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Omega Help Area => Omega General Help => Topic started by: Jimbob on 07 February 2017, 16:33:01

Title: Unidentified oil leak
Post by: Jimbob on 07 February 2017, 16:33:01
Well Big blue is crying black tears...

Every morning there is a roughly 10cm round pool of oil underneath that appears to have dripped off the bell housing bolts.

Cannot see where its coming from underneath
Stripped down the top end to oil cooler level,

There are what I would call grimy bits around oil filler, edges of cam covers, the odd cam bolt, Plug wells all dry
Nothing I can see that would account for the amount we are losing.

Anyone any ideas how / what to check next?
I'm REALLY hoping we are not talking rear crank seal......
Title: Re: Unidentified oil leak
Post by: Jimbob on 07 February 2017, 16:39:46
I put my finger through the bung. Again seemed grimy not oily
Oil cooler bits all seemed fine
Title: Re: Unidentified oil leak
Post by: Migv6 le Frog Fan on 07 February 2017, 16:42:38
half moon at the rear of camcover sprung a leak ?  :-\
Title: Re: Unidentified oil leak
Post by: Jimbob on 07 February 2017, 17:09:26
Half moons were what I was hoping for. But nothing seems oily enough as far as I can see or reach

Covers aren't in the best shape. But not too bad either
Title: Re: Unidentified oil leak
Post by: Jimbob on 08 February 2017, 17:31:24
Had another good poke today before putting it back together.  Im convinced its not coming from the top.
I did find a coolant leak - the Aux coolant pump under the coolant tank is dripping.
I'd suggest oil filter area, managed a little nip of the oil cooler pipe and changed the oil filter and will see what happens overnight.
I think next is to degrease everything and monitor.
Title: Re: Unidentified oil leak
Post by: TheBoy on 08 February 2017, 17:55:22
I've been chasing similar on MV6.

Crank seals done, upper and lower sumps resealed without gaskets, cam covers done, just can't locate it.
Title: Re: Unidentified oil leak
Post by: Tick Tock on 08 February 2017, 20:18:28
Oil leaks on the V6 are part and parcel of the package, but with good maintenance can be made easier to live with.

The most obvious are cam cover seals, which are made worse by lack of cleaning of the breather system. Worst case scenario is rear crankshaft seal dripping, again possibly due to lack of maintenance. It's a major box-off jobbie to sort out.

Oil cooler failure can cause loss of oil into the cooling system - best not mention anymore about that.

Another location where engine oil can appear is the front lower area of the engine block. This can be either front crankshaft seal, or the oil pressure switch. I recently changed my cambelt, and the vee at the bottom was clean, but there is still a discernible trace of oil sitting on the front edge and dribbling down onto the plastic under engine cover. Maybe switch needs reseating.

Apart from that, can't think of any other susceptible areas.
Title: Re: Unidentified oil leak
Post by: TheBoy on 09 February 2017, 13:47:14
Apart from that, can't think of any other susceptible areas.
Oil pump. Looks an arse of a job.  I'm sort of suspecting thats where mine is. But I'll definately need a grown up to help me sort that one...
Title: Re: Unidentified oil leak
Post by: VXL V6 on 09 February 2017, 18:14:42
Apart from that, can't think of any other susceptible areas.
Oil pump. Looks an arse of a job.  I'm sort of suspecting thats where mine is. But I'll definately need a grown up to help me sort that one...
The other source of oil on the sump lip is from weeping cam seals (usually the exhaust cams) you'll not be able to spot this easily unless your changing the cambelt and remove the metal back plate.
Title: Re: Unidentified oil leak
Post by: TheBoy on 10 February 2017, 08:19:28
Apart from that, can't think of any other susceptible areas.
Oil pump. Looks an arse of a job.  I'm sort of suspecting thats where mine is. But I'll definately need a grown up to help me sort that one...
The other source of oil on the sump lip is from weeping cam seals (usually the exhaust cams) you'll not be able to spot this easily unless your changing the cambelt and remove the metal back plate.
In my case, Mr DTM has been in there more times than he probably cares to remember, seeing as HGs are service items on 1998 3.0l...
Title: Re: Unidentified oil leak
Post by: Jimbob on 26 February 2017, 14:33:10
Well a few days ago I gave the bottom a good scrub with gunk to make oil trails spottable,

Well the front crank seal is certainly weeping, but not enough to cause this, Nothing else at the front appears to be an issue, and oil certainly isnt being spread backwards.
Looking up at crank sensor and oil filter, nothing weeping around there at all, same looking up at the other side.

Only oil I can see, starts about half way up the bell housing seal on both sides, seeps into bellhousing, then mainly out of the inspection hatch before dripping off the bottom bolts.
Still leaves a small puddle every stop.

Title: Re: Unidentified oil leak
Post by: Doctor Gollum on 26 February 2017, 15:44:39
Rear crank seal :y
Title: Re: Unidentified oil leak
Post by: Jimbob on 26 February 2017, 16:31:36
Rear crank seal :y
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Rear crank seal :y

That's my fear.  :'( :'( :'(

Not quite sure what I can realistically do about that.
Title: Re: Unidentified oil leak
Post by: GastronomicKleptomaniac on 26 February 2017, 16:39:07
How much does serek charge to change rear crank srals? Its one job I dont fancy doing on jack and stands!
Title: Re: Unidentified oil leak
Post by: Jimbob on 26 February 2017, 16:58:13
How much does serek charge to change rear crank srals? Its one job I dont fancy doing on jack and stands!

