Changing the main crank oil seal.(updated)

[e30_Turbo]

My baby is leaking her life blood all over the road and IÔš've been assured itÔš's the crank oil seal, gearbox end.
Now itÔš's not a job I can do on the drive with me spanner and ramps so IÔš've been out and about to get some quotes. IÔš've ordered new crank oil seal and gasket from the stealers, at a ok price too. (Ԛ£27.26)

Now has anyone had this done before? And how much did you pay?

[JoeP]

My baby is leaking her life blood all over the road and IÔš've been assured itÔš's the crank oil seal, gearbox end.
Now itÔš's not a job I can do on the drive with me spanner and ramps so IÔš've been out and about to get some quotes. IÔš've ordered new crank oil seal and gasket from the stealers, at a ok price too. (Ԛ£27.26)

Now has anyone had this done before? And how much did you pay?

The one I'm looking at has this, it's only losing about half a pint a month though. It's a proper gearbox out jobby. I'd also be interested to hear how much it costs.

[Karan]

hmmmm mine also appears to be doing this now--well this or the gbox input shaft seal...

Karan

[telski789]

its pretty obvious the prop and box have to come out,after that its plain sailing,just undo the sealhousing (a few bolts) yhen take it off and replace the seal into the housing,then back on,as long as your fine with taking ur prop and box off,its fine,half a day jobby

[Ant]

Mark cheak you emails dude

Karan the leak could be related to your oil smoke at high RPMs mate, you checked the brethers out ???

[e30_Turbo]

Ant, Which email add dude? work?

And I've had a quote from a local garage and they will do the labour for Ԛ£130.00 + vat + parts. Not bad me thinks.

And Karan, mine is leaking from the seal between gearbox and engine, there is a small slot, like a coin slot and it's dripping from there.

[Karan]

Mark cheak you emails dude

Karan the leak could be related to your oil smoke at high RPMs mate, you checked the brethers out ???

oh sh1t

now u mention that... i ahve had another possibly related problem..... occasionally when i open the bonnet... i find the dipstick has popped out

what do u reckon is going on, i havent a clue....-r u sayin the breather off the rocker may have split...., how would this cause smoke?

heeeeeeeelp, i dont wanna be rebuilding the head for no reason

cheers dude
Karan

[Demlotcrew]

Mark cheak you emails dude

Karan the leak could be related to your oil smoke at high RPMs mate, you checked the brethers out ???

oh sh1t

now u mention that... i ahve had another possibly related problem..... occasionally when i open the bonnet... i find the dipstick has popped out

what do u reckon is going on, i havent a clue....-r u sayin the breather off the rocker may have split...., how would this cause smoke?

heeeeeeeelp, i dont wanna be rebuilding the head for no reason

cheers dude
Karan

Shit thats not a good sign at all!

[Ant]

classic excessive crankcase pressure Karan.

check the vertical tube for blockages, the port between that and the head and the suction feed running from the rocker cover to the TB.

as a test block the TB fitting off with a stub of hose and route the main breather into a small catch tank( coke bottle) remember to leave a few holes in the top to let it breathe, see how much oil is puked out under normal driving.

I'm thinking some ring blow by is occuring dude,

keep us posted M8

[Karan]

dude u have scared the living sh1t outta me-please explain- before i kill myself

[Karan]

classic excessive crankcase pressure Karan.

check the vertical tube for blockages, the port between that and the head and the suction feed running from the rocker cover to the TB.

as a test block the TB fitting off with a stub of hose and route the main breather into a small catch tank( coke bottle) remember to leave a few holes in the top to let it breathe, see how much oil is puked out under normal driving.

I'm thinking some ring blow by is occuring dude,

keep us posted M8

cheers dude

so i check the rocker to tb hose,,, but whats the vertical tube u mentioned


oh so ure saying that cos of the high crankcase presure cos of shagged rings.... oil is comin out the breather and then into the engine and burnt via the tb??

could i really have ring wear even though the engines only done about 80k miles???

