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Diff oil leak and smell

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Attilio
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Diff oil leak and smell

Post by Attilio » Thu Nov 30, 2017 9:42 pm

Hello there,

I recently purchased a Z4M and learned how tail happy it can be when roads are wet, cold and the tyres old and nearly bald :wink:

I had the car checked by an official bmw dealer before purchasing it and no issue was detected apart from the need to change the tyres and the brakes being half way towards replacement. The oil diff was replaced only few thousand miles ago.

This evening I had the car MoT’d (in fact NCT’d since I live in Ireland) and I was informed there Is a leak from the diff. I also noticed a hot oil smell when I parked the car... :o

I confess that I indulged in some long power slides; I know it’s not proper but couldn’t help it :roll:

It the leak a sign of serious trouble? Any advice, things I should be looking for?

Thanks in advance,
A
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srhutch
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Diff oil leak and smell

Post by srhutch » Thu Nov 30, 2017 9:56 pm

The diffs on these are known to weep. Be worth cleaning it up and keeping an eye on it.
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Diff oil leak and smell

Post by mr wilks » Thu Nov 30, 2017 10:04 pm

My last ZM ( at 8ok ) went from dry diff to weeping within a few thousand miles , new seals nothing major , mine was passenger side ( its a backbox off job ) £180ish total iirc ? i certainly wouldn't be doing many miles until its sorted :cry:
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Diff oil leak and smell

Post by srhutch » Thu Nov 30, 2017 10:09 pm

mr wilks wrote: Thu Nov 30, 2017 10:04 pm My last ZM ( at 8ok ) went from dry diff to weeping within a few thousand miles , new seals nothing major , mine was passenger side ( its a backbox off job ) £180ish total iirc ? i certainly wouldn't be doing many miles until its sorted :cry:
Yours was leaving oil on the drive from memory wasn’t it?
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Diff oil leak and smell

Post by mr wilks » Thu Nov 30, 2017 10:15 pm

srhutch wrote: Thu Nov 30, 2017 10:09 pm
mr wilks wrote: Thu Nov 30, 2017 10:04 pm My last ZM ( at 8ok ) went from dry diff to weeping within a few thousand miles , new seals nothing major , mine was passenger side ( its a backbox off job ) £180ish total iirc ? i certainly wouldn't be doing many miles until its sorted :cry:
Yours was leaving oil on the drive from memory wasn’t it?
Garage floor , zero oil drops from 9 months then parked up after a 300 mile weekend touring the Lake District passes ( for future reference i would never go over Hardknott Pass again in any car of my own ) next time it moved the oil drop was clear to see ( size of a 5p piece )
Spoke to my indy , didn't drive the car again until it was sorted as at that point there was no way of knowing what amount of oil was left in the diff .
The bill covered fresh oil , seal + labour
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Diff oil leak and smell

Post by srhutch » Thu Nov 30, 2017 10:20 pm

I might get a drip tray, just to remind me to check. It spends 300+ days a year in the garage so the best place to check it.
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Diff oil leak and smell

Post by Attilio » Thu Nov 30, 2017 11:27 pm

Thanks guys,

Will contact indipendent and main dealer to see who can fix it first; don’t want to take chances. Will keep you posted on the outcome. Wish me luck!

A
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Diff oil leak and smell

Post by bradz » Fri Dec 01, 2017 10:45 am

Agreed get it done, Once it starts it will get worse quickly- Well mine did anyway.

I went a bit OTT and took the diff out for a rebuild and all new seals :P
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Diff oil leak and smell

Post by Mangozac » Fri Dec 01, 2017 11:03 am

A knowledgeable BMW tech told me you want to get the diff seals done ASAP once you notice weeping. If the diff oil starts to sling around it gets onto the diff mounts it apparently causes the rubber to rot, meaning you would have to replace the mounts much sooner.
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Diff oil leak and smell

Post by srhutch » Fri Dec 01, 2017 2:24 pm

Mangozac wrote: Fri Dec 01, 2017 11:03 am A knowledgeable BMW tech told me you want to get the diff seals done ASAP once you notice weeping. If the diff oil starts to sling around it gets onto the diff mounts it apparently causes the rubber to rot, meaning you would have to replace the mounts much sooner.
Interesting as at the last England/Wales meet in April 15 there were a number of ///M's on the ramp from the forum at Dick Lovett where the dealer techs were looking over them. Nearl all if not all of them had weeping diffs/misting on the diff cases and the tech said it was common.
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Diff oil leak and smell

Post by Attilio » Fri Dec 01, 2017 4:53 pm

Thanks guys,

you scared me enough: leaving the office to go to BMW dealer to get an appointment... :cry:

will keep you posted; have a great weekend!
A
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Diff oil leak and smell

Post by Mangozac » Fri Dec 01, 2017 9:01 pm

srhutch wrote: Fri Dec 01, 2017 2:24 pm Interesting as at the last England/Wales meet in April 15 there were a number of ///M's on the ramp from the forum at Dick Lovett where the dealer techs were looking over them. Nearl all if not all of them had weeping diffs/misting on the diff cases and the tech said it was common.
Yes, it's extremely common on this diff. The weeping isn't the end of the world - he just knows I'm very particular about keeping my car mechanically tip top ;)
I wonder if there are improved seals available aftermarket?
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Diff oil leak and smell

Post by Beedub » Fri Dec 01, 2017 11:25 pm

bradz wrote: Fri Dec 01, 2017 10:45 am Agreed get it done, Once it starts it will get worse quickly- Well mine did anyway.

I went a bit OTT and took the diff out for a rebuild and all new seals :P


id do the same !! Over preventative FTW
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Diff oil leak and smell

Post by Attilio » Thu Dec 07, 2017 8:17 pm

All,

an update on the diff leak saga: my Z4MC is back at home with new seals on the differential (it was the one on the side of the prop shaft that was leaking very badly) and also with a new handbrake mechanism (yes, it was not working correctly and it had to be replaced).

I am a lot lighter having shed a pretty penny (loads in fact :o ) but the car is in really good shape now.

I nearly forgot: I also fitted two new Michelin Super Sports at the back (bloody hell they are really sticky compared to the old Contis!).

All good now :thumbsup: just have to find a way to earn more money! :wink:
Z4M Coupe, Interlagos blue, black leather, piano black, stubby, OEM CSLs, evolve intake, cup holders...pretty much stock
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