Bad Oil Leak, Can't locate... - Driving me MAD!!

[Almurray42]

Hi All

I'm going to try and be as descriptive as possible here, but the short story is that I have a BAD oil leak on my 09' A3 8P (CBAB Engine code), back of engine and need help locating where It could be coming from!

Long Story:

So, I obtained the car with an issue of low oil pressure. After Taking the Sump off, I discovered that the oil pump Hex drive key was excessively worn and as such was slipping in the shaft. New key - Problem solved.

After fresh oil & filter, I started noticing a strong burning smell of oil. I took the undertray off and ran it for a while to find a consistent Drip, drip of oil from the back of the engine - Drivers side (Cambelt end).

I've tried tracing where the drip is coming from and have discovered the "Trail" so far..

Image 1 is an Image from the Web of a Reconditioned CBAB engine for reference to help show where my images relate to.

IMAGE 1

At first sight, I spotted the oil dripping from the lower bracket of the engine mount, and traced this up the engine. Image 2 shows in RED where the oil is coming from, and Green where there is no trace of oil. (This is an image of a used engine from ebay)

IMAGE 2

 

Image 3 shows the Oil leak as high as I can see where it starts to Pool, and drip/run down the block. Yellow Circles show where the Oil appears to be coming from. The Blue line is where oil is sitting along the Head gasket, but I believe that this is where it's running down to, as the source of the oil is pooling on the Rear Cambelt Cover Bolt.

 

Image 4 is the same as Image 1, but cropped.  Yellow circle shows where I'm seeing the oil "Pooling" around the rear cam cover bolt.

The only places that I can think that the oil COULD be coming from is:

Camshaft Oil seal or Front Cam Blanking Plug (GREEN) - However I'd have thought I'd see oil flicking around the cambelt or on the cam sprocket, which I don't

Camshaft Carrier to Head (PINK) - This is a Sealing surface that clamps the CAMS into the head.. There doesn't appear to be oil running down from here, but hard to tell as the oil "trail" seems to disappear above the bolt.

Rocker(Cam) cover gasket (BLUE) - I have had the Rocker cover off, cleaned the sealing surface and replaced the rocket cover gasket - no joy whatsoever. The Rocker cover is currently OFF again so I could check again!

IMAGE 4

 

SOO.. This is driving me mad, I really want to get this back on the road but need to get this sorted. Has anyone experienced a similar leak? I'm reluctant to go taking the Cambelt off if unnecessary, as then I'd have to get a new belt & Tensioner, and will need to buy all the locking tools etc. - Obviously if I HAVE TO, then I will. My question is, is there something that i've missed that could be the cause? I've already taken off the Camshaft position sensor and it's not coming from there.

Any help/advice would be GREATLY appreciated. I'm half tempted to get a new Rocker cover, as these are the plastic ones that can apparently warp and understand that potentially if the PCV has failed then it could be causing higher pressure in the engine thus forcing the oil out from somewhere? 

I Very much look forward to hearing opinions or advice!

Kind Regards;

Al

 

[Stevey Y]

On 5/30/2023 at 11:20 AM, Almurray42 said:

Hi All

I'm going to try and be as descriptive as possible here, but the short story is that I have a BAD oil leak on my 09' A3 8P (CBAB Engine code), back of engine and need help locating where It could be coming from!

Long Story:

So, I obtained the car with an issue of low oil pressure. After Taking the Sump off, I discovered that the oil pump Hex drive key was excessively worn and as such was slipping in the shaft. New key - Problem solved.

After fresh oil & filter, I started noticing a strong burning smell of oil. I took the undertray off and ran it for a while to find a consistent Drip, drip of oil from the back of the engine - Drivers side (Cambelt end).

I've tried tracing where the drip is coming from and have discovered the "Trail" so far..

Image 1 is an Image from the Web of a Reconditioned CBAB engine for reference to help show where my images relate to.

IMAGE 1

At first sight, I spotted the oil dripping from the lower bracket of the engine mount, and traced this up the engine. Image 2 shows in RED where the oil is coming from, and Green where there is no trace of oil. (This is an image of a used engine from ebay)

IMAGE 2

 

Image 3 shows the Oil leak as high as I can see where it starts to Pool, and drip/run down the block. Yellow Circles show where the Oil appears to be coming from. The Blue line is where oil is sitting along the Head gasket, but I believe that this is where it's running down to, as the source of the oil is pooling on the Rear Cambelt Cover Bolt.

 

Image 4 is the same as Image 1, but cropped.  Yellow circle shows where I'm seeing the oil "Pooling" around the rear cam cover bolt.