Karan

[Karan]

ok
i went and checked the rocker to tb pipe and its not blocked at all!

there is oil present in the tb... but not as much as say my iS had on there.. but i guess that would get sucked in to the engine anyways...

i think im gonna have to get it compression tested, and if theres low comp i guess its worn rings, or could it be the headgasket...
how much is it gonna cost to get new rings and a rebuild

also why did this happened--is it cos of shoddy engine mapping at bexleys and the car running lean, or cos of very hard driving- i never gun i ttil its cold..

cheers
Karan

[Demlotcrew]

I would say cheap oil.

Andrew

[android]

Overfilling the oil can cause crankcase pressurisation. Make sure that you don't go over the top mark on your dipstick. Happened to my 325. seems to be OK now.

[Karan]

hmmmm

i thought this may be the case... as i do a lot of miles and fill it up regulary as a result of shagged stem seals i may have gone over the top slightly....

just gonna keep on running it as is and see if the popping dipstick corresponds to just after when i fill it up.. will also get a compress. test done and do the 'ant test'

[Demlotcrew]

Overfilling the oil can cause crankcase pressurisation. Make sure that you don't go over the top mark on your dipstick. Happened to my 325. seems to be OK now.

How so?

Andrew

[Karan]

overfilling will reduce air volume in the crankcase therefore increase the pressure on running causing dipstick to pop out!

compression test or 'ant test' are the only way to go methinks, i will just only ever top up by 0.5l, not 1 litre like i have been recently, if it continues, ill check the vertical breather tube if its blocked, then as i'll be doing the stem seals anyway i'll just have remove the whole thing and get the rings changed, bores rehoned and pistons all cleaned up- should cost less than Ԛ£300 for the bottom end machining which is ok i guess and not the end of the world.... the 2.7 will live on!!!

cheers
Karan

[Ant]

comp test will tell all Karan.

the catch tank trick is a quick way to asses how high your crankcase pressure is, its a good indication of the state of the compression rings M8

fit the catch tank and go for a blast, see if the smoking @ rpms has vanished . then worry about the rest of it M8

my earlier post was not to worry you , just info I felt would be relevant and hopefully of use.

[Karan]

cheers ant...

i wasnt worried bout ure comment but more about the demlotcrew 'sh1t thats not a good sign' thread

helps greatly appreciated! will get the thing comp tested for sure when i gte back home from uni (havent even got any bloody tools here!)

cheers
Karan

[Demlotcrew]

overfilling will reduce air volume in the crankcase therefore increase the pressure on running causing dipstick to pop out!

compression test or 'ant test' are the only way to go methinks, i will just only ever top up by 0.5l, not 1 litre like i have been recently, if it continues, ill check the vertical breather tube if its blocked, then as i'll be doing the stem seals anyway i'll just have remove the whole thing and get the rings changed, bores rehoned and pistons all cleaned up- should cost less than Ԛ£300 for the bottom end machining which is ok i guess and not the end of the world.... the 2.7 will live on!!!

cheers
Karan

Having more oil in the sump will not raise the crank pressure. The breather pipe creates a small vacume inside the crank case and head.
The only bad thing about having too much oil, is the crank can foam the oil with its rotation and cause a drop in oil presure.

Andrew

Andrew

[Ant]

actually this topic is quite timely as I know I'm gonna have some fun with a pressurised crankase in the next few days

my soloution is easier though....... apply a T3 turbo to the vent pipe and suck the pressure down again.

I have zero oil leaks @ the mo and the block is bone dry everywhere so its gonna be interesting

[Karan]

actually this topic is quite timely as I know I'm gonna have some fun with a pressurised crankase in the next few days

my soloution is easier though....... apply a T3 turbo to the vent pipe and suck the pressure down again.

I have zero oil leaks @ the mo and the block is bone dry everywhere so its gonna be interesting

that thing's gonna rock!!

Karan

[SeamanStaines]

It's fairly unlikely to be the rear crank oil seal on an M20. It's much more likely to be a shagged sump gasket which is very common on the M20. The gasket pops out at the back and oil leaks from the bellhousing area.

