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Discussion Starter #1
I recently was gifted the truck described in the subject. It has a persistent oil leak. The oil sending unit was giving a 100% reading, so I replaced this sensor. The valve cover gaskets had a slight leak, so I changed both. In both cases, the new installs are dry. At this point, I still have an oil leak that seems to come from either side of the oil pan. The bolts on the starter are soaked, and the oil cooler mount (not present) on the opposite side is also soaked. I suspected the leak was from a failing rear main seal, but the inside of the bell housing is bone dry along with the flywheel. Any recommendations on next steps?
 

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Check all the oil pan bolts. Anything coming from the front and blowing back toward the starter etc. Do you have an oil cooler unit? They are pretty notorious for leaks.
 

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Discussion Starter #3
I tightened the oil pan bolts all around. There was some play in the bolts but not much. Still dripping on either side of the pan. An oil cooler is not present, just a plate.
 

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Check again to see if the new oil pressure sender unit (and adapter if you have one) is not leaking since it will flow down both sides of the block. It is possible that the oil pan gaskets are bad too. Did the leak slow down after snugging up the oil pan bolts and or the valve covers?
Only other option I can think of is to clean off all oil drips and add a leak tracing additive (fluorescent dye) to the oil. Then use ultraviolet light to find the leak.
 

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Discussion Starter #5
Each of my repairs have improved the oil leak progressively. The new oil sending unit and valve cover gaskets helped. The oil pan bolts were a little loose, but even after a slight tightening, the car was still dripping oil. I found that the oil pan was weeping around the edges, so I replaced the oil pan gasket, which further dried up the area. I still have oil dripping down either side of the bell housing and through the weep hole below the flywheel. I believe the issue is directly related to the rear main seal and/or the gasket for the back cover. At this point, I am above my “pay grade” in terms of skills and tools, so I am going to take the truck to a shop to drop the transmission and fix these last areas. Has anyone tried Lucas Engine Oil Leak Stop? Will this help, or should I skip this step and go to the mechanical solution? Any guidance would be appreciated.
 

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That's a tough call to replace a $10 rear main oil seal and $$$ labor cost to keep it dry.
So what's bothering you?
Is it the oil drips in the driveway?
Or the frequent oil level checks and topping up oil?

My 2001 suburban 5.3 has 285k miles and has been consuming oil since new. About 1 quart between oil change. So I check the oil level every fill up anyway
It developed a rear main seal leak around 230k miles it drips on my driveway.
Instead of replacing the oil seal, I just extended the skid plate near the bell housing and zip tied a rag to absorb the oil drips. So far, my driveway is oil free. LOL.
I don't use stop leak additives.
Good luck.
 
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LOL.
I just have a shallow pocket being retired, and would rather put money on gas and tires and important preventive maintenance.
$700 labor to replace a $10 oil seal on my high mileage 2001 Suburban is just too hard to swallow, which explains the zip tied absorbent rag. LOL.
 
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