Oil Leaks !@# Is the L92 rear cover different?
06-07-2010, 08:15 AM
#42
My mistake was not seeing two dipstick holes-- one in the block and one in the pan. If you have a crate block then the hole not necessary for the application will not be plugged. Crankshaft sling will spray the underside of the headers.
01-30-2011, 10:26 PM
#43
Teching In
Join Date: Nov 2010
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
bringing this thread back from the dead.... So after reading all these posts, I'm hoping that I was just having some pressure build up in the crank case and pushed some oil out of the rear main and not that the seal is bad. I have an L92 and the driver's side valve cover vents into the stock location on the intake, the pass I just capped off. No leak till the motor went past 6k rpms. Would this cause enough pressure to leak out the rear main? Is the seal possibly still ok? Final question; if this got on my clutch, am I totally screwed? Obviously I don't want to pull the motor if I don't have to.... but whatever needs to happen.
**edit, I also have an LS1 oil pan.
**edit, I also have an LS1 oil pan.
Last edited by -J-; 01-30-2011 at 11:49 PM. Reason: more info
01-31-2011, 08:22 PM
#44
Happened to me. I ASSumed my seal was bad because the motor had sat for several years, but in reality I deleted the PCV and changed to sheetmetal valve covers that were not vented. On first start, the seal started dripping pretty heavily and I went through pulling my trans to replace it (seal was perfect). After adding breathers to the valve covers, the problem never recurred. I'd try wiping it all down and adding a vent or PCV and see what happens before initiating the trans thrash...
02-01-2011, 02:18 AM
#46
TECH Senior Member
iTrader: (96)
Join Date: Aug 2007
Location: Turnin' Wrenches Infractions: 005
Posts: 24,240
Likes: 0
Received 81 Likes
on
72 Posts
My newly assembled motor is doing the exact same thing as OPs. Starter is wet, oil is flung inside the bellhousing but the converter and flexplate are dry. **** is weird.
My PCV is: stock line from the TB to the front of the passenger intake. Back to valve cover spots connected together by a rubber hose. LS6 valley cover (newer style) running the short hose (GM part) to the intake neck. Is this causing my problem?
My PCV is: stock line from the TB to the front of the passenger intake. Back to valve cover spots connected together by a rubber hose. LS6 valley cover (newer style) running the short hose (GM part) to the intake neck. Is this causing my problem?
02-01-2011, 02:38 AM
#47
TECH Senior Member
iTrader: (96)
Join Date: Aug 2007
Location: Turnin' Wrenches Infractions: 005
Posts: 24,240
Likes: 0
Received 81 Likes
on
72 Posts
OK, the Thunder kit has the valve cover plugs included. They are to plug the two rear hoses on the valve covers. Leading me to think linking the valve covers together is incorrect, a mistake me and the OP made. Im going to disconnect mine ASAP and plug them. Maybe this will fix the oil pushing out of the rear.
02-01-2011, 07:36 PM
#48
The crankcase has to vent, preferably to the PCV system or through purpose-built breathers. If not, maybe the front or rear seal will give or the dipstick will blow out. Ever watch tractor pulls? Granted these guys are jamming 150# plus boost, but their crankcases are pressured up so much the vent tubes look like steam jets!
02-01-2011, 11:33 PM
#49
TECH Senior Member
iTrader: (96)
Join Date: Aug 2007
Location: Turnin' Wrenches Infractions: 005
Posts: 24,240
Likes: 0
Received 81 Likes
on
72 Posts
Whats particular about these situations is that the rear main is dry, and so is basically everything else, yet oil is slung inside the bellhousing. My converter and flexplate are dry as well but literally directly above them almost defying gravity oil hangs from the bellhousing. Obviously its getting pushed out at high rpm only but what is incorrect in the very basic PCV system thats causing this?
02-02-2011, 08:38 PM
#50
Whats particular about these situations is that the rear main is dry, and so is basically everything else, yet oil is slung inside the bellhousing. My converter and flexplate are dry as well but literally directly above them almost defying gravity oil hangs from the bellhousing. Obviously its getting pushed out at high rpm only but what is incorrect in the very basic PCV system thats causing this?
02-03-2011, 07:16 AM
#51
02-05-2011, 08:09 PM
#52
Staging Lane
Join Date: May 2008
Location: Glen St Mary,Fla.
Posts: 97
Likes: 0
Received 0 Likes
on
0 Posts
I'm having the exact same crap,New LSX stroker,FI(Turbo) setup, barely 400 miles on it Dual Catchcans that suppose to help with the pcv ****,But spitting oil out the back upon making boost,Tired of wiping and Cleaning,So yanked the Tranny out today,And found the same ****, rearmain seal relatively clean,Flexplate,converter,etc.BUT the bolts on the rear cover were dripping with oil,wiped everything down reinstalled the flexplate,crank it up ran for 5mins,removed flexplate to inspect rearmain seal and it was clean,So I'll be removing the cover tommorrow to check that O-ring,And I sure hope it's there cause I just paid sum good money to a certain Builder out in Texas to build this motor SURELY THEY did'nt leave it out,So maybe we can figure this out so we can help someone else prevent this..see pics
02-09-2011, 03:02 PM
#53
TECH Fanatic
iTrader: (9)
Join Date: Mar 2004
Location: Pasadena Texas
Posts: 1,318
Likes: 0
Received 0 Likes
on
0 Posts
Interesting! I thought that the more vacuum that you pull on the crankcase, the better. But at high rpm, there is little or no vacuum so a vent would be good. I will try that. Where do you tap this fresh air. In front of the throttle blade so it is not pulled by vacuum? My 90 mm TB has no port to tap into fresh air..
02-13-2011, 06:30 AM
#57
02-19-2011, 11:28 AM
#58
Teching In
Join Date: Nov 2010
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Well so far, I think I fixed my issue. I have the driver's side valve cover into the stock location on the intake and my passenger side has a breather/filter on it. Now as far as where the oil came from.... I pulled the motor thinking I had to replace my rear main. It was bone dry and looked fine, but 2 of my flywheel bolt holes were full of oil. Cleaned everything up and RTV'd the bolts/holes and so far no leaks and the motor has seen approx 6500RPM's. oh, and my clutch is fine.
