When my DET was first installed I changed the oil (Valvoline 5w-30) after 500 miles. I then changed it with 10w40 Castrol GTX and I have about 2200 miles so far. I have noticed that my oil pressures have not been as stable as they used to be.

Example: at 3500rpm's, PSI is at 50+. Now at 3500rpm's, PSI is at 35-40. It doesn't get above 50psi even at 5000rpms!!! I'm thinking that the oil is getting contaminated with gas/etc and is losing it's properties. Idle psi has been ok. FYI, I have been using stock oil filters.

Currently have: Autometer elec. Oil guage.

Comments? Suggestions?

I've noticed that when the oil gets old and starts to break down, the oil pressure seems to drop a bit. The new mobil 1 4th gen. stuff is great! I HAD to change the 3rd. gen stuff by 3k miles. With this new formula oil, I changed it at around 2.5k and it still looked almost new and the oil pressures had been stable.

I've been using mobil 1 since around 9k miles (now around 80k). The 2nd gen. stuff was good, the 3rd gen stuff wasn't so good, this 4th gen stuff is the best!

Khiem

oh, 5w-30 by the way, even with the turbo.

det...15w/50.....I change every 5k miles....synthetic mobil1

i dont have a det yet BUT i use the redtop mobil1 sythetic performance driving formula and change it early every time ~ 2500 miles....i have been very pleased with it and it doesnt seem to be too dirty when i change it. Ive used it for about 10000 miles now. Thats just my 2 cents