Oily mess... Is this a tandem pump seal failure?

Fishman

Fishman

A2OC Donor
IMG_20210409_144634.jpgIMG_20210409_144617.jpg

A2 has failed its MOT on an oil leak. I've tracked it down to coming from the top right of the back of the engine. It's a bit cramped around there but I'm curious of this looks like a tandem pump seal failure.
 
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Fishman said:
What for the Bosch pump?
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yes the Bosch pump it to large for the BHC/ATL engines without a spacer to move the ASV towards the passenger side

I've just packaged up your check strap so last chance for the drain screw to go 'carriage free' It going to the drop off shop in 5 mins so let me know straight away if you want the drain screw

Cheers,
Paul
 
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depronman said:
yes the Bosch pump it to large for the BHC/ATL engines without a spacer to move the ASV towards the passenger side

I've just packaged up your check strap so last chance for the drain screw to go 'carriage free' It going to the drop off shop in 5 mins so let me know straight away if you want the drain screw

Cheers,
Paul
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Please check your DM's
 
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Linked to @philward's comment there - as an FYI ; the Polo dog bone looks different at the gearbox end, but the important chassis subframe end where the bushing is that deteriorates is identical. For that you save at least 20 quid on Audi prices for the required part. All you need to do is swap the gearbox end piece of folded steel for your existing one - just takes a socket set or spanner with a decent length lever on it to get the bolt undone and job's a good 'un.
 
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Before you start trying to get a replacement rocker gasket, thoroughly clean the area first. After cleaning I would remove the rocker to inspect the gasket and relevant part numbers and see what is reusable, may even be a leak due to incorrect torquing of the bolts.
Do the tandem pump which will need a good clean in the area anyway. replace any rubber hoses as needed and follow the slick down to see if the bog bone has gone. Pressure wash the undertray being careful not to cause damage to the insulation blocks. With the back of the engine now clean and the rocker cover gasket checked and torqued. The EGR replaced use the car and check back for new leaks that will be very easy to find.
 
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The insulation blocks on the under tray are toast. I can only assume hot oil falling on it has made the egg crate bit on the undertray collapse.

I have a Polo style dogbone ready to fit. I believe the main culprit for all this oil IS the rocker cover. The tandem pump and EGR are also playing a part but the rate of the flow is significant with the engine running.
 
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audifan said:
Here is the parts diagram for the rocker cover and gasket...

cylinder head; cylinder head cover Audi A2 (A2) 2005 year Audi EUROPA 103042

cylinder head<br/>cylinder head cover Audi A2 (A2) 2005 year Audi EUROPA 103042 spare parts
audi.7zap.com audi.7zap.com

If you look to the right of the part number under applicability you see it is used on other cars, and if you look further right a list of aftermarket suppliers and their part numbers comes up.
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The only problem is that most links unfortunately lead you to the gasket, not the cover. I've been through this repeatedly recently - I did manage to get a new rocker cover from Deutsche Parts in the run up to Christmas which was about the last one.

Couple of comments from my mechanics regarding these and leaks. There is a specific order in the garage manual with sequence and torques for bolting them down and conversely unbolting them - apparently similar on a 1.9tdi of the same era. Failure to do it this way in either case resulted in the lid warping and never tightening down properly again with concomitant leaks, even with a new seal, liquid gasket cream and a good clean up beforehand, and with older cars it is quite possible that the lid has been warped on your behalf by previous owners or mechanics.
 
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As far as parts listing shows the same part number rocker cover across the entire diesel range and used on other vehicles.

The manual gives full disassembly and assembly instructions including the order as pointed out by @Robin_Cox . Crucially it also states exactly where to apply extra sealant along with other important notes.

Manual page below...

Audi Workshop Service and Repair Manuals > A2 > Power unit | 3-cylinder TDI unit injector engine (1.4 ltr. 2-valve), mechanics | Engine cylinder head, valve gear | Cylinder head | Removing and installing cylinder head cover

A2 > Audi Workshop Service and Repair Manuals > Power unit | 3-cylinder TDI unit injector engine (1.4 ltr. 2-valve), mechanics | Engine cylinder head, valve gear | Cylinder head | Removing and installing cylinder head cover
workshop-manuals.com
 
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So what did I find today...

The rocker cover was leaking like there's no tomorrow because the firstly the seal had no silicone sealant applied in accordance with the workshop manual but more worrying was that the rear bolts on the rocker cover were loose... Not even finger tight!

Whilst I was there I have removed the EGR (awaiting a delivery from depronman) and also slackened the tandem pump (awaiting a new Bosch pump and seal).

Underneath the car I removed the track rod ends and ARB drop-links.
 
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Provided it is undamaged and the rocker is pretty flat then thorough cleaning and the application of the sealant where required ( the step normally missed out ) and the bolts torqued in the order specified in the manual is sufficient. Easier to do the rocker with the EGR out the way. What are you doing with the EGR? Reemeber to completely clean all old oil / diesel from the engine and surrounding areas. Before you disconnect the fuel lines from the tandem protect the entire area against diesel spill as it will rot rubber pipes VERY quickly and is not good for the rubber seals in the electrical plugs.
 
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audifan said:
Provided it is undamaged and the rocker is pretty flat then thorough cleaning and the application of the sealant where required ( the step normally missed out ) and the bolts torqued in the order specified in the manual is sufficient. Easier to do the rocker with the EGR out the way. What are you doing with the EGR? Reemeber to completely clean all old oil / diesel from the engine and surrounding areas. Before you disconnect the fuel lines from the tandem protect the entire area against diesel spill as it will rot rubber pipes VERY quickly and is not good for the rubber seals in the electrical plugs.
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The old EGR is a bit leaky too, depronman is supplying one of his modified units with the ASV retained but the EGR internal components all removed.
The tandem pump lines will be removed when the rocker cover and EGR is back in situ. I just cracked the mounting bolts on it as today I was trying to get all of the jobs started as I'm waiting for a lot of new parts!
 
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Thats great. As far as the EGR is concerned there are 2 schools of thought. The after 20-30000 miles they do nothing so may as well machine it out but keep the externals to fool the testers. Then there is the school of thought that they do reduce emissions so when faulty / old replace them. Remember to blank off the vacuum actuating pipe to the tandem.
Did you source a Bosch tandem at a good price and get a good gasket also?

Personally I replaced the EGR.
 
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audifan said:
Thats great. As far as the EGR is concerned there are 2 schools of thought. The after 20-30000 miles they do nothing so may as well machine it out but keep the externals to fool the testers. Then there is the school of thought that they do reduce emissions so when faulty / old replace them. Remember to blank off the vacuum actuating pipe to the tandem.
Did you source a Bosch tandem at a good price and get a good gasket also?

Personally I replaced the EGR.
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£174 for the tandem pump and the proper gasket was £8
 
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