Dod oil pressure relief
08-25-2009, 09:03 AM
#1
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Dod oil pressure relief Can you plug the DOD oil pressure relief in the pan? I'm not running DOD and lifters are gone. I'm not for sure what needs to be done to the pressure relief. It looks like it regulates oil pressure to 55-75psi.
08-26-2009, 06:37 AM
#3
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It has been done successfully with a resultant increase in oil pressure. Sometimes too much sometimes only a little. Depends on the particular engine and which oil pump it has.
08-26-2009, 08:48 PM
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I'm running a Melling 10296 with stock blue spring. I'm wondering how I'm going to plug it. It has a 14mmx1.5mm threaded relief in the pan. I haven't found anything to plug it with those threads.
08-26-2009, 10:43 PM
#5
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Why would you want to mess with plugging it? It is only a high pressure relief, and if you do not have high pressure, it will never relieve. If you do have high pressure, why would you not want it to be relieved?
Regards, John McGraw
Regards, John McGraw
08-27-2009, 06:30 AM
#6
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The primary purpose of the pressure relief valve in the oil pan is with DOD/AFM engines with higher volume oil pumps to support the DOD/AFM oil usage and probably also with VVT.
With 30% higher flow in these cold start oil pressure (sub zero locations) can be through the roof and exceed the specs of the DOD/AFM solenoid valves which it appears maxes out just north of 75psi.
In non DOD/AFM engines, they may bleed some pressure off even with the stock oil pump if the engine is tight oil wise.
If you have 50psi hot and want to chase the "rule of thumb" 65psi at 6500rpm (which is way above GM specs, but then GM specs arent for racing
), then maybe you will get there by blocking the relief off. You may also get 100psi and be driving the oil pump real hard and taking more power that is unnecessary, and possibly heat the oil up further than normal. And if the DOD/AFM solenoids are still there, well, maybe they will give up.
GM put the relief in there for a reason. If you have 55-65psi hot (like 210-220 hot), then you probably dont need to worry about any more pressure.
With 30% higher flow in these cold start oil pressure (sub zero locations) can be through the roof and exceed the specs of the DOD/AFM solenoid valves which it appears maxes out just north of 75psi.
In non DOD/AFM engines, they may bleed some pressure off even with the stock oil pump if the engine is tight oil wise.
If you have 50psi hot and want to chase the "rule of thumb" 65psi at 6500rpm (which is way above GM specs, but then GM specs arent for racing
), then maybe you will get there by blocking the relief off. You may also get 100psi and be driving the oil pump real hard and taking more power that is unnecessary, and possibly heat the oil up further than normal. And if the DOD/AFM solenoids are still there, well, maybe they will give up.GM put the relief in there for a reason. If you have 55-65psi hot (like 210-220 hot), then you probably dont need to worry about any more pressure.
08-27-2009, 07:43 AM
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They don't have the relief on older pans. I have a LS2 engine with a truck oil pan on it that was DOD. The pump is a melling 10296. The factory pump was high volume. The VLOM or solenoids are gone with the lifters too so I don't see why you would need it in there. The relief can open anywhere from 55psi-75psi according to the specs. I really don't see why it would matter since other engines weren't fitted with this. Just vehicles that were retro-fitted with DOD or Active Fuel Management.
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08-27-2009, 07:46 AM
#8
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They don't have the relief on older pans. I have a LS2 engine with a truck oil pan on it that was DOD. The pump is a melling 10296. The factory pump was high volume. The VLOM or solenoids are gone with the lifters too so I don't see why you would need it in there. The relief can open anywhere from 55psi-75psi according to the specs. I really don't see why it would matter since other engines weren't fitted with this. Just vehicles that were retro-fitted with DOD or Active Fuel Management.
08-27-2009, 07:55 AM
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I ran this with a different engine without dod and LS7/cam. The oil pump was also aftermarket and oil pressure would go to about 55psi and that was all. I'm thinking it was relieving pressure then. I'm going to plug it with a 14mm drain plug and gasket with red loctite on it.
08-27-2009, 11:43 PM
#11
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My point is, do you need more than 55 PSI of oil pressure? If not, then why mess with trying to plug something that causes no problem? None of my engines ever go over 55 PSI and my LS1 seldom makes over 40 PSI.
