I learn something new about LS engines all the time..
 

Life is an educational experience.. lol

Yesterday I learned that the bolt holes in the back of the crank, for the flywheel are NOT blind holes but go through to oil...

Not sure why they would do this unless it was just to make sure the holes wouldn't hydrolock.. but that seems unlikely.

Were ready to put Penny's LS engine back in, added oil and thought we had a massive leak from the rear seal.. tilted the engine to check and oil came out the crank holes...

Go figure

That has to be an aftermarket deal. I bet you're not the first to get fooled by that one.

actually, out of curiosity I just went out and looked at my stock LQ9 6.0 crank................... drilled through. Of course I don't pull the motor full of oil, or have it slanted at a severe angle so I wouldn't have noticed it.

Jody

Wow, I bet you'll be using a little thread sealer from now on.

Well we had pulled the engine to fix the oil leak from the rear cover.. once repaired we thought we would add oil and tilt the engine back "just to see"

We also put the oil into the open valley area (cover was off for lift plate).. I guess doing it that way causes oil to come out the crank holes :shrug:

when oil started pouring out we were like "WTF!!".. lol.. at first we thought it was a bad seal then we saw it was coming out of the flywheel bolt holes.

Doh!

I still think it's odd that they did it that way, must of had a reason.

The factory Torque To Yield bolts come with green thread locker.. or maybe it's there to seal the oil passages and not really to lock the bolts?

That's the only logical conclusion. Loctite makes a decent sealer. I used red on my old power steering pump inlet and it never seaped. Perfect example of an aftermarket component that doesn't meet factory specs. I'm sure the flywheel bolts you used said nothing about using a sealer or loctite. I gues the blame lies somewhere in the middle .That's about the best thing it could've been though. I like when the solutions are easy! :unibrow:

Well, I only use GM TTY factory flywheel bolts.. in fact Centerforce says you can't use aftermarket bolts like ARP and such.

The GM bolts have a green sealer/locker on them already.. which is good since I wouldn't have thought to do it before I knew the holes went to oil.

The leak I pulled the engine to fix wasn't from the flywheel bolts.. it was from the back edge of the Canton pan.

Anyways, this was just and FYI to the LS engine fans out there. I suppose if you use aftermarket flywheel bolts then some locker or sealent would be a good idea.

Gotcha, I missed the point of the thread completely. :D I thought it was the source.

I love learning things like this, ...especially when it's from someone else. ;)


Thanks Steve.

hmmm i used arp bolts when i was putting my project together, i hope im not in for trouble along in the future....

I really, really, really wish I read this yesterday. I just finished installing the engine and transmission into the car, without any sealant. I used ARPs.

I have been pulling flywheels like crazy off these motors and never noticed this either. Great thread, Thanks!

If they aren't for oil circulation my 2nd bet they aren't blind to make cleaning easier, those blind holes like to hide crap that if it ever comes loose likes to kill things in engines :D

Dont worry if they are torqued correct your fine. I run ARP and they have torque specs for oil, locktite and moly lube.

Just a FYI if you replace the roller pilot bearing dont use the old grease and drive pin method. It sits in a through hole thats has a plug similar to a freeze plug, you will drive that plug into the engine.