Replacing oil sump pan, anything special to consider?

[furfurfur]

Last year I had a garage perform an oil change on my 3.0 TDI, as I was too busy at the time to DIY which I usually do. (never again)

About 500 miles after that I got a low oil level warning and needed to top up a litre or so. And so it continued for 10 months until now. The loss wasn't bad enough to make me panic but I knew something wasn't quite right.

So after preparing for an oil change at the weekend I could see that oil was quite clearly coming from the sump plug and it was a BUGGER to undo, so I reckon the monkeys had re-used the crush washer and over-torqued the plug, causing my issue.

Replaced the washer and plug today with a new magnetic jobby, and the bugger is still leaking my brand new oil. I've drained and reclaimed the oil, so now it seems I have a problem with the thread or a crack near the plug which I can't see clearly crawling around under the car.

So I'm thinking the next step is replacing the oil pan as it looks like I can get a s/h one for about £60 off eBay so that hardly breaks the bank. I will see how much Audi want for a new one though.

The only thing which is worrying me is the risk is any of the 30 or so hex bolts being seized - it only takes one to ruin your day, however they look in 'OK' condition and I did crack one or two to check and they turned fine.

Before I proceed down this route, any warnings or words of advice?

[niall campbell]

I would put on a brand new one and gasket

I would also buy the 30 hex bolts as well

I have nightmares about replacing sumps as for some reason I find they all leak !!!!!!!!!!

The plug is metal going into aluminium and strips dead easy

[furfurfur]

Right, I'll get Mr. Audi to price that up for me tomorrow. There's no gasket though as far as I can tell, it's the silicone sealant which I may need some advice on too :)

[dan2485]

The sump is sealed with a sump sealer not silicone.

[furfurfur]

The parts catalog calls it out as “silicon sealant” with part number D 176501A1 and after googling that I see Loctite 5970 as the equivalent, does that sound right?

[niall campbell]

you could try TPS ........... Trade Part Specialist as well for a price, same parts usually

I find though they are the same price as VAG for a lot of things

If you got to Audi parts Dept in person, they might actually tell you the torque settings for the hex bolts, or pop into the workshop to ask........................... all for free

I try & save as much money as I can, but for the sump, I would get the real McCoy in sealant

You could get a spare sump plug ........................................... or even try a new sump plug for the leak ?

[smaugc6]

I had to replace the sump on my 2.7 tdi recently, it was I believe 120£ from audi, from experience many of the second hand sumps off eBay have rust or damage to the protective paint which causes leaks further down the line. Although my sump was totally caved in thanks to some debry that flew off the back of a HGV on the M5

[furfurfur]

Thanks all for the replies. I've ordered a new sump pan from Audi at £130. Am sourcing new bolts myself - they are M6x25 grade 8.8 hex bolts and I need about 35 of them. Also en-route is the official sealant and new seal for the oil level / temp sensor.

[furfurfur]

Happy to report success on this. All of the 33 bolts came off easily even though many looked quite rusted. Surprised that so many bolts were needed since the pan was quite hard to remove anyway with all the sealant keeping it stuck on there. Needed a lot of force to pull it off. I'd have been worried around damaging the pan had the plan been to re-fit the same one.

Once off it was simple enough to transfer the oil level/temp sensor to the new pan, using a new seal and the original bolts.

I then used a small knife to clean the upper sump pan mating surface as best I could. The hardest part was cleaning the old sealant out of the 33 bolt holes. Wasn't sure if I really needed to do that, but thought better safe than sorry.

2mm bead of sealant on the new pan, and positioned it in place and bolted up within a few minutes. Torque for new bolts are 5Nm plus 90 degree turn in a diagonal fashion. Filled with oil, no evidence of any leaks after leaving overnight, or after the first up-to-temperature drive. Confident enough to put the undertray back now.

[niall campbell]

excellent