I would say high mileage is a variable number depending on how you drive your car.

If you're me, and already gone through one auto tranny... or Faithofadragon who goes through multiple, it'd be 50,000-70,000+... but if you're a normal driver, or 2Uniq who never shifts above 3,000 RPM's, then I would put high mileage at 80,000-100,000 miles. My car has 114,000 miles and I would consider that high mileage.

 

if you've used synthetic since new then i wouldnt worry about it because it builds up less sludge so you won't have as much of a problem.

 

^ I don't know how anyone could never shift above 3k rpms at least on occasion. It would be impossible to speed up in time to merge into traffic when getting on the highway. At least for the ramps around here.

I'm switching to full synthetic this summer, and I'm at 76k miles.

 

Mobil 1 has been API approved since it came out. They're still approved by MB, Corvette, Porsche. Everything you guys said is basically a myth. If your car still have strong gaskets, using synthetic oil is no problem with older engines. I used to burn a quart every 3,000 miles in my tiburon, now using Mobil 1, I haven't lost a quart yet.

Regardless of the oil, if it's API certified, you can go over 10,000 miles if you don't drive to hard. That Extended Performance shit is plain advertising scheme, it's just like saying premium gas will help your engine, and it really doesn't.

 

I have run mobil 1 since the first oil change after I bought my car new. 122,000 miles and she barely burns a quart between changes at 7500 miles

 

Allow me to clarify:

Mobil 1 does NOT cause leaks, encourage them etc. If used in an un-worn engine (as in the case of Mad-Machine), it will keep the engine in great condition.

The ghosts that haunt this product are from badly neglected engines with worn/ damaged seals. Mobil 1 will NOT fix those problems and will leak just like any other oil. For a fix, go to www.Auto-rx.com for the only product I know that can help with this. Once you peform a full Auto-Rx treatment on a worn engine, you can embrace Synthetic oils once again (as I have).

That being said, Mobil 1 is a great oil, and Extended Performance seems to tweak a decade old formula even further.

I have used MB1 EP for 8000 miles and will now add a quart for the first time since the oil change. Then, I will push it for another 2000 miles before changing the oil.

 

hmm, i ran crap oil forever and im nearing 160k. just about a month after my last cheap $20 oil change i heard a clicking noise which from some help i concluded was probably a lifter. i decided to get off my ass and swith for a full synthetic, and ended up going with mobil 1 10w-30 for the summer time. after running it for a few minutes and parking the car, i awoke the next morning to no more click, and whats more i have had no leaks at all.

 

You would GREATLY benefit from auto-rx. Try it.

 

I use mobil one full synthetic every 3000 miles. I believe that Mitsu requires they use it in every oil change to keep the warrenty.

 

i run mobil proclean 5000 in mine

great oil and cheap too somethin like 1.60 a quart