2003 6.0 liter chevy, rear main seal question

[John@Outfront]

Hey guys I don't usually work on these motors but I'm doing a rear main seal and want to remove and reseal the large plate at back of motor that holds the rear main seal.  its in a 15 passenger van i have no hoist to raise this thing so my guy is doing it on the ground and only pulled the tranny back 6"  

Question  can that rear plate be removed and resealed with out removing the oil pan or is there a reason i could not?

its a cast aluminum pan

 

[Sandkist]

If it looks like this than yes. Gasket is an aluminum/oring style. You can order a new plate with the seal already installed, new gasket and bolts included.

 

[John@Outfront]

the rear gasket was so crispy we are doing the oil pan as well, now the job is extra easy  thanks

 

[L.R.S.]

 The plate can be removed. The new O ring style gasket come with the tear main seal. I keep a few on the shelf. Also, I have the @CBMrear main seal install tool if you want to borrow it. 

 

[John@Outfront]

 The plate can be removed. The new O ring style gasket come with the tear main seal. I keep a few on the shelf. Also, I have the @CBMrear main seal install tool if you want to borrow it. 

View attachment 38187

View attachment 38186

i assume you mean rear and not tear?  with the plate in hand and able to work on the bench, is there any reason to need the installing tool?

 

[John@Outfront]

i assume i could install the seal into the plate and work the pair on the motor, completely dry seal  i understand?

 

[Mike E]

i assume i could install the seal into the plate and work the pair on the motor, completely dry seal  i understand?

The tool will allow you to install the plate completely centered and if the pan is on you will be able to get it straight. There are a couple ways the plate can get off as there are no alignment dowels on the front or rear plates of the LS engines. If the seal is not centered you will still have a leak. If the plate gets tilted it will leak between the plate and the pan. Just a couple things to look out for as you assemble it. Without the tool you can probably get pretty close as the seal should center the plate on the crank. just make sure the bottom is square to the pan and slowly work your way around to tighten the bolts. Without the tool you would install the seal into the plate on the bench. 

 

[Rockwood]

i assume you mean rear and not tear?  with the plate in hand and able to work on the bench, is there any reason to need the installing tool?

Only the Japanese do silly things like make sure the seal is installed correctly without special tools. :biggrin:

Use the tool mentioned above to center the rear cover, then use the tool to drive the seal on with the plastic center piece still in the seal while driving.

 

[J Alper]

Like Jeff pointed out the seal must be used so the left to right is correct, the oil pan needs to stay on so it will be flush, 

The rear Gasket musted be replaced, if bad it will have oil pressure issues, the oil valley is partially controlled by the front cam plate and the rear gasket, 

If you are in there that far replace the rear barbell also,  hammer in a small screw driver flat head at 45 degrees and it will come out, 

DONT FORGET to put silicone at the corners of the rear cover plate where it meets up with the oil pan, 

Depending on the year, i try to keep the rear cover that comes with the motor, some rear covers are different, the aluminum block covers are different then the iron block, some covers can make starvation issues to the lifters, this is a iron block issue, aluminum block can use any rear cover, Iron blocks dont mismatch, 

 

[J Alper]

i assume i could install the seal into the plate and work the pair on the motor, completely dry seal  i understand?

If you do not do it right, then what is the point,  using the seal to align the rear is fine as long as you remove the oil pan, if not do the job correctly, use a alignment tool, last thing you want is to pull the motor again, 

ALSO THIS IS IMPORTANT, the rear crank / flywheel bolt are drilled all the way through,   you must use a high heat thread sealant, I use a locktite 545,  

you can also use new flywheel bolts with thread sealant already on them, 

 

[ROBERT L]

If you do not do it right, then what is the point,  using the seal to align the rear is fine as long as you remove the oil pan, if not do the job correctly, use a alignment tool, last thing you want is to pull the motor again, 

ALSO THIS IS IMPORTANT, the rear crank / flywheel bolt are drilled all the way through,   you must use a high heat thread sealant, I use a locktite 545,  

you can also use new flywheel bolts with thread sealant already on them, 

View attachment 38229

That some great information 

 

[Jrauscher1]