These are a complete bastard as well. Exhaust downpipe off, AFM hose removed, loosen the radiator so it lifts with the engine, both engine mounts and lift the engine with a crane, watching the wiring etc. The sump might clear the oil pump, it might not meaning removing the oil pump with the sump.

Real fun.

[e30_Turbo]

It's fairly unlikely to be the rear crank oil seal on an M20. It's much more likely to be a shagged sump gasket which is very common on the M20. The gasket pops out at the back and oil leaks from the bellhousing area.

These are a complete bastard as well. Exhaust downpipe off, AFM hose removed, loosen the radiator so it lifts with the engine, both engine mounts and lift the engine with a crane, watching the wiring etc. The sump might clear the oil pump, it might not meaning removing the oil pump with the sump.

Real fun.

So is there a way to determine which one of the two possible culprits is actually leaking?

[Karan]

clean it up with gunk or brake cleaner really thorought-then inspect it later to try and pinpoint the source of the leak...

[e30_Turbo]

Thing is leak is coming from the slot in the bellhousing/engine join. Can't see where it's leaking from inside, either way it sounds like I need to have the box off and have a look. Better let the garage have it for the day to have a look then....

[SeamanStaines]

Leaking from the slot in the bellhousing - classic case of the sump gasket gone. Take the front bit of the bellhousing off (four 13mm bolts going up into the block and about 4 torx bolts going in from the gearbox bekkhousing) and clean it up in there. Shine a torch up there and you will probably see the sump gasket has been forced out.
I did my 320i on Friday that was so bad, it leaked oil when the engine wasn't running but was jacked up at the front. It was absolutely pissing out.

Fixed that and then the fan went through the radiator (engine mount), cutting two large holes in it and dumping the coolant.
Fitting another rad soon to see if the head's buggered...........

Anyway, tell the garage it's more likely to the the sump gasket at the back.

[Toby_Unna]

Karan if it makes you feel any better (!) the old 3.5 that used to be powering my 335 is now in bits in my cellar and it was not in a happy state. one slightly bent and sticking valve, all burnt exhaust valve seats, an inch missing from one compression ring with corresponding groove in that bore, and four black inlet ports vs 2 shiny silver ones. gawd only knows what was going on there, but it'd done 160k+ miles and there were still clear honing marks on the bores so i guess someone'd had it apart before.

and i was planning on spending Ԛ£Ã”šÃ‚£Ãƒ”šÃ‚£ getting the fcuker rolling roaded to try to pinpoint the high rpm power loss problem. that would have pissed me off!

got a comp tester if u need to borrow one dude

[Karan]

that would be great--but ure a bit far away lol

ure engine sounds like it was proper shagged!!!lol

i'll get mine comp tested nxt week--i have a feeling the dipstick is only popping out cos of mway runs with vibrations as it never comes off otherwise.....

cheers anyway

Karan

[GavinJ]

Can i join in,


Mines developed a large leak which looks to be coming from where the gearbox and engine bolt together, if its parked uphill you can see it dripping......

Pisses out whilst its not running, could either be sump gasket or rear crank seal....

[Karan]

hmmm that looks like quite a lot....

[GavinJ]

sure is and thats my nans drive so she wasn't very impressed!! it was only parked for about an hour or so aswell, its a constant drip if its parked up hill but on the flat it hardly drops any.

[Karan]

i think ures is very likely to be the sump gasket as andy said.... i doubt a leaky crank seal would leak like that at rest...

[Hammer1]

Yep always check gasket first.I had the same problem on my old 320i touring..I part repaired the rear of the sump gasket and i didnt even take sump totally off,i just dropped it down a inch or so and repaired in situ.

[e30_Turbo]

Got her back from the garage today, seems SEAMAN STAINES was on the right track . My sump gasket has popped out and is leaking oil. So new gasket on order and a play at the weekend is planned.

Big thanks to SEAMAN STAINES for putting the theory forward, I bet I would have been charged for the labour aswell as the parts if the had of found this when attempting the crank seal.

So to all you leaking e30's, get it checked!!

( I managed to get the check for free too )