I now have 40,000 miles on my dmax and I love it. I have the edge box, banks monster exhaust, k&n filter kit. Up until now, I never was one to watch oil pressure guage, however, when I bought the pricey dmax, my habits have changed.


I constantly watch rpm, oil pressure, egt's, etc. Recently I noticed that when I'm cruising at 60-65, my oil pressure is somewhere around 50-55 psi. When I've watched it in the past, it's always been around 60+.


I do have the kennedy oil bypass kit on the truck. But that was installed at 30,000. decrease in pressure didn't start until 38,000 miles.


I wondering if anybody else has noticed this decrease. Is this normal? What are you guys running for pressure when the motor is totally warmed up running down the road? Is this something I should get checked out? Or am I just paranoid?

Mine dropped from the oilguard bypass system. Synthetic makes it drop too. 5wt delvac made mine drop 15lbs.

Mine dropped from the oilguard bypass system. Synthetic makes it drop too. 5wt delvac made mine drop 15lbs.


You do keep things humorus here PC but you should be a bit more careful/considerate. There are folks on here who really don't know much about engines or mechanics. They may believe you're serious when you post stuff like this.Edited by: Oldman

TommJr


I have an OilGuard Bypass running with 5w40 Synthetic. Oil pressure runs 60-65 psi at 65-70mph with 24kmiles on my 03. I also measured the same pressure before and after the OilGuard Install (http://community.webshots.com/album/65003591xTSYrR) (6kmiles) with a mechanical gauge plumbed to the 3/8NPT port on the bottom of the oil filter adapter and found no difference (before/after) in oil pressure. The mechanical gauge also agreed with the OEM gauge.


Have you checked for signs of fuel in the oil. Hopefully this is not the problem, but a leaking injector of return line can dillute the oil with fuel and cause the oil pressre to drop.


If the oil looks ok you could plumb in a mechanical gauge to verify that the OEM gauge is accurate. Then go form there.


http://www.dieselplace.com/forum/smileys/Geek.gifEdited by: jbplock

I have a brand new LLY (200 mi.) and my idle pressure isn't much above red line. Is this "normal"? My 7.4L six year old gasser is higher at idle.

Thanks.

One of the first things I noticed when I picked up my new LLY was that the oil pressure was lower than with my LB7. The LLY is also just a bit louder when the Pilot Injection drops off. It seems to drop off earier too and I could swear I lose power everytime that the Pilot Injection stops.


I love the high Idle, smooth power, and less down shifting than the LB7. It's cool to hear that Turbo ALL the time too.


One more thing, the Allison must be at least 50* cooler for the 2004.5 than my 2002!

One more thing, the Allison must be at least 50* cooler for the 2004.5 than my 2002!





CrincoMax


Please 'splain 50* cooler.

Freddyo,


Mine idles at a tad below 30PSI in gear, and I believe this is "normal idle" oil pressure for these engines. I say this as I have been driving a company truck and my truck both 04's and the oil pressure is identical to one another. I believe for the older dmaxes that minimum idle pressure was around 17 PSI if I recall correctly, and would assume it's about the same for ours. One thing to remember, when at idle there is no load on the engine so not much oil pressure is needed to lubricate the parts, but once the RPM'S come up the pressure should rise immediately to provide adaquate pressure and lubrication for the engine. I am sure if someone has the actual numbers of what minimum oil pressure is for these new 04 engines they will chime in.


Just my .02 Fran

There used to be a rule of thumb that a high performance engine should have 10 PSI oil pressure for every 1000 RPM. Of course this has nothing to do with volume and that is what pumps pump. (GPM not PSI) Pressure should not change much if any because of changing oil brands or by installing a by pass filter. The pump should be sized large enough to compensate for that and normal engine clearance increases. Later! Frank

My LLY idles at 30PSI hot. I'll look today for what it pushes at 1000,1500,2000,2500,3000.

My LLY ildes @30# (hot) and shows 55# @1600 rpm (hot).Edited by: realbigfoot

[QUOTE From Frank Blum]


There used to be a rule of thumb that a high performance engine should have 10 PSI oil pressure for every 1000 RPM.


Yes, I agree Frank you are correct!!!!!


Does anyone know what the hot idle PSI minimum pressure is for the 04 LLY? Just curious. Fran

checked my friend's truck today. He has same year and mods I have. Trucks have identical presuure throughout rpm levels.


Sorry for the hassle. Everything fine here.


Thanks for all the input.