The only places that I can think that the oil COULD be coming from is:

Camshaft Oil seal or Front Cam Blanking Plug (GREEN) - However I'd have thought I'd see oil flicking around the cambelt or on the cam sprocket, which I don't

Camshaft Carrier to Head (PINK) - This is a Sealing surface that clamps the CAMS into the head.. There doesn't appear to be oil running down from here, but hard to tell as the oil "trail" seems to disappear above the bolt.

Rocker(Cam) cover gasket (BLUE) - I have had the Rocker cover off, cleaned the sealing surface and replaced the rocket cover gasket - no joy whatsoever. The Rocker cover is currently OFF again so I could check again!

IMAGE 4

 

SOO.. This is driving me mad, I really want to get this back on the road but need to get this sorted. Has anyone experienced a similar leak? I'm reluctant to go taking the Cambelt off if unnecessary, as then I'd have to get a new belt & Tensioner, and will need to buy all the locking tools etc. - Obviously if I HAVE TO, then I will. My question is, is there something that i've missed that could be the cause? I've already taken off the Camshaft position sensor and it's not coming from there.

Any help/advice would be GREATLY appreciated. I'm half tempted to get a new Rocker cover, as these are the plastic ones that can apparently warp and understand that potentially if the PCV has failed then it could be causing higher pressure in the engine thus forcing the oil out from somewhere? 

I Very much look forward to hearing opinions or advice!

Kind Regards;

Al

 

Hi an educated guess would be either the crankshaft oil seal or the camshaft seal, you will have to have the cam belt off to replace the seals, you might as well do both whilst there that should nail it and a new belt kit wouldn't be out of town, do you know when it was last changed.

Steve.

[Almurray42]

11 minutes ago, Stevey Y said:

Hi an educated guess would be either the crankshaft oil seal or the camshaft seal, you will have to have the cam belt off to replace the seals, you might as well do both whilst there that should nail it and a new belt kit wouldn't be out of town, do you know when it was last changed.

Steve.

Thanks Steve

I don't think it's coming from the Crankshaft seal as this is much lower than where i'm seeing the oil dripping from - I've decided that my best course of action is to do the Camshaft oil Seal. I've started taking things off in preparation, just waiting for my Locking kit to arrive. Cambelt Was last changed at 85K and now at 115K, so only 30K on it but think while I have it off, it's worth doing.

I'll update here Hopefully tomorrow provided Amazon deliver my locking kit before dark! Having the Rear timing belt cover off will definitely give me visibility as to where it's actually coming from.

Al 

[Stevey Y]

7 minutes ago, Almurray42 said:

Thanks Steve

I don't think it's coming from the Crankshaft seal as this is much lower than where i'm seeing the oil dripping from - I've decided that my best course of action is to do the Camshaft oil Seal. I've started taking things off in preparation, just waiting for my Locking kit to arrive. Cambelt Was last changed at 85K and now at 115K, so only 30K on it but think while I have it off, it's worth doing.

I'll update here Hopefully tomorrow provided Amazon deliver my locking kit before dark! Having the Rear timing belt cover off will definitely give me visibility as to where it's actually coming from.

Al 

Hi Al I wish you luck ad a speedy solution, oil on a cam belt is pretty deadly and toxic as oil and rubber don't get on ask any Transit owner about the wet belt, yes its a rubber belt that is immersed in oil, and Fords have replaced a shed load of engines under warranty and they still don't get it, its a rubbish idea, problem is oil has a capillary action and flies everywhere especially when being propelled by something thats going at speed.

Steve. 

[Almurray42]

22 hours ago, Stevey Y said:

Hi Al I wish you luck ad a speedy solution, oil on a cam belt is pretty deadly and toxic as oil and rubber don't get on ask any Transit owner about the wet belt, yes its a rubber belt that is immersed in oil, and Fords have replaced a shed load of engines under warranty and they still don't get it, its a rubbish idea, problem is oil has a capillary action and flies everywhere especially when being propelled by something thats going at speed.

Steve. 

Well.. I appear to have found the cause of the leak.

Camshaft oil seal... Until I looked deeper..

Took off the Cambelt and Camshaft sprocket -To see a nice oily drip from the Camshaft seal. Image below:

 

I looked on the inside after spotting this, and noticed that the where the exhaust cam exits the Head, there looked to be excessive rubbing/wear on one side and a gap on the other (the green is UV dye from when I was tracing).. Image below:

 

So I decided to take the Camshaft retaining frame off to have a better look and ohhhh dear... See images:

 

 

 

Interestingly, There aren't Bushes/Bearing shells to replace as i'd have thought there would be... The Cams just run directly in the seats of the Head & Cam carrier... Is this even fixable?

😞

Al

[Stevey Y]

4 hours ago, Almurray42 said:

Well.. I appear to have found the cause of the leak.

Camshaft oil seal... Until I looked deeper..

