rs4 b7 expansion tank and cap

[rs user]

hi folks has anybody got a link or part number for coolant expansion tank/cap-noticed mine has a few small cracks in it nearest engine
would like to replace it as a precaution

[iduff]

https://www.ecstuning.com/ES436248/

OEM part number according to ECS is 8E0121403F for the tank.

https://www.ecstuning.com/Audi-B7_RS4-- ... /ES253082/

OEM part number according to ECS is 3B0121321 for the cap.

My tank just cracked, and I replaced it. I was able to do so without losing any coolant by doing the rapid shuffle of hoses once I unplugged them from the old tank, and by dumping the coolant in the old tank into the new tank once it was all plumbed and plugged in. Don't forget to plug in the level sensor on the bottom o the tank.

[MikeFish]

Expansion tank is about £17 from Audi, dont pay more to buy it from ebay etc.
For the cap, why not splash out and get an R8 one?

[rs user]

thanks folks...r8 cap=does it work better lol

[marc1]

Makes it quicker Arthur.

I've just bought a new tank from the local dealer. It was £22. The last one I bought was about £16 from Stoke Audi. I couldn't be bothered trying to source it cheaper so paid the £22.

[PetrolDave]

Makes it quicker Arthur.

+1

The Audi part number is 420 121 321.

BTW the R8 oil filler cap (420 103 485 B) is also a direct fit.

[rs user]

using the numbers above i ordered pattern kit off ebay £24 for tank/cap delivered

the fancy r8 caps look good i suppose but bling aint my thing ... well not for caps but i like a bit of carbon...

[Harris.]

Ordered mine from Southend Audi , arrives Friday £22

[marc1]

using the numbers above i ordered pattern kit off ebay £24 for tank/cap delivered

the fancy r8 caps look good i suppose but bling aint my thing ... well not for caps but i like a bit of carbon...

Good job. There will be plenty of it in your inlet manifold.

[rs user]

using the numbers above i ordered pattern kit off ebay £24 for tank/cap delivered

the fancy r8 caps look good i suppose but bling aint my thing ... well not for caps but i like a bit of carbon...

Good job. There will be plenty of it in your inlet manifold.

[docurley]

Just did mine today after I noticed u this





bought tank from eurocarpart for £18

[MikeFish]

That Vaico label would annoy me though. Buy from Stoke Audi for the same price.

[MB2]

Now it is in maybe nail polish remover on the Vaico logo ?

[rs user]

mine is now fitted too-5 minute job
would urge anybody who has a b7 to inspect their expansion tank properly,mine was original,lots of deep cracks in several areas 10 years old/99k
none of these cars are young and most which have original tanks will exhibit this-they do generate a fair bit of heat for a n/a car-probably something to do with a huge engine shoehorned into a medium saloon car lol

[Daytona]

What he said^
I came across the same thing whilst moving the tank to change the upper arms.
Do Audi check anything whist servicing? Probably too busy valeting it or plumping the cushions in the waiting room.