6.4L Oil Pressure - Idle vs Cruising

[heefageLA]

Im learning more everyday about my new 6.4L. I notice while cruising the oil pressure is a nice 50-52 psi. While stopped today, dropping kids off at school, I noticed my oil psi dropped to 29 psi.
Is this normal? Im waiting on a larger oil filter to arrive that will help boost it a bit at idle, but 29 psi seems LOW for a big ol' 6.4L V8.

Just looking for you guys thoughts that have experience with this engine.
Thanks

 

[quickster2]

Normal readings for me FYI. Curious as to how a larger oil filter will boost idle pressures?

 

[heefageLA]

Normal readings for me FYI. Curious as to how a larger oil filter will boost idle pressures?

That was my experience with using a larger oil filter on my 1500. I always thought of it like a water hose, finger over the hole = more pressure / less volume, finger off the hole = less pressure / more volume
To my surprise, a larger oil filter raised my idle psi a few points... Im sure there are folks here who can explain why that occurs, im a bit lower on that totem pole.

 

[Dean2]

Your pressures match mine. I would actually like to bump the idle RPM about 100 to 150 revs, which would keep the oil pressure closer to 40 psi, but have not found an economical way to do that. Good thing is, pickup doesn't idle all that much so not a real big deal. So far only used factory filters so can't help on that front.

 

[heefageLA]

Normal readings for me FYI. Curious as to how a larger oil filter will boost idle pressures?

See below for a dirty answer on why you increase psi with a larger filter.

"With the dual filters i picked up a couple psi from idle on up to redline,as there's less pressure drop across 2 filters then 1 filter"

Remote Oil Filtration System

Has anyone done a remote oil filter for the 6.4? I have a 2018 Ram 2500 with the 6.4 Hemi. The oil filter for this engine is ridiculously small. After 5000 miles the oil looks like diesel oil. Wondering if there is a remote filtration system out there that uses a larger filter.

www.ramforum.com

 

[heefageLA]

Your pressures match mine. I would actually like to bump the idle RPM about 100 to 150 revs, which would keep the oil pressure closer to 40 psi, but have not found an economical way to do that. Good thing is, pickup doesn't idle all that much so not a real big deal. So far only used factory filters so can't help on that front.

Im pretty adamant about not idling my truck either. I actually passed up buying a '22 2500 because it had a crazy high idle hours number.

 

[rzr6-4]

While I can't say I know what your pressures are supposed to be, my dad's 1952 chevy idles around 5psi so I wouldn't worry about 29psi. (Totally different vehicle but physics doesn't change.)

 

[HemiLonestar]

Im learning more everyday about my new 6.4L. I notice while cruising the oil pressure is a nice 50-52 psi. While stopped today, dropping kids off at school, I noticed my oil psi dropped to 29 psi.
Is this normal? Im waiting on a larger oil filter to arrive that will help boost it a bit at idle, but 29 psi seems LOW for a big ol' 6.4L V8.

Just looking for you guys thoughts that have experience with this engine.
Thanks

No it isn't, and you can't compare idle stopped to cruising pressures; idle is always gonna be significantly lower. SRT 6.4 hot idle oil pressure is right around 35 psi, little less if I've been flogging it (and they use the same oil pump). It's fine. If it starts to drop closer to 20 psi then it might be cause for concern but technically you would still be within what OEM considers "acceptable".

 

[DILLIGAF]

Easy fix, just bump the idle up to 750rpm

 

[Dean2]

Easy fix, just bump the idle up to 750rpm

Without doing a tune, still under warranty, how did you do that?

 

[heefageLA]

Easy fix, just bump the idle up to 750rpm

I got about 40,000 miles and a few years to go before thats an option.

 

[HEMIMANN]

6.4L Hemi owner here.

With engine @ operating temp, idle = 35 psi, running = 55 psi. +/- 2 psi depending on outside temp (we get wide temp swings here).

Oil = Red Line 5W-30 (summer), 0W-30 (winter)
Filter(s) = Royal Purple 20-500, Fram XG10060

 

[heefageLA]

6.4L Hemi owner here.

With engine @ operating temp, idle = 35 psi, running = 55 psi. +/- 2 psi depending on outside temp (we get wide temp swings here).

Oil = Red Line 5W-30 (summer), 0W-30 (winter)
Filter(s) = Royal Purple 20-500, Fram XG10060

Perfect response! Im currently using Mobil 1 0w-40 w/ Lubegard and Wix OEM sized filter.
Next OCI, Ill use the RP 20-500 and Redline oil. Dont know which visc. ill use yet.

It appears the RP 20-500 size filter will boost the pressure a few psi, based on your comment.

 

[clayinfla]

My psi is pretty similar. Typically 52 running. 28 idling warm.

 

[Jeff Courtney]

I just had to replace the 6.4 in my '18 3500 at only 105,000 miles due to "catastrophic failure". Used the recommended Penzoil w/Mopar filters @ reg serv sched. New engine oil pressure is similar to yours. Gets up to 50+ with any RPM above idle.
Truck had 1900 hours at idle. 3100 driving, 5000 total at engine replacement. Had to replace the 66RFE at same time. That was an expensive mont! $25K

 

[HemiLonestar]

 

[1STRAM2500]

I just had to replace the 6.4 in my '18 3500 at only 105,000 miles due to "catastrophic failure". Used the recommended Penzoil w/Mopar filters @ reg serv sched. New engine oil pressure is similar to yours. Gets up to 50+ with any RPM above idle.
Truck had 1900 hours at idle. 3100 driving, 5000 total at engine replacement. Had to replace the 66RFE at same time. That was an expensive mont! $25K

Wow! That's a lot of idle time. I was worried my idle time was too high at about 7-8%

 

[Aggie12]

Pretty much exactly the numbers I have with my 2024. No worries, the numbers are fine. On the other note, oil filters don't control the oil pressure.

 

[Wild one]

Pretty much exactly the numbers I have with my 2024. No worries, the numbers are fine. On the other note, oil filters don't control the oil pressure.

The filter can definitely affect the oil pressure on a hemi.Oil pressure is measured after the filter on a Hemi,so a poor quality filter can and will affect the pressure.

 

[DILLIGAF]

I guess at 50 PSI Idle my filter is fine