Took off the Cambelt and Camshaft sprocket -To see a nice oily drip from the Camshaft seal. Image below:

 

I looked on the inside after spotting this, and noticed that the where the exhaust cam exits the Head, there looked to be excessive rubbing/wear on one side and a gap on the other (the green is UV dye from when I was tracing).. Image below:

 

So I decided to take the Camshaft retaining frame off to have a better look and ohhhh dear... See images:

 

 

 

Interestingly, There aren't Bushes/Bearing shells to replace as i'd have thought there would be... The Cams just run directly in the seats of the Head & Cam carrier... Is this even fixable?

😞

Al

Hi Al that is a disaster in so much as the oil pressure issues have done for the head the cam seal is leaking from the movement in the camshaft, all that scoring is from intermittent loss of oil pressure which has caused the two components to meet and rub on each other causing the scoring, there are no bearings as most modern engines run interference fit bearings and rely on a oil pressure wedge to keep the cam and bearing surfaces apart, either way you will need a new cylinder head/camshaft and depending on the milage one would have to consider the expense of that in view of the fact that the big end bearings are probably the same.

Steve.

[Almurray42]

Update:

Big End Bearing Caps Off, Bearings look very good, but will replace while i'm at it.

Cylinder head off - Cylinder Bores look good. 

Plan of action:

New (Used) Cylinder head

Head Gasket

Exhaust & Inlet manifold Gaskets

Clean EGR valve

Cam belt & Tensioner

New Big End bearings + Stretch Bolts

Piston Rings & Hone Cylinders

 

Anything else I should do while stripped down this far?

[cliffcoggin]

Do the water pump while the engine is stripped if you have not done so already.

[Stevey Y]

On 6/12/2023 at 1:00 PM, Almurray42 said:

Update:

Big End Bearing Caps Off, Bearings look very good, but will replace while i'm at it.

Cylinder head off - Cylinder Bores look good. 

Plan of action:

New (Used) Cylinder head

Head Gasket

Exhaust & Inlet manifold Gaskets

Clean EGR valve

Cam belt & Tensioner

New Big End bearings + Stretch Bolts

Piston Rings & Hone Cylinders

 

Anything else I should do while stripped down this far?

Hi Al if the big ends look okay you are in with a shout, if you can get a reasonable cylinder head used that what I would go for and just re cut the valve seats lap them in and with all the rest you are doing you should get a perfectly serviceable engine, I would also suggest a new oil pump.

[Almurray42]

1 hour ago, cliffcoggin said:

Do the water pump while the engine is stripped if you have not done so already.

Hi Cliff

I was thinking about this - water pump was last done at 70k and it's at 115k now... Reckon it needs doing?

[Almurray42]

1 hour ago, Stevey Y said:

Hi Al if the big ends look okay you are in with a shout, if you can get a reasonable cylinder head used that what I would go for and just re cut the valve seats lap them in and with all the rest you are doing you should get a perfectly serviceable engine, I would also suggest a new oil pump.

Thanks Steve

Replacement head arrived today, from an engine on 85k and it's in remarkably good nick! 

Are the valve seats and relapping strictly necessary would you say? I don't really want to have to disassemble the head and take it to a shop to get the seats cut... Wouldn't that also mean new valves for fresh seats? Then if I'm doing valves may as well do valve stem seals, lifters and rocker arms... Its a bit of a rabbit hole 😂

Al

[Stevey Y]

17 hours ago, Almurray42 said:

Thanks Steve

Replacement head arrived today, from an engine on 85k and it's in remarkably good nick! 

Are the valve seats and relapping strictly necessary would you say? I don't really want to have to disassemble the head and take it to a shop to get the seats cut... Wouldn't that also mean new valves for fresh seats? Then if I'm doing valves may as well do valve stem seals, lifters and rocker arms... Its a bit of a rabbit hole 😂

Al

Hi Al it all boils down to the ship and the halfpenny of tar, it just makes a better job of the head even if you get the seats cut and lapped in theres not normally any need to buy new rocker gear or valves unless the existing valves are pitted, this will ensure that with the hone and rings it runs like new.

Steve. 

[cliffcoggin]

On 6/14/2023 at 9:01 PM, Almurray42 said:

Hi Cliff

I was thinking about this - water pump was last done at 70k and it's at 115k now... Reckon it needs doing?

No it should not need doing now, but it will do in another 30000 miles. If you plan to keep the car that long then it will save you another strip down if you do it now.

[Almurray42]

Update: Parts on way from Germany.

I am Doing the 100mm Balance Shaft Mod to avoid this from happening again as this was all the result of the SH1t3 Engineering on the Oil pump hex drive keyway in the Balance Shaft. 

