[Yozh]

I had decided to yank my urea tank out with all it's ancillary components such as transfer pump, filter, brackets, nuts, bolts, heat shield, etc.

The capacity for the passive tank is 14.4 litres and for the active 7.4, together 21.8 litres. Assuming it is full it will weigh 21.8 kg or 48 lbs. The tank itself with all it's bells and whistles is 9 kg or 19.85 lbs and a bit. There are a few brackets that I think I will remove next time, so should help a bit.

In conclusion, if your urea tank is completely full, you are hauling about 70lbs of dead weight behind you.

Now, I would not suggest anyone pulling the tank just to save 20lbs. My hope (and a few others' on this forum) is I will be able to repurpose the space for a spare.

More pics to come with a few ideas on how to clean/fix the tank if problematic.

[Yozh]

Here is a mess that I had starter with. I swear, there was a pound of dirt on this thing.

[Yozh]

With the dust off, there is this huge urea mountain. It all came out over time from a vent that is right beside the delivery module. I must note that I had never had an error code for the urea for the time that I had owned it at least.

[Yozh]

Here it is all cleaned up. And the vent highlighted.





I had removed the delivery module. Was very easy, just remove three screws and a few electrical connectors. Then a look inside. All clean after I flushed it with water.

Attachment 1207229

Attachment 1207230

is this only for north american models or all ?

[Yozh]

From briefly playing around with this, I feel that one can easily do some maintenance on the urea tank if some problems are identified and may potentially point to some crystallization. Crystallized urea is very easy to clean-up with warm water. Tank will not need to be removed for that either. If any of the electronic components need to be replaced, that can fairly easy be replaced as well. From the look at realOEM, each component has a part number and should be able to be ordered separately. Looking at all of this, I'm surprised that dealers were replacing the whole thing. Not too difficult to do, but I suppose this is all from the lack of experience diagnosing problems related to SCR components. I think going down the road, folks that fear their warranty running out and being afraid of the SCR system, I would not.

[Mik325tds]

Thanks for posting this, Yozh. Was the removal straight forward after removing the exhaust?

[GreekboyD]

Sweet Yozh. Great door stop.

[Kjelly]

Originally Posted by Yozh

From briefly playing around with this, I feel that one can easily do some maintenance on the urea tank if some problems are identified and may potentially point to some crystallization. Crystallized urea is very easy to clean-up with warm water. Tank will not need to be removed for that either. If any of the electronic components need to be replaced, that can fairly easy be replaced as well. From the look at realOEM, each component has a part number and should be able to be ordered separately. Looking at all of this, I'm surprised that dealers were replacing the whole thing. Not too difficult to do, but I suppose this is all from the lack of experience diagnosing problems related to SCR components. I think going down the road, folks that fear their warranty running out and being afraid of the SCR system, I would not.

How would one clean that crystallized area (the vent area) without removing the tank? Do your pictures show the bottom side of the tank?

[Puerto Rican 335d]

Bravo Zulu

[joe_planet]

By the amount of dirt and crap on your tank I assume its mounted under the car. Where is its approximate location?

[rulonger]

Originally Posted by joe_planet

By the amount of dirt and crap on your tank I assume its mounted under the car. Where is its approximate location?

Under the trunk (boot).

[BB_cuda]

The dirty area is on the upper side of the tank. It is this weird gray dust. The tank is down below the trunk structure hanging from the black plate I showed in the other thread. First picture shows black rubber donuts where black plate bolts go through.

Great job yozh! You finally got the lift time to do this job. I've held off on this job per his warning of 1) doing it on a lift and 2) having a helper to deal with the long exhaust system. Exhaust has to be dropped to removed both the large corrugated cover and more importantly the large passive tank.

Can you possibly take a picture of the empty area below the black plate? Perhaps it's too late if he reattached the large corrugated cover. Here is link to my earlier thread to compare dust pictures. http://www.e90post.com/forums/showth...3#post17070863

[Yozh]

Originally Posted by Mik325tds

Thanks for posting this, Yozh. Was the removal straight forward after removing the exhaust?

Yeah the exhaust is challenging simply because it is so heavy. A second person is a welcome addition. I have used a tranny jack and a small ladder to help, plus a buddy just for lowering and raising back up.

Originally Posted by Kjelly

How would one clean that crystallized area (the vent area) without removing the tank? Do your pictures show the bottom side of the tank?

The delivery unit with the rest of the connections on the top is a bit tricky to access. One would think that you can just unscrew the subfloor in the trunk and see the top of the urea tank. Not. The tank is hanging off the subfloor panel. I believe someone else had suggested a way, sorry I do not remember who.

If you want to access the top of the idea tank to fix or replace anything. Then one would definitely need to drop the exhaust, remove the heat shields and then support the urea tank from the bottom, unscrew it from the subfloor and then you can lift off the subfloor by unscrewing it from the trunk, plus a small little pesky bracket from the bottom. Or you can just lower the urea tank a bit to work on it, whatever one finds easier. Also, that urea accumulation is weird, it is from a vent, but seems quite a bit. Doubt it has caused any issues though, I had no codes.

Here are a few more pictures of the tank and associated hardware.

[rulonger]

Yozh - Does this removal create enough space to retrofit a spare tire well in the trunk? If it does create enough space for that, I am interested. I am tired of my trunk space being consumed by the spare tire.

[Yozh]

That is the idea, to stick a spare under there. The challenge is to clear the exhaust. Of course, the dead weight of mufflers has to come off. I do not know if it would be able to be retrieved from the top. Next time the car will be on a lift I shall do more planning.

[BB_cuda]

Dumb question. The corrugated covers had to be left off too, right? Nothing to secure them to.
For those that haven't dug into this area yet, see the several grayish studs sticking out from both tanks? The corrugated covers have holes that slip over these and then washers with integral nuts fasten the covers down. 10 mm socket removes the washer/nuts but they are only a hair past hand tight.

[TDIwyse]

Originally Posted by Yozh

I had decided to yank my urea tank out ...

Thanks for this post Yozh. As another data point, the urea crystallization buildup on mine did not appear to be as bad as yours. This was with ~3 years and ~40k miles of use before it "stopped working" and urea had been drained and tanks flushed with distilled water.

[Yozh]

Did you remove yours as well then?

Also, one thing that I think is worth mentioning. I was pleasantly surprised that there were no codes with this delete. Thank you, you know who, for such fine DDE tuning and thank you Mark, you also know who, to remind me of this marvel.

[TDIwyse]

Originally Posted by Yozh

Did you remove yours as well then?

Also, one thing that I think is worth mentioning. I was pleasantly surprised that there were no codes with this delete. Thank you, you know who, for such fine DDE tuning and thank you Mark, you also know who, to remind me of this marvel.

Yes, yanked it all out. Your weights were very similar to what I measured.

Interestingly enough I still had a fair bit of distilled water left in the tanks. I had used the drain lines for the active and passive tanks to drain previously, and let things drain until no fluid came out, but it evidently doesn't completely drain the tanks...

Also, not having any issues with codes, so that's confirmation of your experience and Jarek's modification capability.

BB_Cuda, you had asked about leaving off the rear heat shields due to the tanks having some of the mounting tabs. I left those off. The redneck rear diffuser I fashioned over a year ago covers up that whole section anyway, so from the underside, visually my car looks the same as it did previous to this removal.

[Puerto Rican 335d]

This is my urea tank a couple of years ago when it went bad on me

[Yozh]

Just for the record. My urea tank has never given me a problem, even with that mess pictured.