Ahhhh, what just happened to my oil pressure?

[RSchwarzli]

I always run 45-50 psi at 1500 rpm+. I did an oil change, now I run 35-40. Huh? What just happened? When I first do an oil change it normally is up near 60-70 then drops down. Not this time. Idle even seems low at 25-30.



Only thing I can think of is I am getting to the bottom of a 45 gal drum of oil. Is it possible the oil is thinner?? Thick settles to bottom and now I am in the thin as it is almost all gone???



Am I missing something?? Could it be from warmer air? It is 80 here now.



Help! I leave in 36 hours for Cummins and Dodge (AKA 2000 mile drive)! I dont want to be on the side of the road, again, in another country far from home! :{



Robert





EDIT: Could it be the filter? I was running a stratapore and now a 3349 (they ran out), but then again I normally run a 3349. I have only run the 16035 (is that number right??) once now. Did it clean out the system and now I have less clogged arteries and therefore lower psi?? Yes i am picking at straws but want to give all the info.

 

[HHhuntitall]

Bob, you got an oil pressure guage, or are you going by the factory pressure guage in the dash? Remember, those sending units often get sludge in them and gradually lose pressure. Taking it out and cleaning it, say with carb cleaner, might help. I serously doubt the thinner oil is settled to the bottom of the barrel. It should be the other way around, as thicker oil is heavier, therefore settling lower in the distillation tower..... Additives are a whole other story. But I don't see that much of a difference in the oil viscosity from one oil change to another. FWIW, I go through 3-4 barrels a year, and have never seen either happen.

 

[JLEONARD]

You can try cleaning as suggested, but it also might be simply the wire connection has a bit of corrosion and is changing the resistance hence the reading.

If you are freaking out too much perhaps connect a mechanical gage as a "test gage".

 

[JLandry]

I agree... get a second opinion (pressure gauge) before you go crazy.



Good luck,



John L.

 

[RSchwarzli]

It is an autometer unit.



Good thought. I will pull it tonight and do a cleaning to be sure. Guess I could always throw another spare sender in too as I dont imagine it would be the gauge.

 

[bheiting]

Did you fill the filter with oil before installing the new one? If not, it may be possible to get air trapped, lowering oil pressure. Filling the filter has arguments both for and against on the forums. Cummins suggests you do, just make sure you don't introduce any junk from the seal on the oil container. Over filling the crankcase will cause the crank to whip plenty of air into the oil, lowering oil pressure.

 

[Bob Beauchaine]

Robert



I have been doing a little reseach of my own - prompted by a good freind who lives in upstate NY. He wanted to know about ZDDP (Zinc Dialkyl Dithio Phosphate) an anti wear additive. I did a fair amount of research on this and still don't know if this has effected my sudden drop in oil pressure after my last oil change or not. Since I've done oil analysis at each oil change I started there to run the ZDDP numbers. From 1999 to 2009 I ran an average of 1372 PPM of zinc(recomendations are 1400 PPM) per change. In 2010 the PPM of ZDDP dropped to 1006 PPM.



The original concern was in regards to classic cars. BTW ZDDP had been an anti wear additive in oil for about 70 years before it was banned by the government due to its potential effect on catalyic convertors. It was also recomended for deisel engines made prior to 1996. The link below gives more information thwn there is room for here.



ZDDPlus™ - ZDDP for Classic, Muscle Cars & More



Bob

 

[RSchwarzli]

BH - Yes. Always prefill the fiter.





Bob - Interesting. In my case, its the same oil I have used for 6 years. Possible air lock somewhere in the system as suggested above.



On the drive down to cummins and back it was 50 cold, and 40 warm. Seems about the right spread, just lower. I dont know.