Drop in Oil Pressure: Changed to Synthetic!

[CBrittan]

Today I changed my oil from Rotella T to Mobil Delvac 1 full synthetic 5w40. I also upgraded my oil filter to Fleetguard 'Stratapore'.



I observe a noticeable drop in oil pressure (as indicated by the guage which I know may or may not actually provide useful information). On Rotella my guage always indicated above the middle (mine is metric so a simple word description should do) whether at idle or at highway speeds when pressure almost reached the 3\4 mark.



Now is see at idle the pressure drops almost to the 1/4 mark (still in the safe zone) and at highway speeds is slightly less that it used to be on Rotella.



I know the debate continues about mineral v\s synthetic and I understand that 5w40 will flow more readily than 15w40. It gets cold here where I live and that's why I made the change. But I am more than surprised to see such movement on my oil pressure guage when before it hardly ever moved.



Anybody have any experience with similar observations, please?

 

[NIsaacs]

I have never used synthetic oil in anything so I am just guessing here. I think the drop in oil pressure is a result of the lighter weight. 15/40 vs 5/40.





"NICK"

 

[amsoilman]

I have never used synthetic oil in anything so I am just guessing here. I think the drop in oil pressure is a result of the lighter weight. 15/40 vs 5/40.





"NICK"

Both of the oils mentioned here are the same Viscosity when the operating temp is reached. (Oil operating temp)



Wayne

 

[nickleinonen]

CBrittan:



are you talking about the factory glorified idoit light gauge? it's just a 6psi pressure switch and the pcm controls the gauge movement to represent what the customer wants to see...



i went from rotella t 15w40 to duron 5w40 synth [base 3 stock iirc?] and the pressures stayed virtually the same on my external oil pressure gauge. at idle from the top of the filter housing, it won't go under 20psi. i may relocate that pickup to where the factory switch is located... [and put a temp sensor there. . ]

 

[RCorbeil]

I have 1355 KM on an 04. 5, also metric, run straight up at 275 on factory fill.



Ron

 

[ssanders60]

Synthetic, lower oil pressure

The synthetic is circulating faster, cooling the engine

at higher rate of proficiency by taking the heat away

from the bearings, especially the turbo bearings.

I've heard mechanics argue that Delo 400 does not

provide oil pressure readings as well as Rotello, therefore

they wouldn't use Delo. The American Oil Institute

states that higher pressure does not mean "better"

for if the oil does not circulate fast enough it will

"fry" in the bearings creating abrasives, especially in

the turbo area.



It would be interesting to know if your engine is running cooler

under load with the synthetic.

 

[tgbol]

Also under so conditions one oil will run cooler than the other so vicosity can be slightly different.

 

[rbattelle]

(as indicated by the guage which I know may or may not actually provide useful information)

The gauge is not real, and (as much as you don't want to hear it) any change you've noticed on it is complete hogwash. You say it drops to the 1/4 point at idle when hot? Ha! Mine drops right to the lowest mark that indicates the start of the "safe" zone. My pressure at hot idle is 18-22 psi rock solid, 60-65 psi max highway fully warm.



You absolutely cannot believe that factory gauge, no matter how much you want to believe that it's acting differently with the new oil.

 

[CBrittan]

Yup. I agree with your comments, each of you have value to add to the discussion. Actually, I did think today that the engine was running cooler but then I am reminded that the ambient temps outside are cooler today anyway. As for the oil pressure guage, so be it. Dumb or not, makes for fun to look at it from time to time.



Would it be nice of Cuumins to give us an engine shutdown if the pressure (or oil level) dropped below whatever might be safe for our engines? I have that feature on my Detroit Series 60 12. 7 ltr.



Thanks for your comments!

 

[Cooker]

Would it be nice of Cuumins to give us an engine shutdown if the pressure (or oil level) dropped below whatever might be safe for our engines? I have that feature on my Detroit Series 60 12. 7 ltr.

This actually would not be too hard to do with a pressure switch (the trick might be finding one that will work for the application) and a relay.

