Low oil pressure on new motor?
07-18-2006, 01:55 AM
#1
Low oil pressure on new motor?
On the 6.0 my oil pressure seems a little low to me. The motor has a LS6 ported oil pump, LS6 valley cover, I have also drilled holes in the lifter cups in order to release oil build up in the top. The motor is running 11.1 compression with a comp 230/236/.591/.601 110lsa. I just had to replace the oil sending unit because it was reading past 80 even with the key on and the motor not running. The oil pressure is sitting at the first bold mark at idle 20psi and 40 psi. and will increase as the throttle increases. It seems to go straight to 40 if you give it any type of gas and is at 45 or so at 35-40mph. The truck idles at about 900 rpms. Is this a problem? I may be wrong but I think the 4.8 was running around 40-50 psi at idle with the ported pump. My new motor has about 500 miles on it and I have just changed the oil. I am using 10w-30 castrol gtx, and plan on going to roayal purple on the next oil change. Just wondering if I have a need for concern? If so what maybe the problem. I had rebuilt the motor before putting it in and it seems to run really well I just thing the oild pressure seems low.
Last edited by Dark Halo; 07-18-2006 at 02:21 AM.
07-18-2006, 10:24 AM
#2
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Seems too low to me. My 05' LQ9 with about 2K miles has about 40psi at idle and about 70psi at WOT.
Thats with my stock 5.3 oil pump.
I thought I read that ported pumps show lower psi but flow more volume.
Even then I would think you have more than 20psi at idle.
Positive that you didn't mess up the O-ring?
Thats with my stock 5.3 oil pump.
I thought I read that ported pumps show lower psi but flow more volume.
Even then I would think you have more than 20psi at idle.Positive that you didn't mess up the O-ring?
07-18-2006, 10:29 AM
#3
Rule of thumb is 10psi for every 1000 rpm. I think the lower pressure will be from the ported oil pump. I would keep an eye on it and see if it gets any worse. What oil are you running? If you are still breaking it in on dino oil I would run a 10w-40 or 0w-40 synthetic when you switch to synthetic. As long as it doesnt get worse and pressure climbs good with rpm's I would think it's fine.
07-18-2006, 11:59 AM
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Originally Posted by ranwalk
Rule of thumb is 10psi for every 1000 rpm. I think the lower pressure will be from the ported oil pump. I would keep an eye on it and see if it gets any worse. What oil are you running? If you are still breaking it in on dino oil I would run a 10w-40 or 0w-40 synthetic when you switch to synthetic. As long as it doesnt get worse and pressure climbs good with rpm's I would think it's fine.
07-18-2006, 01:36 PM
#6
I am running a stock pump in my LQ9 and am seeing lower pressure than in my 5.3. The 5.3 would idle above 40, then go up to 70 or so when cruising at 2300 RPM. My LQ9 idles around 30 psi once it gets hot, cruises around 45-50 at 2000-3000 RPM, then will shoot way up when I am WOT. I have been following the 10 psi per 1000 RPM rule, so I'm not worried about it yet but I feel like I am having to keep my eye on it all the time 
07-18-2006, 01:45 PM
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Do you have scanning capability? I would think with your mod level it should be on your tool list. You can monitor the oil pressure the PCM sees before it hits your gauge. That would be a more true-r reading than your dash gauge. It could be off. None of mine, except speedo, are right on.