allroad 2.5 tdi quattro 2005 expansion tank

**quattrogary** · 11-06-2017,07:02 AM

Noticed some hairline cracks in my expansion tank

Seems a good idea to replace this. Having fun though finding a replacement.

Part is 4B0121403

No one seems to have this tank, is it a main dealer only ? I was supplied with the wrong tank from a site on ebay. Mine has one outlet at 180 degrees below and one outlet on the top

Thanks

**Doc B** · 15-06-2017,09:54 AM

Hi there

I had the same problem with my A6 Avant 2.5TDi recently. I bet you got a tank for a 4 cylinder car which only has 2 pipe connections & not the 3 that the V6 needs. I got a replacement from EuroCarParts for under £15 using their weekend discount. Normal price was around £22.

**Crasher** · 15-06-2017,10:10 AM

£20 for a ******* piece of crap off of fleaBay or £36.90 for a new one from Audi, noone makes and aftermarket version.

**quattrogary** · 15-06-2017,12:22 PM

Searched hi and low , it seems to be a main dealer part only

Picking one up from audi tomorrow for £36

Expect the tank would be fine, but not worth taking the risk

**Crasher** · 15-06-2017,01:21 PM

I put the number into Tec Doc and it said no, that is usually pretty conclusive and no further checking will help.

**Doc B** · 15-06-2017,02:01 PM

Originally Posted by Crasher

£20 for a ******* piece of crap off of fleaBay or £36.90 for a new one from Audi, noone makes and aftermarket version.

I didn't use fleabay but my (relatively) local ECP as my tank was leaking & I needed my car back on the road ASAP. Tank is made by Topran so I have no idea of quality relative to genuine part but I will keep an eye on it just in case. Apologies if I caused any offence by not buying a genuine part......

**Crasher** · 15-06-2017,05:43 PM

Doc, we overlapped as your post wasn't there when I opened the thread so it wasn't aimed at you.

**quattrogary** · 20-06-2017,08:44 AM

All fitted with new tank cap. G12 coolant refresh, looks good.

Cars nearley up together now where i would like it to be. Only issue left is a very slight rough start from cold for a second or two. I am sure its sucking in a tiny bit of air somewhere. Think i will wait until it gets colder to investigate.

New plugs / starter / battery has improved her a great deal along with a terraclean.

**03Allroad** · 26-06-2017,08:43 PM

Hey I notice you mention Terraclean - did it make any difference? I was thinking about getting my done as its not as good on fuel and power as I was expecting and wondered if this might sort it out?

**quattrogary** · 27-06-2017,03:15 PM

I removed the egr and had it remapped. For the same price i had the power taken to 217 bhp ( i dont drive it hard)

Also the garage i use carried out the terraclean the same time.

Runs very smoothly , also picks up very well. Seems to get through the gears quicker, could do with the a 6th gear !

Have not noticed improvement with mpg figures