• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Hope I dont have a problem?????

T

toytruckman

New Member
Messages
71
Reaction score
0
Location
Metairie LA
So I change my oil (was Rotella 15-40w dino) every 5000mi truck just turned 35K so I think switch to synthetic kool right? New oil: Rotella T-6 5-40w. So now do I have a problem? Oil pressure was above first "big" line on gauge at hot idle, now pressure is below the line :confused:
If I go by my dash gauge it looks like about a 10 to 15psi drop in pressure :sad:
You all think this is ok????? I was not expecting a "drop" in pressure????

Also I did switch oil filter brands; from AC Delco to Fram. I know lots of you dont like Fram but I'm now wondering if the new filter does not have as much restriction, that would account for lower pressure?
What does evry-one think???

Thanks Dave
 
I think lower oil pressure with synthetic is normal, using a Fram is not...):h

Syn oil can be a reason for a lower pressure, 15 psi is on the steep end of this though. Not a fan of Fram filters, maybe they are better now, but I'm stickin' with the AC Delcos.
 
Fram stinks and you can expect a 10 psi pressure drop, I run amsoil and at 65 mph I am running 55 psi.btw...why did you change weights...I would still run 15W40.....not 5-40w thats another reason your pressure dropped.
 
I had the same question before. I asked Ashton(TheOilGeek) and he told me that you should have apx. 10psi for every 10mph you are running. Obviously if your running 70mph and see 35psi that is okay. Once my oil has warmed up I always see just over 30psi. Another thing he said was that running synthetic makes for less friction in the engine which in turn cause less oil pressure. I am sure he chime in this thread and explain a little better then I did.
 
RYDNHI4X4 said:
I had the same question before. I asked Ashton(TheOilGeek) and he told me that you should have apx. 10psi for every 10mph you are running. Obviously if your running 70mph and see 35psi that is okay. Once my oil has warmed up I always see just over 30psi. Another thing he said was that running synthetic makes for less friction in the engine which in turn cause less oil pressure. I am sure he chime in this thread and explain a little better then I did.
Click to expand...

For a gasoline racing engine the old rule of thumb was 10 psig per 1000 rpm, eg 30 psig for 3000 rpm up to about 70-80 psig, above that you had danger of spinning a cam bearing due to too much oil pressure. (Old school stuff)

What you are observing is the reduction in head loss.

Head loss is a measure of the reduction in the total head (sum of elevation head, velocity head and pressure head) of the fluid as it moves through a fluid system. Head loss is unavoidable in real fluids. It is present because of: the friction between the fluid and the walls of the pipe; the friction between adjacent fluid particles as they move relative to one another; and the turbulence caused whenever the flow is redirected or affected in any way by such components as piping entrances and exits, pumps, valves, flow reducers, and fittings. (http://www.engineersedge.com/fluid_flow/head_loss.htm)

This perfectly normal. The oil does not 'stick' to itself or the engine components nearly as much as your old dino oil did.

This reduction in drag on the oil pump, and to a lesser extent all of the other oil bathed engine components, is the mechanism by which you end up with more energy output from the engine reaching the wheels, instead of being a parasitic loss in the engine (a net gain in efficiency). Hence the small mileage gains seen with synthetic lubricants.

Hope this helps.

Fram:mad2:
 
It is normal pressure for the lighter weight 5W-40 oil. Our 2006 Duramax's have a higher volume lower pressure oil pump. They say although the pressures may not be as high, they pump more oil over the internals. Refer to it as using a squirt gun to rinse your car, or a garden hose. ;) No worries.

Now with the FRAM! Oh boy. I personally stay away. I cut open many filters. The FRAM filters have crappy dedia inside them and are cheaply built in my opinion. There is nothing wrong with the stock AC Delco's or several others, but just say NO to the Frams.
 
Rotella T 15w-40 has a kinematic viscosity of 15.7 cSt at 100C vice 14.2 cSt for the 5w-40 Rotella T6 synthetic. That is a little lower but both fall squarely into the 40 weight range at operating temperature.

The main cause of the drop in indicated oil pressure is due to a reduction in the resistance to flow as discussed above.

For comparisons sake the Rotella T 10w-30 has a kv of 11.9 cSt at 100C.
 
Thanks for correcting that Ashton, I had it wrong.


Wrecker said:
For a gasoline racing engine the old rule of thumb was 10 psig per 1000 rpm, eg 30 psig for 3000 rpm up to about 70-80 psig, above that you had danger of spinning a cam bearing due to too much oil pressure. (Old school stuff)

What you are observing is the reduction in head loss.

Head loss is a measure of the reduction in the total head (sum of elevation head, velocity head and pressure head) of the fluid as it moves through a fluid system. Head loss is unavoidable in real fluids. It is present because of: the friction between the fluid and the walls of the pipe; the friction between adjacent fluid particles as they move relative to one another; and the turbulence caused whenever the flow is redirected or affected in any way by such components as piping entrances and exits, pumps, valves, flow reducers, and fittings. (http://www.engineersedge.com/fluid_flow/head_loss.htm)

This perfectly normal. The oil does not 'stick' to itself or the engine components nearly as much as your old dino oil did.

This reduction in drag on the oil pump, and to a lesser extent all of the other oil bathed engine components, is the mechanism by which you end up with more energy output from the engine reaching the wheels, instead of being a parasitic loss in the engine (a net gain in efficiency). Hence the small mileage gains seen with synthetic lubricants.

Hope this helps.

Fram:mad2:
Click to expand...
 
Thanks to all :D

Ok I get it with the other than AC Delco filter; I will get one from dealer monday and swap out the (non-recommend) filter:thumbsup:

Again a big thanks a bunch to all; sure had me scared :eek: though at first.


Thanks Dave
 
toytruckman said:
Thanks to all :D

Ok I get it with the other than AC Delco filter; I will get one from dealer monday and swap out the (non-recommend) filter:thumbsup:

Again a big thanks a bunch to all; sure had me scared :eek: though at first.


Thanks Dave
Click to expand...

To be clear, there are many quality filters on the market. Purolator, Bosch, Mobil 1, K&N, Wix, Motorcraft (dare I say?), just to name a few. And Amsoil/Donaldson at the top of the list for the Nanofiber offering.
 
toytruckman said:
Ok I get it with the other than AC Delco filter; I will get one from dealer monday and swap out the (non-recommend) filter:thumbsup:
Click to expand...


Dave, if you chose do go with the AC Delco I would try Auto Zone or another local store. Before I switched to the Amsoil filter I got them all from Auto Zone. They also carry a few that Ashton mentioned as well. The dealer will more than likely be more expensive.
 
When I first purchased my truck a fuel fitler from the dealer cost me $60. Definitely go to Autozone, etc.
 
You must log in or register to reply here.
Back
Top