rear main seal replaced.. still leaking

[96 Calais]

oil still dripping from around the rear main seal, had it replaced 2 weeks ago (seal was definately leaking before).. took it back & im assured it's not coming from the rear main although it's dripping from the same spot (back of engine infront of auto trans).. no oil around the rocker covers at all..

could be the sump gasket maybe?

would it drip from the same spot if it was the sump gasket?

sure, it's only a drip at the moment, but it isn't suppose to drip & it's only going to get worse?

Other than the general age of a car what can cause leaks?

200,000km's 3.8L ecotec if that helps.

I don't have a great deal of knowledge about car's but im learning fast & hope to put some input back into these forums in time
thanks again in advance for your help.

[Claudy]

I'd say sump gasket man ay

[azzfox]

Sump gasket, oil plugs (rare I'd say), cam or balance shaft welch plug. Or they may have scored the crank taking the seal out.

[96 Calais]

no real way to tell without taking it apart I suppose?

[Claudy]

Id replace sump gasket first coz it's not that hard to do and it's probly due for new one by 200,000kms anyway

[Cheap6]

What, exactly, was replaced? The rear main seal sits in a carrier that is sealed against the back of the engine block by a gasket. The lower part of the carrier also forms the rearmost part of the seal to the sump gasket. If the seal (to the crankshaft) was the only thing replaced, those areas may still be leaking.

It's been a while since I've looked at one but if I recall correctly the carrier is not located on any dowels on the back of the block. If the carrier was removed and refitted, or replaced, the carrier may not have been set up in the correct location. There are special tools required to do this in order to ensure that the carrier lower face sits flush - flat and level - with the lower part of the block and the seal is concentric with the crankshaft.

It may simply be that there is oil residue left higher up from the old leak. First step would be to wash the underside of the engine, inspect to ensure that it is clean then drive and reinspect and go from there.

The front seal in the trans. has also been known to leak.

[RX25SE]

These things are an abomination.
I have replaced the seal/housing assembly with the upgraded one from GM (including the sump gasket) and it still leaks.
A mate and I did his car 3 times using old and new style seals and replaceing the housing (he had a centering tool machined) and it still leaks.


I will attempt mine once more only, if it still leaks I'm going to sell the useless POS.

[96 Calais]

hey cheap6, as far as i know whatever is included with a rear main seal kit was replaced. it's under warrenty so if it's still leaking from there they can redo it.
she only started leaking about 4 weeks ago, well thats when i noticed the smell of burning oil at least.. the exhaust and sump was covered in it. having it still leak really bugs me because it shouldn't be leaking. it could be leaking from around the sump gasket i suppose but like you said it could just be left over oil which has slowly dripped down, ill clean it up today and go from there.

ive spent to much on it to sell RX25SE, well not the engine but the rest of the car.. i'd put a different engine in it before I sold :P

[RX25SE]

ive spent to much on it to sell RX25SE, well not the engine but the rest of the car.. i'd put a different engine in it before I sold :P

Fair enough.

I meant MY usless POS.

[Cheap6]

I just thought of another possibility. Is there (on both/either cars ^) any reason for a build up of crankcase pressure eg. a blocked/sticking PCV valve or blow by from engine wear?

(The PCV valve is between the LIM/runners and the UIM/plenum.)

[pjdm1980]

I remember someone saying that if the buick/eco V6's don't get regular oil changes that the grit/dirt build up can make a wear mark in the crank were the seal sits and you have to move the seal or machine the crank.

[RX25SE]

PCV works fine. I cleaned it out when I did the manifold gasket.
Oil is changed every 5000km.
No score marks in crank. Only has 170k on it.

Funny thing is VT have basically the same setup (different sump and gasket) and they have far less problems, and seem to run better too.

Go figure???

