After the continued successful brainwashing by the media that if a car goes one mile over 3k on the same oil it is going to die, Shing, myself, and Jeff92se decided to start getting our oil analyzed at the end of each oil interval to see if "3k is a waste of money".

In the spreadsheet at the bottom of my sig (finally linked through Clubmaxima.com in ZIP format....thanks Peel!). Just right click and save to your disk and extract for your viewing pleasure.

http://forums.clubmaxima.com/files/1...%20Results.zip

The motor oil of 5 cars are analyzed:

Shing's 98 Maxima (twice so far)
Both were around 8k intervals with Mobile 1 oil and Nissan filter

My 99 Maxima
One analysis after 10.4k with ULX-110 (dino oil with a LOT of additives) and Mobil 1 filter

Another analysis after only 1,288 miles on Amsoil with an Amsoil filter just to see the types of additives used compared to ULX-110.

My 94 Maxima
One analysis after 8.5k with ULX-110 and Mobil 1 filter

My dad's 99 Acura TL
One analysis after 12k with Amsoil and Amsoil oil filter

Jeff92se's Maxima
One analysis after 6k with Amsoil and Toyota filter; Jeff has been having coolant loss and oil consumption problems.

All other cars besides Jeff's go high mileage (15k plus per year) and do not have oil consumption problems.

The results speak for themselves. Except for Jeff's Max, all other cars went extended drain intervals with normal wear levels.

Other interesting things that an oil analysis can bring to light:

-- Wife 2.0's 99 Maxima has some sort of air filter problem. Whether it's a leak somewhere or was just a dirty filter is/was unknown. That second sample at 1,288 miles had a high silicon content already, which means dirt is getting by the air filter somehow. No solution yet, but good to know there was an issue with it.

-- Dad's 99 TL had a lot of bearing wear, which is apparently typical of Honda motors (which I didn't know). Also, the K&N air filter hadn't been cleaned in 11k, so it was good to know that a K&N drop-in filter does its job.

-- Shing puts WAY too many miles on his car. He already has another Mobile 1 sample he is sending in with 11k on it. This spreadsheet will be updated when those results are available.

*****
As for the ATF results, it is still a work in progress as well:

-- Nissan ATF lasts NO MORE than 30k. My 99 was tested with 32k on it and it needs replacement.

As for my 94, I'm experimenting. I had my ATF examined after 30k (when I had a flush done by a machine) and it needed replacing as well. I then did 3 drain 'n fills, refilling with Amsoil synthetic instead of plain dino ATF. On the 4th drain n' fill, I took another sample and should have ALL those results on the spreadsheet by next week.
In addition, I am sending off my auto tranny fluid to be analyzed this week (after 30k) and will post those results as well.

In conclusion,

3k is a waste of money.