My general rule of thumb is change it when the car/manual says ~25% life, ~50% if its deep black or smells like gas.

The engine makes all the difference, the J appears to be really easy on the oil and I'm totally happy with what the MID says. Personally I'd change it early so the MID never nags me. Just try and top the oil up to the top dot when you change it, it should never go below halfway before it's changed.

OP: You should swap a 2 cycle motor in. It burns fresh oil all the time, how wonderful.

This stuff is based of many assumptions made over the years, so you know its right.

 

My valvetrain is loud as crap and it drives me crazy. To make matters worse, ever since I had my power steering rack replaced, engine noise is leaking through my driver's side vent.

 

figure that one out

 

Something is hitting the firewall. Broken mount, a loose bracket, etc. take a good look down between the engine and firewall and you'll probably find something. Does it change when it's in drive or reverse?

 

No change whether in gear or not. It's definitely valvetrain noise. Someone suggested it might be the collar around the steering shaft as it goes through the firewall. I asked the dealership to check out the collar when the repaired 3rd gear and they said everything appears fine.

 

ok, I have an 04 tl that has a terrible engine noise that only smooths out at 2000 rpm. as soon as it returns to idle sound returns. sound appears to be coming from passenger rear side of engine but cannot pinpoint, in attempt to fix I have replaced two power steering pumps an ac pump and still have this diesel truck sound. ? can I run engine with drive / power steerig /ac pump belt off to eliminate noise culprits?? PLEASE HELP am at the end of my rope here ........

 

Our '08 TL base is and has been quiet from day 1. I change the oil every 5K even though the oil life indicator says it has 45-50% left. I do it mainly because I don't run synthetic oil and I don't feel comfortable leaving that small oil filter on for more than 5K.