@John@Outfront At our shop we always order the kit from the dealer with the plate and gaskets ready to go- sometimes the plate warps and creates a leak. Cheaper insurance for us-

 

[John@Outfront]

@John@Outfront At our shop we always order the kit from the dealer with the plate and gaskets ready to go- sometimes the plate warps and creates a leak. Cheaper insurance for us-

thanks guys, so the rear seal kit i ordered comes with the plate and gasket already assembled, i have pulled the pan too because gasket is rear hard. i will just aling the part flush with pan and have the seal self center itself.  the new seal and plate looks like a normal viton seal with grease and its a GM part, do they retro these to use a regular seal?

what does the dog bone thing do and seal?.  from the looks if the oring goes bad is it bypassing the oil cooler?

 

[Rockwood]

thanks guys, so the rear seal kit i ordered comes with the plate and gasket already assembled, i have pulled the pan too because gasket is rear hard. i will just aling the part flush with pan and have the seal self center itself.  the new seal and plate looks like a normal viton seal with grease and its a GM part, do they retro these to use a regular seal?

what does the dog bone thing do and seal?.  from the looks if the oring goes bad is it bypassing the oil cooler?

Seals either end of the oil filter passage. It only plugs holes left on either side as part of the block machining process and doesn't move.  If the seal dies, oil will bypass the engine and low oil pressure is the result.  You can get aftermarket versions made of aluminum for pretty cheap, but their tolerances are much tighter so can be a bit finicky to install (might need light sanding).

@J Alper Nicely done, completely forgot about those parts.  I removed mine with a drywall screw: just drill a small hole, screw a drywall screw in and pull it out with that.

 

[John@Outfront]

im not a v8 guy but im thinking if the part was not there it would "not" be low oil pressure but the oil flow would not be forced through the cooler if there was one.  without an oil cooler there is a block off plate that connects the two holes in the same way i would guess not having the plug would do

correct me if im wrong

 

[J Alper]

Seals either end of the oil filter passage. It only plugs holes left on either side as part of the block machining process and doesn't move.  If the seal dies, oil will bypass the engine and low oil pressure is the result.  You can get aftermarket versions made of aluminum for pretty cheap, but their tolerances are much tighter so can be a bit finicky to install (might need light sanding).

@J Alper 

I agree, i do the aluminum but clean the china ones up on the lathe, the Improved racing is perfect, but most do not want to spend the money,  

im not a v8 guy but im thinking if the part was not there it would "not" be low oil pressure but the oil flow would not be forced through the cooler if there was one.  without an oil cooler there is a block off plate that connects the two holes in the same way i would guess not having the plug would do

correct me if im wrong

 The barbell had issues, some sizes where wrong and split the o ring or pushed out, the new ones are all the correct sizes, they are around $4,  so it is just best to change it, 

The Flywheel bolts are torque to yield, plus have sealant on them, also about $18 for the hardware, best also to change it,   

If yo are pulling the pan,  use silicone on the bottom of the motor where the covers meet the block, on the front and rear cover, 

 

[J Alper]

If you are that far into the motor,  i typically pull the front balancer, it has little notches and comes right off, 

The front seal is about $21 they are common to leak, 

If you do pull the front balancer, Heat the bolt up with a torch for about 1 minute to 2 minutes, and it will come right off,  I torque it to 220 ft lbs,   

 

[77charger]

Some good info reading here.I may have to replace a front seal on my 2500hd 6.0 pretty soon.

 

[John@Outfront]

Seals either end of the oil filter passage. It only plugs holes left on either side as part of the block machining process and doesn't move.  If the seal dies, oil will bypass the engine and low oil pressure is the result.  You can get aftermarket versions made of aluminum for pretty cheap, but their tolerances are much tighter so can be a bit finicky to install (might need light sanding).

@J Alper Nicely done, completely forgot about those parts.  I removed mine with a drywall screw: just drill a small hole, screw a drywall screw in and pull it out with that.

i stand corrected, if the o-ring blows it opens a passage from mail galley to the oil pan via the inside of rear cover.  thanks for all your V8 help, car left very clean and the new GM part with cover, seal and gasket assembled had a conventional seal in it