Oil pressure dropping

[carco]

(07-19-2020 )Mattman Wrote:  What's oil pressure when cold start up?

"Cold start" up in a 90 degree shop in AM is not exactly cold,,, Will be maxed about 39psi per dash gauge.

[carco]

(07-19-2020 )tree98 Wrote:  What's you oil temp been?

Oil temps run 200-220 consistently.

[carco]

(07-19-2020 )Rawze Wrote:  

(07-19-2020 )carco Wrote:  Hello to all during this hot stretch,
2009, T8, ISX550, 326000 miles, 14400 hours, empty weight 52K, loaded usually 65K to 90K often up to 130K but has been up to 167K, and once 232K.
Oil pressure has been dropping last 4-4500 miles 68mph, 1700rpm oil 39psi is now 33psi hot.
Hot idle oil psi now 16psi was always over 20psi. No power difference, no sound difference.
Was ready for oil change, 10 to 12K service intervals, so changed oil, made no difference. Changed oil sending unit, no difference.
So am I in trouble just over the next hill?? just keep an eye on the oil press?? tear down the engine, pull rocker cover chk cam, pull pan chk rods and mains??
Any words of wisdom?
Thank you.

just an FYI: If you had claimed that oil pressure comes bnack whenever the filter is changed, that is a common issue.. but you did not state this. - In the case of oil pressure falling off, then a fresh oil change and filter makes it come back, that is a sign of severe soot packing in the oil.

-- If your oil pressure has fallen off that much, and it is consistently bad ... I would pull the enigne cover and check for a spun bearing on the cams first. --Then the bottom end to ensure something is not getting beat to death, and check for debrtis in the pan. -- still nothing.... then replace rod and main bearings and replace oil pump while your at

When replacing rod/main bearings: -- BE SURE TO MEASURE all your rod and main bearings, as some ISX engines have alternate sizes and this can really screw things up. Not all ISX's come with standard size bearings from factory. They can also sometimes be different from hole to hole too.

Rawze,,
None to very minor oil pressure change when oil is changed.

Oil pressure has dropped to about 38-44psi hot. At cruise 1700 rpm/68mph steady flat terrain will vary at times down to 38psi and back to 34psi. Also hot low idle about 14-15 psi now.

New oil sending unit was No different than the old unit.

Was really hopeing someone would say YES, this very thing occurred and this is what worked,,,,,,. Theharjot is the closest to answering this way!! Thinking about starting that direction w/new oil pump and pulling cover to look at top of head for problems. After a manual gauge chk.
Thanks to all for your time and thoughts!!

On another note I need to see why I have not received email notices on your posts!! That is why I have been so long to respond back, busy and did not know of the responses! Thanks again

[JimT]

(07-29-2020 )carco Wrote:  On another note I need to see why I have not received email notices on your posts!! That is why I have been so long to respond back, busy and did not know of the responses! Thanks again

I believe Rawze has them disabled. Easiest way I found to keep up with replies and new posts is to use the "Latest Posts" button up top.

[Rawze]

(07-29-2020 )carco Wrote:  ... about 38-44psi hot. At cruise 1700 rpm/68mph steady flat terrain will vary at times down to 38psi and back to 34psi.


Also hot low idle about 14-15 psi now.
...

34 psi is only a psi or so lower than normal. 35,36+psi when going down the road and engine is hot is ok oil pressure for an isx, and is quite normal. 34 would be normal if the oil temps are getting high though (above 230+).

14-15 is a bit low for idle pressure though. -- it should be around 18, maybe 20-22 or so usually.

sounds like some internal hemorrhaging of oil somewhere (like mentioned above,... spun cam bearing, loose or improperly installed retainer bolt on a rocker shaft,... excess wear on rocker bearings, excess wear on a rod or main bearing ... ... something ... , or possibly something wrong with the pump.

what are oil temps running?

maybe pull valve cover, crank it up, watch for excessive oil gushing out somewhere?

[carco]

what are oil temps running? -------- about 200-220'

Sorry about incorrect pressure figures above. Hot @ 1700rpm is 28-44psi,, 4000 miles ago was 38-39psi.
Hot low idle was always over 20-22 psi 4000 miles ago------ now is 14-16psi.

[Nostalgic]

(07-29-2020 )carco Wrote:  Was really hopeing someone would say YES, this very thing occurred and this is what worked,,,,,,. Theharjot is the closest to answering this way!! Thinking about starting that direction w/new oil pump and pulling cover to look at top of head for problems. After a manual gauge chk.
Thanks to all for your time and thoughts!!

I'd pull the valve cover and check running to see if any can bearings are spun or flowing too much oil - it's the easiest.

I had low hot oil presssure and my adjustable idler gear bearing ended up being the main culprit. Harder to check without getting into things, but you can get a finger on it by taking the oil fill tube off to see if you feel any play (other than normal backlash).

[carco]

OK. Pulled pan chked a rod and a main near engine front. Looked ok bit of dirt evidence. installed updated oil pump, no pressure change. Ran a couple days and pulled pan again and pulled girdle/windage tray chked rod and main near rear of engine decent. Left pan off overnight. Next AM found puddle of coolant under #3, a drop on liner bottom. Pulled head cam bearings showed copper. #3 liner cracked about 1.5 inches so inframed, w/reman head, pressure relief in filter head, dampener, new updated oil pump, first time reman injectors, counterbored block, Cummins parts. Engine much quieter and smoother one 40 mile trip at over 105K steep hills and turns, almost 800 miles on inframe.

Still shows max oil pressure of 34-35 hot and 35 max cold high idle no load at 1700rpm and 20-22 psi at hot idle.

Question???
Is there a good place to add a manual gauge permanently. Maybe access small filter head port?? or oil cooler port?? or a better access port???

Thank you!

[Rawze]

(09-06-2020 )carco Wrote:  ...
Question???
Is there a good place to add a manual gauge permanently. Maybe access small filter head port?? or oil cooler port?? or a better access port???

Thank you!

put a "t" where the oil pressure sensor is?.