Regards, John McGraw
Regards, John McGraw
02-12-2019, 03:50 PM
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OK hopefully this is not too far off topic. The truck I am working on is a 2007 with a 4.8l. I initially tore into it because it had a really bad lifter tick. I checked the oil pressure using the port on the back of the valley where the sensor is mounted (40 PSI). Replaced all of the lifters and put it back together and started it. Ran smoothly for a short time until the light (there is no gauge) turned on indicating low oil pressure. The lifter still sounded quiet and the truck was running smoothly. I initially suspected the sensor was faulty so I opened the port to the driver side of the oil pump on the block to confirm the pressure. Right off it looked good and then dropped to 20PSI which is as high as it has gotten since. I next suspected the O-ring on the pickup tube, Changed that and still no change. Out of time and patience, I turned it over to a Mechanic friend to replace the oil pump thinking it was the pressure relief valve in the oil pump. After replacing it, he is indicating that its pressure is still low. So far there is no indication of Metal in the pan so I am doubting bearing wear. I am at a loss. the only thing I can think of is, is this DOD oil pressure relieve valve has failed From the research I have done it, seems like it is something to do with if you have the Cylinder shutoff and this truck does not have that feature. it is possible that, that part is what has failed?
02-12-2019, 03:56 PM
#13
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4.8 engines don't have DOD.
02-12-2019, 04:45 PM
#14
Depends which oil pump vs accessories you run. The DoD/VVT engines are equipped with enough oil pump volume to control both under all called upon conditions, simultaneously. When these are not in use, surplus oil can vent out the relief valves. This relief valve also insures DoD control pressure does not exceed 55psi or so.
My stock 5.3L Colorado does not have this oil pan mounted relief valve. It also does not have the higher volume oil pump.
I would match the necessity of the oil pan mounted relief valve to the oil pump you are using.
My stock 5.3L Colorado does not have this oil pan mounted relief valve. It also does not have the higher volume oil pump.
I would match the necessity of the oil pan mounted relief valve to the oil pump you are using.
02-12-2019, 06:21 PM
#15
what about CTS-V pans? I used one for my swap and don’t remember if it had one or not. Read a few things about people plugging them up since the filters also have a pressure relieve built into them too
02-13-2019, 12:04 PM
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I'm removing and plugging the valve in my G8. No need for it with a DOD delete. But I'm also removing the factory high volume oil pump and going with a standard LS3 pump.
No need for a high volume without DOD.
The pumps already have reliefs so no need for a second.
My theory on why its there may be due to the DOD valves abruptly opening and closing, it relieves the pressure spikes.
No need for a high volume without DOD.
The pumps already have reliefs so no need for a second.
My theory on why its there may be due to the DOD valves abruptly opening and closing, it relieves the pressure spikes.
02-13-2019, 12:06 PM
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The filter housings don't have reliefs they have a bypass.
Last edited by L78steve; 02-13-2019 at 01:44 PM.
02-13-2019, 05:23 PM
#18
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I'm removing and plugging the valve in my G8. No need for it with a DOD delete. But I'm also removing the factory high volume oil pump and going with a standard LS3 pump.
No need for a high volume without DOD.
The pumps already have reliefs so no need for a second.
My theory on why its there may be due to the DOD valves abruptly opening and closing, it relieves the pressure spikes.
No need for a high volume without DOD.
The pumps already have reliefs so no need for a second.
My theory on why its there may be due to the DOD valves abruptly opening and closing, it relieves the pressure spikes.
02-13-2019, 05:38 PM
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https://static.nhtsa.gov/odi/tsbs/20...62524-7690.pdf
03-25-2019, 09:04 PM
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OK, so I was looking at this now that the oil pump was replaced and still no real pressure to speak of. I removed the pan and the DOD from it. the spring inside is really easy to depress (approx. 5 lbs) considering it is supposed to hold back 55 LBS/in^2 (PSI) that does not seem right at all. I think I just need to plug it. unfortunately, it may be too late since this time it looks like thick grainy mud in the pan. Anyone know the thread size of the plug I need?