Is synthetic oil nessasary.Been using regular oil since day one. Change every 3000 miles.No off roading.

Not necessary, but as Doc said, an added buffer. I have been keeping accurate mileage records on my H3 since I got it 4 years ago. I switched to synthetic Mobil 1 two years ago and saw an IMMEDIATE 1 mile per gallon increase, that has been consistent ever since.:D

Thanks for the info gentlemen. I was thinking about it more yesterday and with the type of driving I do, 95% easy highway miles, it plausible I could go this long between changes. The info you posted Doc seems to confirm that.

That being said, guess what I'm doing today ;)

I keep pretty decent records of fluid changes and change our HUMMERs @ 6K regardless of the oil change light or not. If it goes off before the light then it gets changes pretty quickly.

By the way we have been using Synthetic for a while now. As Doc said "buffer"!

BTW, if you have a ScanGuage you can read the Oil Life percent remaining. That might give you more confidence that the Oil Life Monitor is doing its job.

Timely subject. I'm just over 5k since the last oil change on my T and I'm waiting for the Change Oil message. I had guessed it would come up around now, but if 7,500 is more typical then I'm not going to start getting worried for a while. I'm running synthetic so that should give me a bit more buffer as you guys say.

Call me old fashion but for under $20, I will stick with ever 3,000 miles. Its cheap insurance.

Synthetic for under $20? Send me some, thanks.

I was thinking the same thing!;)

Also, I was wondering....'Insurance' from what?? Do you change your trans fluid every 3000 miles also, or do you go by what the owners manual suggests?

it costs me about $50-$60 to change my oil