I just purchased an RV with a 2006 Duramax 6.6L engine in it. I watched the mechanic change the oil and when we started the engine it shot up to 80 on the oil pressure gauge (gauge shows 0-80). It came down after about 30 seconds, but creeped down very slowly. It is now around 40, but the gauge fluctuates with the rpm (is that normal?). When I rev the engine up to around 1800 rpm, the oil pressure goes up to 80 and maybe even a little beyond. This is my first Chevy diesel and I was wondering if this is normal or if I should be concerned.

It is probably because the oil is cold. Have you drove it and got it warmed up? Mine doen't usually go that hi, I am around 40-50 psi.

Yes, that's normal... I see 90 on the stock gauge every time it's cold. 30 idle to 65 at anything above idle is about what I see when it's at temp.

What weight oil did he use?

The mechanic used 15W40 oil. I haven't driven it since the oil change...I was a little concerned about the oil pressure. When I originally drove the rig home, it was around 30 at idle and would increase to 60-70 as I accelerated/increased the rpm. I just thought it was odd that it would reach the max pressure on the gauge of 80.

The reason the oil was changed was because the oil light came on the second time I went to drive it. Turns out another mechanic had also just changed the oil, but only put in 10 qts, vice the 14-ish this one requires. Hopefully I didn't do any damage...it was only a 10 mile drive home. Any thoughts?

The mechanic used 15W40 oil. I haven't driven it since the oil change...I was a little concerned about the oil pressure. When I originally drove the rig home, it was around 30 at idle and would increase to 60-70 as I accelerated/increased the rpm. I just thought it was odd that it would reach the max pressure on the gauge of 80.

The reason the oil was changed was because the oil light came on the second time I went to drive it. Turns out another mechanic had also just changed the oil, but only put in 10 qts, vice the 14-ish this one requires. Hopefully I didn't do any damage...it was only a 10 mile drive home. Any thoughts?

:eek: You were approx. 4 qts low on oil. Have you notified the store that changed your oil & let it go 4 qts low? If not, you should as 4 qts low is quite a bit & the oil light came on twice. Also get something in writing from the store that found that the problem was low oil content, make sure it's dated & on their invoice or letter head. Send a oil smpl to a lab. This may give you some idea of damage if any. When you go back to the store that shorted your engine on oil take a ball bat to use on the guys nuts that service your vehicle. Hopefully you will have gotten him prior to his fathering any offspring. By the way your oil pressure is normal for new oil @ the right fill content. Is this an LBZ D-Max?

I just purchased an RV with a 2006 Duramax 6.6L engine in it. I watched the mechanic change the oil and when we started the engine it shot up to 80 on the oil pressure gauge (gauge shows 0-80). It came down after about 30 seconds, but creeped down very slowly. It is now around 40, but the gauge fluctuates with the rpm (is that normal?). When I rev the engine up to around 1800 rpm, the oil pressure goes up to 80 and maybe even a little beyond. This is my first Chevy diesel and I was wondering if this is normal or if I should be concerned.

I am around 45-55 psi on my 07

mine ran high because i was low on oil didn't know diesel burns oil