in your engine longer than necessary. They're supposed to get washed away by the oil and trapped in the filter, but it stands to reason that more dirt means more chances for a few particles to get through.

Also, moisture mixes with oil to make it sludgy, and that is bad. I'm guessing this isn't as much of a problem with synthetic oil, but it probably happens to some degree. This is especially a problem if you make lots of short trips, because the engine doesn't get a chance to warm up and evaporate the moisture that builds up in the crank case.

It's not that expensive to change oil yourself, and it's kind of fun to do, so I change my synthetic every 3000-4000 miles (5000km or so). Like the earlier posts said, it can't hurt. Overmaintained cars are not the ones you see broken down by the side of the road or in the junk yard after five years.