please help identifying what im missing here

chris55552 · 11-12-2023, 04:01 PM

So i noticed some oily leakage around my manual transmission today and pulled the shields off to discover a small peep hole like door or cover on the bottom of my transmisssion and cant figure out what im missing here. It cant be good though. Thanks in advance for taking the time to look and help.

Phil325i · 11-13-2023, 03:52 AM

Fairly sure that hole is meant to be there. Enables you to view the starter ring and flywheel. Might be normally covered by a grommet, but it doesn't explain your oil leak. I would suggest your crankshaft main rear seal is weeping. Just had mine done for that reason after 140,000 miles. Hope that helps.

PhaceN52 · 11-13-2023, 04:35 AM

Oil pan gasket or rear main seal, as Phil said that hole is meant to be there

chris55552 · 11-18-2023, 09:37 AM

how expensive is that to fix? Thanks for the input by the way..

PhaceN52 · 11-19-2023, 05:35 AM

You are willing to diy or prefer to take the car to an indy shop? For the oil pan gasket you'd spend likely 50$ dollars in parts and a day of your time, having it repaired at an indy you're looking north of 5/600$ I think. The rear main is a bit more involved since you have to separate the transmission, remove the flywheel, use a special tool to insert the seal while using a special loctite product, and it can become one of those labors where you'll find yourself doing other things just because "you're in there", like clutch related components... big difference

Efthreeoh · 11-22-2023, 03:58 PM

Quote:

Originally Posted by PhaceN52

You are willing to diy or prefer to take the car to an indy shop? For the oil pan gasket you'd spend likely 50$ dollars in parts and a day of your time, having it repaired at an indy you're looking north of 5/600$ I think. The rear main is a bit more involved since you have to separate the transmission, remove the flywheel, use a special tool to insert the seal while using a special loctite product, and it can become one of those labors where you'll find yourself doing other things just because "you're in there", like clutch related components... big difference

Most professional mechanics do not replace the rear crank seal if it is not leaking during a clutch job. The reason is, there is a 50/50 chance of the new seal leaking, which means rework for them. When I did my clutch at 300,000 miles, the rear crank seal was not leaking, so i left it alone. It's still not leaking at 422,000.

OP that hole is just a manufacturing alignment hole for the engine block. Nothing goes in it, there are no missing parts.

PhaceN52 · 11-22-2023, 07:13 PM

Quote:

Originally Posted by Efthreeoh

Most professional mechanics do not replace the rear crank seal if it is not leaking during a clutch job. The reason is, there is a 50/50 chance of the new seal leaking, which means rework for them. When I did my clutch at 300,000 miles, the rear crank seal was not leaking, so i left it alone. It's still not leaking at 422,000.

OP that hole is just a manufacturing alignment hole for the engine block. Nothing goes in it, there are no missing parts.

Yeah you're totally right about not touching the main seals, "if it's not broken don't fix it"

was just an hypothesis assuming his' was leaking...
Glad to hear yours is still good after all the miles you've put on, gives hope to someone who fears all is going to break (me)

I'm just at 210000km (130k miles) but every time it redlines feels like it's new and indestructible... Very well engineered imho

CLEAN13BOOSTED · 11-22-2023, 08:23 PM

Agree, looks like engine oil, rear main/oil pan. If you can monitor the leak until it's time for a clutch you'll save a bunch on labor!

Efthreeoh · 11-23-2023, 07:32 AM

In 2016 I posted a N52 clutch replacement DIY, where I mentioned the following (pics included).

When I pulled the transmission to replace the clutch, I found a lot of oil clinging to the inside of the bell housing. At that time (293,000 miles) the oil pan gasket had been visibly seeping for about 100,000 miles. It was leaking (rather than seeping) at the back of the engine block, which is not visible via inspection. The clutch pressure plate has fins built into the case that induce airflow in the bell housing to cool the clutch. The air flow pulls oil impregnated air from the lower engine block where the oil runs down from the leaking OPG and sprays it over the inside of the bell housing. The oil then runs down to the bottom of the bell housing where the oil drips from the clutch inspection opening, which makes it look like the rear crank seal may be leaking.

Most likely this is the case with the OP's car.

