R.E.D Posted December 24, 2017 Share Posted December 24, 2017 So its been almost a year since I installed the mech e7-350 in the rd.Everything runs as it should , but I cant get over the fact that at 180 degrees of coolant temp the oil pressure is at 15 psi at idle.Its a very low mile engine and it worries me that the oil pressure seems so low.Can deformed oil spray nozzles that cool piston cause oil pressure to drop?Or maybe worn out pump?It does peg the needle to 75psi at WOT. Quote Link to comment https://www.bigmacktrucks.com/topic/52031-low-oil-pressure/ Share on other sites More sharing options...
terry Posted December 24, 2017 Share Posted December 24, 2017 Might be a little on low side, but I have seen these engines run this way for years and years. Nothing to get concerned about. terry Quote Link to comment https://www.bigmacktrucks.com/topic/52031-low-oil-pressure/#findComment-388098 Share on other sites More sharing options...
58GreenMackB Posted December 24, 2017 Share Posted December 24, 2017 I've been going through something similar on my B61. Engine fires right up even in cold weather so I know the injection pump is good and that I have good compression. However, if I run it in summer I will get 6-8 PSi at idle, but 32psi running down the road. I talked to my machinist about what could be wrong and how to correct it. He agrees the pressure is way too low, but knowing where the "leak" is requires tearing into the motor. It could be too much clearance in the main or connecting rod bearings, could be a failing oil pump, pressure relief valve that is stuck closed, faulty oil pump relief valve, a restriction in the oiling system, faulty oil pressure pick up etc. I'm sure someone else could give you some more information on things to test. In my research though, some of these engines run for years this way and never miss a beat. I'll find out the cause next spring when we tear into it, but I understand the concern. Quote Link to comment https://www.bigmacktrucks.com/topic/52031-low-oil-pressure/#findComment-388114 Share on other sites More sharing options...
R.E.D Posted December 24, 2017 Author Share Posted December 24, 2017 according to my e7 manual im within spec, but its just grinds my gears as to why is so low.both my 98 etech and 96 427 are above 25psi when hot.therefore i thought of the piston spray nozzles.i deduced that if pump was bad it would not go up 75 when hot. Quote Link to comment https://www.bigmacktrucks.com/topic/52031-low-oil-pressure/#findComment-388117 Share on other sites More sharing options...
58GreenMackB Posted December 24, 2017 Share Posted December 24, 2017 The old rule of thumb I've heard is a minimum of 10 psi for every 1000 rpm. Of course, this is just a rule of thumb and it really depends on the motor you're dealing with and that everything is getting sufficient lubrication. There so many factors that affect oil pressure, which explains why manufacturers list such a wide variance as within spec. I wouldn't worry about it unless it starts to drop closer to the 10 psi number. Quote Link to comment https://www.bigmacktrucks.com/topic/52031-low-oil-pressure/#findComment-388140 Share on other sites More sharing options...
Fastforword Posted December 25, 2017 Share Posted December 25, 2017 Had an r 600 do that I was a relief valve on the filter housing that was stuck open. They rarely get serviced. Quote Link to comment https://www.bigmacktrucks.com/topic/52031-low-oil-pressure/#findComment-388201 Share on other sites More sharing options...
R.E.D Posted December 25, 2017 Author Share Posted December 25, 2017 Do e7 have this this relief valve as well? Quote Link to comment https://www.bigmacktrucks.com/topic/52031-low-oil-pressure/#findComment-388211 Share on other sites More sharing options...
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