 

[rbattelle]

In know that Isspro makes engine shutdown switches for pressure, temperature, water level, etc...

 

[LightmanE300]

Cbrittan - for what it's worth, when I switched to D1 my idiot oil pressure gauge showed slightly lower readings as well. I'm not worried about it at all. First oil analysis shows that the d1 is doing a fantastic job.

 

[WNowlan]

The synthetic is circulating faster, cooling the engine

at higher rate of proficiency by taking the heat away

from the bearings, especially the turbo bearings.

I've heard mechanics argue that Delo 400 does not

provide oil pressure readings as well as Rotello, therefore

they wouldn't use Delo. The American Oil Institute

states that higher pressure does not mean "better"

for if the oil does not circulate fast enough it will

"fry" in the bearings creating abrasives, especially in

the turbo area.



It would be interesting to know if your engine is running cooler

under load with the synthetic.

This is FACT.



Oil pressure is directly related to the base 5W. Both oils (15W40 and 5W40). Act like a 40 weight at operating temps. Do not pay attention to the gauge in our trucks. It basically tells us if we have pressure.



You will find a slight different in the vis of the major manufacturers of diesel engine oils on a true pressure gauge. It is not uncommon for two manufacuters of a 15W-40 oil to have different pressure curves. This does not mean one is better than the other. We blend a to a specfic range and allow for changes during a normal drain interval.

 

[gtobey]

Yup. I agree with your comments, each of you have value to add to the discussion. Actually, I did think today that the engine was running cooler but then I am reminded that the ambient temps outside are cooler today anyway. As for the oil pressure guage, so be it. Dumb or not, makes for fun to look at it from time to time.



Would it be nice of Cuumins to give us an engine shutdown if the pressure (or oil level) dropped below whatever might be safe for our engines? I have that feature on my Detroit Series 60 12. 7 ltr.



Thanks for your comments!

If you want a shutdown system, check with FWMurphy @ www.fwmurphy.com. We can help you get one if you want as we represent them as a distributor. You can look on their site and find all the distributors and choose one from there. Be careful though, as you do not want it to shutdown on you without warning. You could have that happen as you are blowing by a powerjoke or undurablemax. That could be embarrassing, let alone dangerous! Usually, our over the road panels provide a 15 second warning buzzer and light to alert you of the impending shutdown to allow you to safely pull of the shoulder of the road... If you need help, you can call me at 540-389-7296 M-F 8-5 eastern time, and I will be happy to assist! Good luck!

 

[67guzzler]

I love it when a 1 year old thread gets bumped. #ad




I'm running Rotella T 5w-40 (fake) Fully Synthetic.



I don't notice any changes in the oil pressure gauge behavior. After warmed up at idle it's just inside the left edge of the normal range.

 

[DHerzog]

I had a similar situation with my 92 Dakota... I went from 10w30 dyno oil to 10w30 synthetic and noticed a slight decrease in oil pressure on the gauge... that was 22,000 miles ago, and the truck runs fine!!!

 

[mberry]

I do not think this should be a discussion of oil used per se. This, in my humble opinion, should be a discussion about the oil filter itself. The original post says: "I also upgraded my oil filter to Fleetguard 'Stratapore'. " This leads me to believe that the oil filter itself caused a restriction which caused higher pressure readings. The guage is not that dumb (but it's not real either). It takes other measurements other than +/-6psi to read.



On my '02 I had the exact same thing happen when I was in a crunch and used a Napa filter. Oil pressure went up considerably with that filter. As soon as I could I changed it out to the Stratapore and the pressure went back down to "normal".



That's my story and I'm sticking to it!

 

[jwduke]

Oh well, its a "Blast from the past"!

 

[nickleinonen]

old thread... wow. .



i now am running 0w40 xd-3 synthetic and pressures are nearly identical to when i was running 5w40. . and i am measuring off the main gallery now too...

 

[Bertram65]

I have posted this before, it is not my imagination when I change my oil the presure on the gauge reads a little higher for a while... . still not convinced the sender is just a open or closed switch.