11-12-2023, 04:01 PM	#1
chris55552 Private 37 Rep 90 Posts Drives: 2017 BMW x3 35i Join Date: Jul 2023 Location: alexandra LA iTrader: (0)	please help identifying what im missing here So i noticed some oily leakage around my manual transmission today and pulled the shields off to discover a small peep hole like door or cover on the bottom of my transmisssion and cant figure out what im missing here. It cant be good though. Thanks in advance for taking the time to look and help. Attached Images
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11-13-2023, 03:52 AM	#2
Phil325i Brigadier General 616 Rep 3,194 Posts Drives: E92 325i MSport Coupe Join Date: Apr 2012 Location: UK South East iTrader: (1) Garage List 2009 BMW 325i Coupe [6.00]	Fairly sure that hole is meant to be there. Enables you to view the starter ring and flywheel. Might be normally covered by a grommet, but it doesn't explain your oil leak. I would suggest your crankshaft main rear seal is weeping. Just had mine done for that reason after 140,000 miles. Hope that helps. __________________ E92 pre-LCI 325i - Ohlins R&T; H&R spacers; M3 strut brace; Swift thrust sheets; 3 x chassis braces; diff brace; N53 V-brace; 034 subframe inserts; BMS clutch stop; BMS CDV; RE g/box mounts; Delrin shift bushes; Saikoumichi OCC; Cyba scoops; BMW Perf Exhaust; HEL s/steel brake hoses; M3 rear spoiler; Recaro Sportster CSs; M3 white dash LEDs; LED Angels; LED side repeaters; BMW Perf black grille; CSL reps; SSDD carbon diffuser; Monster Wrap black roof/clear front
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11-13-2023, 04:35 AM	#3
PhaceN52 Private First Class 175 Rep 189 Posts Drives: '06 E90 N52B30 US spec Join Date: Mar 2016 Location: Italy, Dolomites iTrader: (0)	Oil pan gasket or rear main seal, as Phil said that hole is meant to be there
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11-18-2023, 09:37 AM	#4
chris55552 Private 37 Rep 90 Posts Drives: 2017 BMW x3 35i Join Date: Jul 2023 Location: alexandra LA iTrader: (0)	how expensive is that to fix? Thanks for the input by the way..
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11-19-2023, 05:35 AM	#5
PhaceN52 Private First Class 175 Rep 189 Posts Drives: '06 E90 N52B30 US spec Join Date: Mar 2016 Location: Italy, Dolomites iTrader: (0)	You are willing to diy or prefer to take the car to an indy shop? For the oil pan gasket you'd spend likely 50$ dollars in parts and a day of your time, having it repaired at an indy you're looking north of 5/600$ I think. The rear main is a bit more involved since you have to separate the transmission, remove the flywheel, use a special tool to insert the seal while using a special loctite product, and it can become one of those labors where you'll find yourself doing other things just because "you're in there", like clutch related components... big difference
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11-22-2023, 08:23 PM	#8
CLEAN13BOOSTED Private First Class 74 Rep 104 Posts Drives: 2013 BMW E93 3351 Join Date: Oct 2023 Location: FLORIDA iTrader: (0)	Agree, looks like engine oil, rear main/oil pan. If you can monitor the leak until it's time for a clutch you'll save a bunch on labor!
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11-23-2023, 07:32 AM	#9
Efthreeoh General 17317 Rep 18,740 Posts Drives: The E90 + Z4 Coupe & Z3 R'ster Join Date: May 2012 Location: Virginia iTrader: (0)	In 2016 I posted a N52 clutch replacement DIY, where I mentioned the following (pics included). When I pulled the transmission to replace the clutch, I found a lot of oil clinging to the inside of the bell housing. At that time (293,000 miles) the oil pan gasket had been visibly seeping for about 100,000 miles. It was leaking (rather than seeping) at the back of the engine block, which is not visible via inspection. The clutch pressure plate has fins built into the case that induce airflow in the bell housing to cool the clutch. The air flow pulls oil impregnated air from the lower engine block where the oil runs down from the leaking OPG and sprays it over the inside of the bell housing. The oil then runs down to the bottom of the bell housing where the oil drips from the clutch inspection opening, which makes it look like the rear crank seal may be leaking. Most likely this is the case with the OP's car. __________________ A manual transmission can be set to "comfort", "sport", and "track" modes simply by the technique and speed at which you shift it; it doesn't need "modes", modes are for manumatics that try to behave like a real 3-pedal manual transmission. If you can money-shift it, it's a manual transmission. "Yeah, but NO ONE puts an automatic trans shift knob on a manual transmission."
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