For anyone else reading, after a LOT of research it seems that unless you want to spend £150+ on a replacement/exchange balance shaft part, the only available option is the Kit from ZED engineering here - https://shop.zedperformance.co.uk/passat-a4-2.0-tdi-balance-shaft ?search=balance shaft

This kit comes with a SS threaded "Bolt" insert with a 6mm Hex shaft and a longer, 100mm Hex key. 

This is what I'll be doing. I've got a chap I know that works in a machine shop and he will drill & Tap the shaft and put in the insert for me. The problem that this creates is that there's nothing in the Audi Workshop manuals or it seems anywhere about disassembling and reassembling the balance shaft...

I loosened off the bolts in a diagonal out-in sequence. 

For the 2 halves of the balance shaft assembly there are:

QTY 9: M8 x 50mm (1.25mm Thread Pitch) Grade 8.8 Bolts (Unserrated Flange Bolts)

QTY 3: M8 x 30mm (1.25mnm Thread Pitch) Grade 8.8 Bolts (Unserrated Flange Bolts)

Unfortunately as Audi only sell the complete balance shaft unit,  they don't list part numbers for replacement bolts or torque settings. I'm assuming that being Grade 8.8 they are also stretch bolts and as such need replacing.

The closest VAG part numbers i've found for replacements of these bolts are:

QTY 9: N91063901

QTY 3: N10665001

I have ordered some of these for reassembly. Need to figure out appropriate torque settings... I'm assuming it'll be similar to the torque settings needed for attaching the Balance shaft assembly to the block. Happy to share photos and final results when reassembling if it'd help anyone...

The saga continues... 

 

Al

[Almurray42]

On 6/16/2023 at 6:44 PM, cliffcoggin said:

No it should not need doing now, but it will do in another 30000 miles. If you plan to keep the car that long then it will save you another strip down if you do it now.

I've taken a step back and agree with your Logic. Ordered a Full kit now with Tensioners, Idler rollers, Timing belt and water pump (INA so should be good quality!)

[Almurray42]

Update for anyone else looking at the Balance shaft mod to 100mm with improved shaft... Kit arrived from ZED performance, and Using a combination of Common sense and similar torque ratings with same size/grade bolts on the car, I'll be using the below Torque settings for The two halves of the balance shaft:

1 - Hand Tighten 

2- Diagonally Outwards from Centre: 8nm

3 - Same pattern, 20nm

4 - Additional 90 Degrees.

Note: If anyone plans to re-use the old bolts, I'd recommend NOT doing step 4 and instead adding a decent high-temp threadlock to the threads.

Building my knowledge as I go, but want to share as I do so... There doesn't seem to be a wealth of info out there relating to this mod even though the issue seems quite common!

Al

[Almurray42]

Final Update!

So, I've completed all the work (Finally!) and the car is back together and running! No Oil leak! 😄

In the end, I did:

Replacement Cylinder Head (Stripped, cleaned, cleaned and soaked Rocker arms & lifters)

Head Gasket (+Plenty of other gaskets & Seals!)

Camshaft Oil seal

Piston Rings (& Cylinder Hone)

Big end bearings (& Big end cap bolts)

Intake manifold & EGR teardown & Clean

Balance Shaft Mod for 100mm Keyway

Oil pump check/clean/soak

Timing belt (Including water pump, Tensioner, all pulleys, idlers, studs & bolts)

Aux Belt

------

Note: When refitting the balance shaft assembly, you're supposed to use a locking tool that's around £40, which I couldn't justify for  minutes use, so I took some measurements and made a locking tool from Acrylic on my Laser cutter, Happy to share pics of this if anyone's interested.. Could even sell them for a small amount if anyone needs one!

-----

Thanks for following along, MOT up next! 😮

Al

[alpha omega]

doing this type of work is beyond me i take my hat off to you.well done glad theres no oil leaks after all that work😎

[cliffcoggin]

Congratulations. That's a substantial amount of work and expense on a fourteen year old car.

[Steve Q]

Great amount of work, well done.

[Almurray42]

Thanks All, it was quite an undertaking considering I'm An electronics engineer - the polar opposite of a mechanic! Ultimately, it started as an oil leak fix and gradually spiralled to almost a full rebuild! 

 

All in though, I've learned a lot and very pleased with the results, thanks again for the advice here and there people! 

 

Al

[Stevey Y]

58 minutes ago, Almurray42 said:

Thanks All, it was quite an undertaking considering I'm An electronics engineer - the polar opposite of a mechanic! Ultimately, it started as an oil leak fix and gradually spiralled to almost a full rebuild! 

 

All in though, I've learned a lot and very pleased with the results, thanks again for the advice here and there people! 

 

Al

Hi Al great result having got the bit between your teeth you have succeeded a lesson for  us all, just shows you the disciplines of your electrical knowledge can be applied to mechanical issues and save you money doing it yourself, well done.

Steve.