Oil pan sucking Dry?
I suppose it's possible depending on what pressure is going up to on the relief and anything that goes over the relief channel gets funneled back into the suction stage of the pump which will cut down on what the pickup pulls in. Did you set the pick height to the bottom of the oil pan?
THIMK: the ONLY oil that makes it out of the pan and up into the rest of the motor, is that which passes through the bearing clearances, lifters, etc. This is TOTALLY dependent on the clearances themselves, and the oil pressure. All of the oil that the pump gears move butt that DOESN'T pass through those places, goes right back to the pickup side of the pump; IOW, the oil that the gears move that's in excess of what the clearances allow to flow, makes a circuit running around INSIDE the pump. It therefore DOES NOT MATTER what the pump's volume capacity is; the ONLY oil that gets past it, is what the clearances allow.
Your problem is the oil running to the back of the pan and uncovering the pickup. You can demonstrate this to yourself by simply adding a bit extra to the crankcase; maybe ½ quart or so, not enough to rise above the level of the tray in the pan, butt enough to help keep the pickup submerged. If this cures, or at least significantly lessens, your problem, then you have your explanation. Either run the slightly higher oil level all the time, or get a pan with better baffling.
THIMK: the ONLY oil that makes it out of the pan and up into the rest of the motor, is that which passes through the bearing clearances, lifters, etc. This is TOTALLY dependent on the clearances themselves, and the oil pressure. All of the oil that the pump gears move butt that DOESN'T pass through those places, goes right back to the pickup side of the pump; IOW, the oil that the gears move that's in excess of what the clearances allow to flow, makes a circuit running around INSIDE the pump. It therefore DOES NOT MATTER what the pump's volume capacity is; the ONLY oil that gets past it, is what the clearances allow.
Your problem is the oil running to the back of the pan and uncovering the pickup. You can demonstrate this to yourself by simply adding a bit extra to the crankcase; maybe ½ quart or so, not enough to rise above the level of the tray in the pan, butt enough to help keep the pickup submerged. If this cures, or at least significantly lessens, your problem, then you have your explanation. Either run the slightly higher oil level all the time, or get a pan with better baffling.
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Those are the KEY words. Has NOTHING WHATSOEVER TO DO with "volume". Only PRESSURE. (and of course clearances)
He did prove that oil hitting your crank turns into foam and foam doesn't pump.
Additionally, you need 3/8" between the pan and pickup
The oil pump has no more oil to pick up which is causing your pressure drop, AKA it's dry in the pan where the pickup tube is. The oil is in every other location, except where it needs to be and running high volume high pressure pumps can make this worse. It happens in f-body oil pans a lot due to the pickup location and terrible baffling, BUT it happens in plenty of others as well as dry sump systems with high pressures. I've literally watched a dry sump setup on a GenIV LS and GenV LT put enough oil up into the tops of the heads and block to starve itself at the end of a 1/4 mile rip, a wet sump LS would have starved itself in a 1/10th of the time at the 60ft. Running less pressure and running restricted pushrods was the only thing to keep it from having the issue at 8000 rpms.
Now this is where you guys can complain about the pickup technically still having an oil film on it so it's not really "dry".
To me, a native speaker of English, it would mean, pumping all the oil out of the pan ("suck"), and putting it someplace else, such that there's none left in the pan ("dry"). IOW, the MYTH. Which of course, is the thing we're all telling you is IMPOSSIBLE to happen, if thought to be based on the cause being, the pump's "volume" rating. Sure, it's POSSIBLE for a pan to be "sucked dry"; sure, it HAS happened; sure, it can happen again; butt NOT because of a "high volume" pump. For OTHER reasons, yeah, maybe; for THAT reason, no. Similarly, it's POSSIBLE, and well and widely known to happen, that a STOCK pan can be inadequately baffled for uses beyond the intended design of said STOCK engine, such that the oil all runs away from the pickup; which does NOT fit the definition of "suck dry". The pan isn't "dry" in that situation; there's still plenty of oil in there; it's just no longer available to the pickup. That's something else altogether besides "suck dry".
So please "explain". I'm sure we'd all find it interesting and informative, one way or another.
THIMK: the ONLY oil that makes it out of the pan and up into the rest of the motor, is that which passes through the bearing clearances, lifters, etc. This is TOTALLY dependent on the clearances themselves, and the oil pressure. All of the oil that the pump gears move butt that DOESN'T pass through those places, goes right back to the pickup side of the pump; IOW, the oil that the gears move that's in excess of what the clearances allow to flow, makes a circuit running around INSIDE the pump. It therefore DOES NOT MATTER what the pump's volume capacity is; the ONLY oil that gets past it, is what the clearances allow.
Your problem is the oil running to the back of the pan and uncovering the pickup. You can demonstrate this to yourself by simply adding a bit extra to the crankcase; maybe ½ quart or so, not enough to rise above the level of the tray in the pan, butt enough to help keep the pickup submerged. If this cures, or at least significantly lessens, your problem, then you have your explanation. Either run the slightly higher oil level all the time, or get a pan with better baffling.
Last edited by grinder11; Mar 28, 2026 at 03:51 PM.











