Does anyone else have a very high oil pres. when cold? Mines at 100 at idle and when you leave the driveway it's pegged at 120. Any thoughts?
Oil Psi 120?
- Thread starter LB7Diesel
- Start date
38* outside, coolant temp @ 150* and mine idles at 30..........Revs up to about 70.....I cant say as I have ever seen it get much higher than 60 - 70 though 
Mmmm. It's only this high in the mornings when everything is cold. After it reaches op temp everything looks normal. I thought it was my cluster, but i just got a new one and it does the same thing. I don't know what to think?
Lol,No, just synthetic. It's def wierd. But it's always been that way, and it comes back down to normal when hot. about 30psi idle and 60-80 when driving.
Wow! A few things come to mind.
Did you add a shim to the back of the oil pump? Prolly not if after warming up it lowers to normal, but maybe it was "below normal" and you did the mod making it "normal". I consider normal 27-30 at idle and 55-60 running down the road and 50-55 at a cold idle. But what's normal huh!
Secondly we have a secondary pressure relief in the cover, at 100 psi i would think it would have relieved or "popped off". See any spike/quick dips in the needle at those pressures?
Third what viscosity are you running? straight 50 wt maybe 30 wt? If it's a stocker i think GM suggests 5-20? Maybe you are seeing high pressure because the oil is to viscously heavy for the temp you are in, creating resistance, subsequntly giving you high pressure. The tighter the tolerances in the motor generally the lower the viscosity, stockers have tighter tolerances. ex- try and force cold peanut butter through a pinhole.
Just some thoughts.
Did you add a shim to the back of the oil pump? Prolly not if after warming up it lowers to normal, but maybe it was "below normal" and you did the mod making it "normal". I consider normal 27-30 at idle and 55-60 running down the road and 50-55 at a cold idle. But what's normal huh!
Secondly we have a secondary pressure relief in the cover, at 100 psi i would think it would have relieved or "popped off". See any spike/quick dips in the needle at those pressures?
Third what viscosity are you running? straight 50 wt maybe 30 wt? If it's a stocker i think GM suggests 5-20? Maybe you are seeing high pressure because the oil is to viscously heavy for the temp you are in, creating resistance, subsequntly giving you high pressure. The tighter the tolerances in the motor generally the lower the viscosity, stockers have tighter tolerances. ex- try and force cold peanut butter through a pinhole.
Just some thoughts.
???Wow! A few things come to mind.
Did you add a shim to the back of the oil pump? Prolly not if after warming up it lowers to normal, but maybe it was "below normal" and you did the mod making it "normal". I consider normal 27-30 at idle and 55-60 running down the road and 50-55 at a cold idle. But what's normal huh! No shims.
Secondly we have a secondary pressure relief in the cover, at 100 psi i would think it would have relieved or "popped off". See any spike/quick dips in the needle at those pressures? No spikes or dips, needle seems nice and smooth.
Third what viscosity are you running? straight 50 wt maybe 30 wt? If it's a stocker i think GM suggests 5-20? Maybe you are seeing high pressure because the oil is to viscously heavy for the temp you are in, creating resistance, subsequntly giving you high pressure. The tighter the tolerances in the motor generally the lower the viscosity, stockers have tighter tolerances. ex- try and force cold peanut butter through a pinhole.
Just some thoughts.
LB7...
I've seen many LB7's bury the needle on cold mornings, even sometimes when it's not that cold. Maybe it just got cold enough in florida for you to notice. I could go start up any one of my brother's LB7's right now (22 degrees) and everyone of them would have very high oil pressure.
LLY guys, our oiling system is a bit different that's why we don't see high pressures like this.
I've seen many LB7's bury the needle on cold mornings, even sometimes when it's not that cold. Maybe it just got cold enough in florida for you to notice.
I could go start up any one of my brother's LB7's right now (22 degrees) and everyone of them would have very high oil pressure.LLY guys, our oiling system is a bit different that's why we don't see high pressures like this.
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LB7...
I've seen many LB7's bury the needle on cold mornings, even sometimes when it's not that cold. Maybe it just got cold enough in florida for you to notice.
LLY guys, our oiling system is a bit different that's why we don't see high pressures like this.
Thanks Craig. Good to know..
..Joey
DOH! Sorry to post a response, I should have read carefully.
I didn't know you had this pressure for 3 years!
No prob, I do the same thing sometimes.. Thanks for all the suggestions guy's, was just a little concerned:hug:
Mine has done the same thing since it was new on a cold start. 120psi at idle and "holy crap" when driving for the first ten minutes or so.
Mines identacle Kevin..Good to know
I'm not sure if it's a good thing or not. But if it's still holding that kind of psi at 140K, I would think the bearings are still pretty tight. Whitch is a good thing
DP,
do you know if the pump sump dump setting was changed for the LLY?
120 is beyond what most consumer lub systems are set at, so maybe it is a calibration difference to the gauge. That's what I am inclined to think, because all LB7Diesels readings (warm and cold) run 30 psi higher than my observations.
If it wasn't a simple calibration error, you would have to change both the bypass setting, and flow rate, to get higher readings around the board. The high (120) is governed at the pump itself. The warm pressure is governed by viscosity (temp and oil grade) and pump capacity flow rate.
Anyway, that's my rationalle for concluding that there is nothing abnormal. IOW, what has already been stated by others. Use 5W-XX oil. 15W- is not a good winter choice up North IMO, but not wrong in Melbourne. I use 5W in PHX.
do you know if the pump sump dump setting was changed for the LLY?
120 is beyond what most consumer lub systems are set at, so maybe it is a calibration difference to the gauge. That's what I am inclined to think, because all LB7Diesels readings (warm and cold) run 30 psi higher than my observations.
If it wasn't a simple calibration error, you would have to change both the bypass setting, and flow rate, to get higher readings around the board. The high (120) is governed at the pump itself. The warm pressure is governed by viscosity (temp and oil grade) and pump capacity flow rate.
Anyway, that's my rationalle for concluding that there is nothing abnormal. IOW, what has already been stated by others. Use 5W-XX oil. 15W- is not a good winter choice up North IMO, but not wrong in Melbourne. I use 5W in PHX.
I'm not really sure what the actual differences are.
Comparing my LLY to any one of my families LB7's (6 total), my oil pressure is considerable lower at all stages of driving, outside temp, engine temp, etc.
Pat has likely seen both oiling systems, he would probably know what the differences are.
Comparing my LLY to any one of my families LB7's (6 total), my oil pressure is considerable lower at all stages of driving, outside temp, engine temp, etc.
Pat has likely seen both oiling systems, he would probably know what the differences are.
mine did it this morning joey, probably does it every morning but i actually looked at it this morning, idled a little over 100psi but when it started to get warm it went back to 30psi idle
Nothing wrong.
Just an LB7 thing.
I put a Autometer 100 psi gage on mine and had no problem pegging it on cold winter mornings. I run dino Pennzoil.
Just an LB7 thing.
I put a Autometer 100 psi gage on mine and had no problem pegging it on cold winter mornings. I run dino Pennzoil.