[peterg2121]

I remember someone saying that if the buick/eco V6's don't get regular oil changes that the grit/dirt build up can make a wear mark in the crank were the seal sits and you have to move the seal or machine the crank.

this is partially true i work as a mechanic and what happens is the seal goes hard and cuts a grove into the crankshaft so when you go put the new seal on it leaks again the way u fix it without machining the crankshaft is you can buy the right size sleeve to fit over it and fit a seal size slightly bigger its tricky but i work as a mechanic and have done it a few times before

[nathanVY]

this is an ecotec rear main


when done PROPERLY the ENTIRE THING should be replaced, the new part looks like this


I know a lot of mechanics do it dodgy and just replace the rubbers, the plate its-self is often warped (mine was)

[RX25SE]

this is an ecotec rear main
when done PROPERLY the ENTIRE THING should be replaced, the new part looks like this


I know a lot of mechanics do it dodgy and just replace the rubbers, the plate its-self is often warped (mine was)

Is that the upgraded unit with the flat seal (no garter spring)?

[nathanVY]

Is that the upgraded unit with the flat seal (no garter spring)?

not exactly sure sorry

[pieces]

Im in the same boat as others I have a slight oil leak not a big issue . The main problem is coolant leaking and the self refilling of the radiator fails to happen due to this . The temperature warning comes on intermittently due to air in the cooling system . What puts us off doing it our selves is the alignment of the seal plate me and a mate can do it but we dont have the special tools. Ive read all the post here and haven't seen a way of doing it with out the special tools . Any advise would be greatly appreciated .

I rang Holden and they want $1,000 to do it ouch .

[seq4x4]

I did mine fine. No special tools. Not one leak from it since. $20 for the rear main seal, $21 for the rear main plate seal (couldnt find another plate) and $20 for the gasket. If its still in good nik the bolts will have sleeves on them with locate the plate into alignment. However, all you have to do is make sure it lines up correctly.. Do not use sealant. Youll have to drain oil and coolent to do it.

[maldotcom2]

It's been a while since I've looked at one but if I recall correctly the carrier is not located on any dowels on the back of the block. If the carrier was removed and refitted, or replaced, the carrier may not have been set up in the correct location. There are special tools required to do this in order to ensure that the carrier lower face sits flush - flat and level - with the lower part of the block and the seal is concentric with the crankshaft.
.

Can you elaborate on this? What tools are there to align the seal with the main journal? Not being a smart ass, just curious.

[vsv6dude]

Do you have excessive crankcase pressure contributing to the leak ?

[seq4x4]

Can you elaborate on this? What tools are there to align the seal with the main journal? Not being a smart ass, just curious.

About $300 for some plastic aligning tools. I remember finding them once for sale. I spat chips when i saw the price and did the job without them. If your really that keen ill see if i can find them again.

[pieces]

I did mine fine. No special tools. Not one leak from it since. $20 for the rear main seal, $21 for the rear main plate seal (couldnt find another plate) and $20 for the gasket. If its still in good nik the bolts will have sleeves on them with locate the plate into alignment. However, all you have to do is make sure it lines up correctly.. Do not use sealant. Youll have to drain oil and coolent to do it.

Bursons have the kit which includes the plate for around $60 . When you think about it the seal should self center as long as you don't pull it around while tightening the new plate . Also do you use sealant at the bottom of the cover where it meets the sump . ??

cheers

[Reaper]

lol. Didn't read anything but the title however............. Either you did it wrong or the leak is from else where. Impossible to diagnose properly over the internets.


Reaper

[seq4x4]

Bursons have the kit which includes the plate for around $60 . When you think about it the seal should self center as long as you don't pull it around while tightening the new plate . Also do you use sealant at the bottom of the cover where it meets the sump . ??

cheers

Nah i never added sealant there as i use a cork gasket.

[pieces]

Nah i never added sealant there as i use a cork gasket.

Thanks for your help so far . Looks as tho you replaced the sump gasket at the same time ?? I was trying to avoid doing that .