Rear main seal leak?

[HACK BLOCK]

when for an oil change and noticed a leak. I'm guessing rear main seal but I don't know for sure. let me know what u guys think

 

[OR VietVet]

While that certainly could be a rear main seal leak, it could also be the plate the oil filter attaches at or the block off plate or plate that the oil cooler lines attach at. That plate is simple to replace and I recommend doing the entire plate if you have no oil cooler lines and don't do just the seal. The available plates are billet and work great.

Sample at Amazon: https://www.amazon.com/Whip-Billet-...ine+oil+block+off+plate&qid=1614799921&sr=8-3

Seal at RA: https://www.rockauto.com/en/moreinfo.php?pk=6576836&cc=1446824&jsn=2253

You gave no engine size so I looked up as a 5.3.

May even be something from above leaking that is draining down.

I think there is even a chance of a knock sensor seal leaking.

 

[89Suburban]

You can pop that little inspection cover off the bell housing and look in there with a flashlight at the rear of the block to see if it is leaking in there. Otherwise it could be the block off plate gasket above the oil filter, the pan gasket, valve cover gasket, or valley cover gasket.

 

[iamdub]

I don't think that's a block-off. I think he has the oil cooler. A block-off isn't square like that.

The only way to pinpoint the source(s) is to clean it off and drive for a day or so, checking it periodically. As Paw Paw said, look between the flex plate and rear cover to see if there are any trails. Unless it's a huge leak, you'll need a bright flashlight, so do bother trying with the light on your phone. I'd spray it off with a couple cans of brake cleaner to clean it off really quickly. Wear goggles and/or face shield.

 

[HACK BLOCK]

yea I think I'll spray it with some carb cleaner cause that's what I have right now and check it every few days. I won't have access to a lift, only the bottle jack that comes with the truck

 

[wjburken]

My money is on the oil cooler plate leaking. The big drop of oil that is on the bottom of it probably didn’t come from a rear main leak. Not saying the rear main isn’t leaking, just that I think the oil cooler block is leaking as well.

 

[OR VietVet]

If has the lines and is the oil cooler plate, the seal could be the link I posted for whichever engine it is.

 

[Foggy]

I would use brake parts cleaner.. It leaves NO Residue.. Carb cleaner is very
corrosive and harsh.. you don't want that near stuff that you aren't replacing

 

[iamdub]

Super Tech brake parts cleaner from Walmart.




The can looks like this, but says "Brake Parts Cleaner"

 

[HACK BLOCK]

I always figured carb cleaner is better or things like oil that would possibly be found around the intake and throttle and brakes cleaner is better for things found around the brakes and suspension like dust and grease. it's whatever no big deal