Interesting thought. I'd do front and rear while at it
Title: Re: Unidentified oil leak
Post by: Doctor Gollum on 26 February 2017, 18:01:50
The seal is about £20, labour for dropping the box is circa £200.

From a preventative point of view, is there any mileage changing the oil pump when doing the front seal?
Title: Re: Unidentified oil leak
Post by: Nick W on 26 February 2017, 19:17:45
The seal is about £20, labour for dropping the box is circa £200.

From a preventative point of view, is there any mileage changing the oil pump when doing the front seal?


Only if the engine has low oil pressure. And that's likely to have much worse causes than a poor pump.
I just changed the seal when I did mine: an easy job once you've undone the crank bolt. Which is very tight!
Title: Re: Unidentified oil leak
Post by: Doctor Gollum on 26 February 2017, 22:28:13
Fair dos, wouldn't hurt to pull the pump and redo the block/pump seal whilst the pulley is off though :-\
Title: Re: Unidentified oil leak
Post by: Nick W on 26 February 2017, 23:12:44
Fair dos, wouldn't hurt to pull the pump and redo the block/pump seal whilst the pulley is off though :-\


I prefer not to tinker with stuff that's working. I find that means they last longer ;)
Title: Re: Unidentified oil leak
Post by: Marks DTM Calib on 27 February 2017, 08:22:14
Fair dos, wouldn't hurt to pull the pump and redo the block/pump seal whilst the pulley is off though :-\

Christ no, oil pump is a bitch of a job and involves removing aircon compressor ancillary brackets etc.
Title: Re: Unidentified oil leak
Post by: Pmacca2000 on 28 February 2017, 16:37:37
Sounds like the early stages of oil cooler failure to me.
Title: Re: Unidentified oil leak
Post by: Doctor Gollum on 28 February 2017, 16:41:20
Sounds like the early stages of oil cooler failure to me.
Utter rubbish. Sorry.
Title: Re: Unidentified oil leak
Post by: Migv6 le Frog Fan on 28 February 2017, 18:05:18
Sounds like the early stages of oil cooler failure to me.

Ive told you before and will tell you again. There is only one sign of oil cooler failure. That is - oil in the coolant.  ::)
Title: Re: Unidentified oil leak
Post by: dbug on 01 March 2017, 02:34:17
Sounds like the early stages of oil cooler failure to me.

As others have said, complete and utter crap.  I do wish members with little or no mechanical knowledge wouldn't post totally incorrect information/solutions to issues that may involve other members in unwarrented work/extra costs.  When a V6 oil cooler fails, you will see your coolant turn a murky brown - thats the correct and only visual sign of oil cooler failure.  The oil cooler sits in the middle of the "V", immersed in coolant - the only place for a blown oil cooler to leak is into the coolant, no where else.

Think your garage took advantage of you and your limited knowledge re oil cooler failure on your car - certainly think they ripped you off financially ::)  You will get better informed help/diagnostics on here, and certainly a more cost effective and correct diagnostics/repairs from some of the mobile mechs on here, or go to Serek's in Huntingdon for an honest, expert and cost effective repair service.
Title: Re: Unidentified oil leak
Post by: Marks DTM Calib on 01 March 2017, 10:45:43
It had a new oil cooler not so long ago as the block to cover plate seal was leaking coolant.
Title: Re: Unidentified oil leak
Post by: Jimbob on 01 March 2017, 12:02:39
looking in Tis, this is doable all from the back?  assumed the front needed locking the same as when doing the front seal?  guess that makes it easier to find someone competant to do it as no timing up needed afterwards.
Title: Re: Unidentified oil leak
Post by: Doctor Gollum on 01 March 2017, 12:14:11
looking in Tis, this is doable all from the back?  assumed the front needed locking the same as when doing the front seal?  guess that makes it easier to find someone competant to do it as no timing up needed afterwards.
Eh ???

Front seal is behind the crank pulley... Rear seal is, not surprisingly, at the rear of the engine requiring box out... be like changing the front number plate from the boot ::)

Leave the front one until the next belt change :y
Title: Re: Unidentified oil leak
Post by: Jimbob on 01 March 2017, 12:17:02
yes....thought the crank needed locking at the front with the 'big tool' to do either.....

therefore undoable by anyone you couldnt trust to time it up
Title: Re: Unidentified oil leak
Post by: Doctor Gollum on 01 March 2017, 12:29:21
yes....thought the crank needed locking at the front with the 'big tool' to do either.....

therefore undoable by anyone you couldnt trust to time it up
Crank doesn't need locking for the rear one ;)
Title: Re: Unidentified oil leak
Post by: Marks DTM Calib on 01 March 2017, 12:56:08
Its a flywheel or flex plate off job so 6 bolts (might be 8, cant recall) but no need to lock the crank like for the mega bolt on the NDE.

Still important not to rotate the crank the wrong way though.

Title: Re: Unidentified oil leak
Post by: Doctor Gollum on 01 March 2017, 13:11:29
I used a bell housing bolt and a suitably folded piece of plate to lock my flywheel ;) Guessing flex plate would be similar  :-\
Title: Re: Unidentified oil leak
Post by: TD on 01 March 2017, 17:52:09
I think the problem....its not oil at all, is melted rubber from the tyres, where you've been driving it too hard, leaking out of the tyre valves....4 new tyres and valves should sort it  :y ;D

Sorry, I couldn't help it  ::) :D