: Crankcase half leak?



Jailtime
04-07-11, 04:24 PM
Got my STS back from the dealership, and the tech wrote "engine crankcase half leak" in the notes. What's the deal with that? I'm not going to get too concerned, since I only need to add a quart of oil about every 2000 miles.

But is this something that can get worse and cause some sort of catastrophic failure?

EDIT: Not liking what I'm seeing after some quick searching.

Submariner409
04-07-11, 05:52 PM
A halfcase seal repair requires dropping the drivetrain out of the car. Complete engine disassembly. The book labor on this particular job is 20 hours at a dealer who has all the special tools.

That $2,800 +++ job will buy a LOT of 5W-30 engine oil.

If it ain't broke, don't fix it................and a halfcase leak/weep will NOT cause catastrophic failure..............no way to tighten any nuts or bolts, either. The seal is not a gasket - it's a silicone "O-ring" set into machined grooves in the block. The repair calls for a new GM RTV (Room Temperature Vulcanizing......) rubber application to squeaky clean case mating surfaces.

vincentm
04-07-11, 06:39 PM
Dealership i took mine to said the same thing, in that it left a puddle of oil in their shop, funny thing is it doesn't do so when i park mine in my shop, no oil spots whatsoever. When i told them that they had no answer.

Jailtime
04-08-11, 01:38 AM
I'm not the least bit concerned about the leak then. I don't care about the minor drip on the garage floor. Seems like a really common issue after searching, and almost everybody decided to let it go.

andy396ss
04-08-11, 08:25 AM
Submariner409, when you say complete engine disassembly, do you mean *complete* or can the heads & intake stay on?

Submariner409
04-08-11, 09:12 AM
You could do just the halfcase with the engine inverted - there's nothing up top to prevent that - but most would at least check the chain tensioners and slippers, and some would want to check the (pre-2000) flat tappet cam followers and cams for wear.

The "complete disassembly" sort of assumed the OP would want to do a stud job (at even greater expense) lest he have to pull the engine out again.

NHRATA01
04-08-11, 10:48 AM
A halfcase seal repair requires dropping the drivetrain out of the car. Complete engine disassembly. The book labor on this particular job is 20 hours at a dealer who has all the special tools.

That $2,800 +++ job will buy a LOT of 5W-30 engine oil.

If it ain't broke, don't fix it................and a halfcase leak/weep will NOT cause catastrophic failure..............no way to tighten any nuts or bolts, either. The seal is not a gasket - it's a silicone "O-ring" set into machined grooves in the block. The repair calls for a new GM RTV (Room Temperature Vulcanizing......) rubber application to squeaky clean case mating surfaces.

Yeah mine does it too. Between the burning and the leaking, I just keep adding oil.

But as an engineer...ugh what a crap design choice. I guess that was the late '80s way of adding more crank support and block stiffening. Like a half step up from the traditional SBC main design but prior to the LSx where instead they case the block with a deep skirt, which still provided the lateral support on the main caps and block reinforcement in a more leak-free package. Kind of a nifty way of seeing the historical progression in GM powertrain engineering though.

johnny kannapo
04-09-11, 01:55 AM
I have a half case leak possible or rear seal leak developing after sitting all winter. I won't know the leak rate until I start using the again. I can't stand leaks and need to weight the severity of this new leak before I jump into a extensive repair.

My big question is, do the main bolts have thread issues in the same manner & frequency as the head bolts?

drewsdeville
04-09-11, 03:13 AM
Yeah mine does it too. Between the burning and the leaking, I just keep adding oil.

But as an engineer...ugh what a crap design choice. I guess that was the late '80s way of adding more crank support and block stiffening. Like a half step up from the traditional SBC main design but prior to the LSx where instead they case the block with a deep skirt, which still provided the lateral support on the main caps and block reinforcement in a more leak-free package. Kind of a nifty way of seeing the historical progression in GM powertrain engineering though.

This and the dumbass external coolant crossover, which sounds like it's another relatively frequent problem. In this aspect, the Northstar began to show it's age quickly after debut as casting the crossover directly into the block became a more common implementation (at least on higher end engines).

johnny kannapo
04-09-11, 11:09 AM
The coolant crossover isn't really the problem. The gaskets are poorly engineered only in that they desinegrate after 8 or 10 years.

drewsdeville
04-09-11, 09:03 PM
The coolant crossover isn't really the problem. The gaskets are poorly engineered only in that they desinegrate after 8 or 10 years.

True. But the point is, as other manufacturers realize, the external crossover (or using the intake manifold as a crossover...ask any GM V6 owner) just creates more potential leak points. Casting into the block eliminates that possibility...less gaskets to leak.

Speedygman
04-09-11, 10:21 PM
A halfcase seal repair requires dropping the drivetrain out of the car. Complete engine disassembly. The book labor on this particular job is 20 hours at a dealer who has all the special tools.

That $2,800 +++ job will buy a LOT of 5W-30 engine oil.

If it ain't broke, don't fix it................and a halfcase leak/weep will NOT cause catastrophic failure..............no way to tighten any nuts or bolts, either. The seal is not a gasket - it's a silicone "O-ring" set into machined grooves in the block. The repair calls for a new GM RTV (Room Temperature Vulcanizing......) rubber application to squeaky clean case mating surfaces.


You might be surprised what a good cleaning with brake clean and then some Super Glue in the split of the case where it is seeping? Has worked on other mild oil seepage.

ejguillot
04-14-11, 11:45 AM
Might work, IF you can get to the leaking area with the engine in the car! The firewall side is pretty much inaccessible with the engine in the car. I'm watching this with some interest, as I have an oil leak that once in a while results in visible oil smoke coming from the firewall side of the engine block.

Should have resealed it when I had the engine out for the head stud repair last year, but was running short of time and funds and the engine wasn't really leaking then.

tjwhite721
08-08-14, 11:31 AM
I think using adhesive from the outside might work if you can add something around the oil pan or crankcase to help it bond. Maybe a piece of rubber or an aluminum strip.