Should the oil pressure gauge fluctuate with engine RMPs?

[JSimoneaux]

Should the oil pressure gauge fluctuate with engine RPMs?

I just picked up my first CTD, it's a 98 12V 2500 5 speed Quad cab with 87K on the clock. The truck runs like brand new and it's 100% stock... I noticed while driving that the oil pressure will climb near 80 or higher when I'm driving but when I let it idle it'll fall to 50 or so. It never gets close to the red but I wasn't sure it that's normal or not... anyone want to give this noob some help?

 

[Devan Manis]

normal, as any engine diesel or gas. your true pressures are usually lower than what the gauge reads.

 

[JSimoneaux]

normal, as any engine diesel or gas. your true pressures are usually lower than what the gauge reads.

Thanks, I've been keeping an eye on it and it doesn't seem to change much.

 

[JMoberly]

A lot of vehicles use an idiot gauge which will point to dead center as long as there is some oil pressure. Ours shows real readings so as the engine spins faster so does the oil and pressure goes up.

 

[brods]

A lot of vehicles use an idiot gauge which will point to dead center as long as there is some oil pressure. Ours shows real readings so as the engine spins faster so does the oil and pressure goes up.

... maybe his 98 does, but your 06 ... ... ... . https://www.turbodieselregister.com/forums/showthread.php?t=141311

 

[JMoberly]

at least its a smart idiot gauge

 

[JSimoneaux]

I've also noticed that when I start the truck (warm or cold) it takes a second for the oil pressure needle to jump to 50 or 60 and it does so very quickly. Sometimes it even makes a single ding with just a split second of the check gauge light then it all goes away once the needle jumps up. There's no audible noise difference in the engine and it runs great, would this be just a bad sensor or maybe something like a dying oil pump?

 

[mberry]

Yes it will fluctuate but that pressure seems to be a little bit high and could, I repeat, could indicate a restriction in the system. As an example, I had to buy a Fram oil filter once for my '02 because I couldn't find a Fleetguard. The design of the Fram caused a restriction causing the oil pressure to rise on the guage. I am not familiar with 12V engines so this could be normal and my experience is only an example. Check your oil filter. If it's a Fleetguard, you're good. If not, I would find one that is not as restrictive, Fleetguard or one of the other high quality brands, and change it ASAP.

 

[nickleinonen]

The design of the Fram caused a restriction causing the oil pressure to rise on the guage. I am not familiar with 12V engines so this could be normal and my experience is only an example.

the only way an oil filter would show a pressure increase on the system is...

1. the gauge sending unit is pre filter on the system [more resictive filter]

2. the filter is less restrictive and you are getting more flow through the filter causing the pressure to rise in the system.

 

[Cummins Pilot]

Why are you worried about "higher" pressures? If its within engine manufactures specs more is better. Especially during high load situations.



Nick is also right, pressure is taken after the filter.