Sorry, here is one more new Duramax owner. May question is about oil pressure. Today, I was trying to get to the 500 mile mark! I noticed at normal engine temp, may oil pressure was running between 50-60 psi at about 60 miles per hour. I was later pulling a grade at about 7000 feet and running about 45 miles per hour and almost grapped my pants when I saw 40 psi on the dash mounted oil pressure gauge. At 60 mph, everything was back at about 60 psi.

Obviously, I am running the OEM oil that GM puts in these things from the factory.

Should I be concerned?

I am not concerned about oil manufacture preferance at this time. I have been reading on that for hours and in my now confused state of mind, will deal with oil itself at a later date.

Thanks in advance!

Mine does the same thing. When the engine is cold or at highway speeds i run about 60 p.s.i. but when crusing around slower it drops to 30-40 p.s.i. ---16,000 miles now no problems--- i am using mobil delvac 5-40. I believe what your seeing is normal.

It's an LLY thing. LB7 put out a lot more pressure in all ranges, but apparently GM lowered the pressure considerably for the LLY's. We all have low oil pressures with the LLY.

Good, I am not the only one that had the concern...the dealer told me that the lower oil pressure was normal...now that the forum experts have agreed....I feel better....

Thanks for the responses! I will drive it until it will drive no more!

The 03 LB7 runs with the lower pressure. Apparently the 01-02 had a higher oil press. I talked to the service advisor about it and he said they had changed the oil pressure and may possibly drop it more on the newer models. He said the engineers have determined that the lower pressure and looser clearances run better in these engines. I can, from experience, believe that may be true.

Tom Cobb

Thanks for the responses! I will drive it until it will drive no more!
That will be a very long time from now!! :exactly:

Same prob here, I am also a new Diesel user and was sorta startled by the low idle oil pressure. Im at 500 miles just as of yesterday. Thanks GM discount!!

Try a quart of Lucas Oil Stabilizer (most truck stops $20 a gallon) I tow heavy almost everyday and the oil pressure will tank pretty quick in the summer. This stuff really works I've used it for 3 yrs and about 280,000mi, no problems, and oil pressure to please the Gods year round!

My duramax has 500 miles on it, Im hearing sort of a click click coming from the drivers side of the engine, should I be concerned about this?

It is a ticking noise that is common to the DMax since the first ones built. Mine went away after a few thousand miles, either that or I just don't hear it since I got used to it. It is nothing to be concerned about. I am on my 2nd truck and have not had any problem related to it.

Tom Cobb

Mine does the same, gm quoted these specs. idle = 98 kpa (14 psi) 1800 rpm 294 kps (43 psi) seems low to me.

GM said ticking noise due to air bubbles in oil mine will tick after oil change and slowly go away

The oil pressure itself is not lower but the reading is. Starting with the 03 model year the oil pressure is no longer direct to the cluster.The oil sender is pcm/bcm monitored and then transmitted by serial data to the instrument cluster. The measured oil pressure is higher than the actual displayed pressure. Don't be alarmed Tim

I was later pulling a grade at about 7000 feet and running about 45 miles per hour and almost grapped my pants when I saw 40 psi on the dash mounted oil pressure gauge. At 60 mph, everything was back at about 60 psi.

You should check by RPM and not mph.

At idle about 2lb per every 100 rpm is a safe min.

At speed most everyone is seeing about 55-60 at 2000 rpm

If you wee doing 45 mph and were still in a high gear the rpm's may of dropped to 1,500 or so and thats why you had the lower oil pressure.

DD

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Glad to see all the responses. Just got my Dmax about a week ago and also noticed the low oil pressure at times. Was about to call the dealer, but decided to logon instead. Boy, I sure am glad I finally got my Dmax!!!! Yeeeaaaaaaa-Haaaaawwwww!

I was worried about the low oil pressure too. It runs about 60psi when it's cold and then drops. I'm glad to hear everybody else has the same thing going on. Yeah, thanks to GM for the deals.

Had a 2004.5 lly new loaner for 4 months. Now have a 2005 lly with 4K miles on it. I put about 3K on the loaner. Both read about 60 psi running, and a little below 30 psi at idle. Definately normal. these trucks, lots of power and 20 MPG at 65 MPH empty.

05' lly with 1400 miles. i have noticed the lower oil pressures also and for the first time the other day heard the 'tick' which i had read about before. had a glow plug light problem(would stay on 25 seconds) but they seem to have fixed that. like my truck so far. gonna make my first pull this week, 6000lb trailer.

89 miles here, I am relieved to read the "low" oil pressure reading is normal.

What a monster truck. I love it.


PJ


05 GMC 2500