Deisel Exhaust Fluid

I just bought a 09 X5 35d. After about 4000 miles my DEF light came on. I refilled T 500 miles to go with BMW 2 liter container. All was well for 300 miles. Now the indicator light is back on. Any ideas? How large is the is the tank?

Thks in advance.

Go to Autozone or the like and buy a two and a half gallo container of DEF. It should last about 5000 miles, unless you still have free maintenance than let the dealer fillet.

There are two tanks, combined they hold around 8 gallons.

I could tell you where they are at on the X5d but I'm not sure on the 335d.

Check out your owners manual.

Jay

Just edited. It is an 35D, not a 335d.

In that case, you have the active tank on the passenger side right behind the headlight, I'm sure that's the one you filled initially, its only holds ~2 gallons.

The passive tank (large resevoir that is not heated and only acts as a reserve tank) is filled by removing the fresh air intake that runs on the drivers side of the engine bay. It picks up the air right in front of the radiator and carries it back to the air filter box that is on the back side of the engine cover. The plastic intake has tabs that need to be depressed to pop it loose on both ends, once you have that removed you'll see a similar refill port as the active tank that is easily seen. This tank holds ~6 gallons so will take a good deal more fluid.

As mentioned, stop by a truck stop, auto parts store, or farm & fleet and get yourself a couple 2 1/2 gallon jugs of the stuff, just make sure you take your take filling as you need to let air escape while filling or else it will burp and make a mess. I also like to dump a bucket of water on the area after I refill and recap, and then wipe it down with a paper towel or shop rag. The DEF isn't corrosive to stainless or plastic, but it is semi-corrosive to aluminum.

If you need pictures, I can send you a diesel training manual that I have for the 35d and the 335d that was posted a while ago on here. Just PM me your e-mail address, its a good read for all diesel owners.

Jay

Jay

thks

Check your pm.

I filled it myself and just didn't have the right fittings, so needed to jimmy up some tubing. Next chance I get I'll snoop around at the dealer and get the right size bottle to use as a funnel or something.

Yeah, its free while under the maintenance agreement, but I didn't want to bother, and don't know if its covered "between" service visits. I love to tinker around my cars.

PL

Originally Posted by Pierre Louis

I filled it myself and just didn't have the right fittings, so needed to jimmy up some tubing. Next chance I get I'll snoop around at the dealer and get the right size bottle to use as a funnel or something.

Yeah, its free while under the maintenance agreement, but I didn't want to bother, and don't know if its covered "between" service visits. I love to tinker around my cars.

PL

Many have converted the one time use 1/2 gallon bottle as a filler. It already has the correct fitting. The fitting will come off, just unscrew hard (the plastic will crack but still works). You can refill the 1/2 gallon or drill a hole in it to put the hose from the 2.5 gallon jug having the 1/2 act as a transfer container.

Originally Posted by KeithS

Many have converted the one time use 1/2 gallon bottle as a filler. It already has the correct fitting. The fitting will come off, just unscrew hard (the plastic will crack but still works). You can refill the 1/2 gallon or drill a hole in it to put the hose from the 2.5 gallon jug having the 1/2 act as a transfer container.

Yeah, I was planning to do this. Which fitting plastic cracked on you? Mine are covered with plastic caps that seem pretty robust, but plastic. At first they looked like they needed a special tool to get off, with an insertable large bit, but they both just screwed off nicely. Not Mercedes quality, but OK so far.

PL

The bottle I got (from VW, $9) had locking tabs so the main valve/cap would not come off (easily). Some people carefully cut away the locking tabs. I just forced the cap off and it cracked at the lip that engaged the tabs. Still 100% usable.

Originally Posted by KeithS

The bottle I got (from VW, $9) had locking tabs so the main valve/cap would not come off (easily). Some people carefully cut away the locking tabs. I just forced the cap off and it cracked at the lip that engaged the tabs. Still 100% usable.

I'd just do the bottle mod, photos to follow:


Cheers
D.

p.s. 2 gal bottle of DEF shouldn't be much more than $10-12.


1/2 gal bottle



Cap collar before cutting tabs



Some tabs cut to get the top off the bottle



Cap off, before trimming off all the locking tabs



All the tabs trimmed off to allow cap to be removed and replaced repeatedly



Cap trimmed and back on the 1/2 gal bottle - refill as required when the DEF No-start warning illuminates.

So I just filled the small tank and because the message indicator had come on, assumed that the big tank was also empty. However, it did not take any fluid as it was full.

Does that mean the pump from the big tank is not working?

Suggestions?

Thks in advance.

How cold has it gotten? I have read that it is possible for the fluid in the big tank to freeze, and then the active tank can be depleted. Is is possible that this has happened on your car?

OTOH, there have also been reports about the pump failing on the passive tank, so you might be on the right track. Just trying to give you ideas!

See attached. There are several possible reasons why passive tank is full and active tank is empty. As you'll read, sometimes the pump is not actually faulty but needs to be primed. This is beyond my DIY capabilities. Could also be that DEF is frozen. This happened to me once.

Originally Posted by Thomv

So I just filled the small tank and because the message indicator had come on, assumed that the big tank was also empty. However, it did not take any fluid as it was full.

Does that mean the pump from the big tank is not working?

Suggestions?

Thks in advance.

Thomv, do you mean you tried adding fluid to the upper filler, and that you couldn't get any fluid in at all?

The only reasonably possible way I could se that happening is if the tank is completely full (assuming it isn't frozen solid). Not impossible, but that would take a failed transfer pump (passive to active) to cause that.

Cheers
D.

Originally Posted by Thomv

So I just filled the small tank and because the message indicator had come on, assumed that the big tank was also empty. However, it did not take any fluid as it was full.

Does that mean the pump from the big tank is not working?

Suggestions?

Thks in advance.

When I went in for service I got a software update that they claimed fixed an issue where the passive tank wasn't getting pumped to the active tank.

Sent from my DROIDX using Bimmer App

Vehicle is in a heated garage and temps have not gotten below 25.

After filling the active tank, I checked the passive tank and it was full.

If you have an OBDII reader, you might be able to check for a failed transfer pump, it'll show up as code 0046-EB. If that isn't failed, then it could be a cracked interconnect line, but I'm pretty sure that would also allow the passive tank to drain, and you noted it was full (just wondering, by the way, how you confirmed that the passive tank was filled? Wouldn't fill more? [using the upper filler tube in the DEF filler compartment])

Cheers
D

Does anyone have the proper procedure for filling the DEF tanks?
Last month I filled up the Active tank (lower filler) but also had difficulty filling up the Passive tank (upper filler).
I wonder do we have to open both filler caps before starting the fill up?

My D was due for an oil change and refill of the DEF so I assume the DEF tanks were almost empty since the iDrive warning was on.
But I could only get in maybe slightly more than 3 gallons and it wouldn't fill any more.

Originally Posted by DC-IT

I wonder do we have to open both filler caps before starting the fill up?

But I could only get in maybe slightly more than 3 gallons and it wouldn't fill any more.

It should not be necessary to open both filler caps to fill the passive tank. They are not connected, except through the transfer line.

As for quantities, I believe in an E90 the passive tank is 14.4l (3.8 US gallons) and the active tank is 7.4l (1.95 US gallons). Not sure if you mean 3 gallons in total or 3 gallons in passive tank. If you put 3 gallons in passive tank you are good to go. If not , it is possible your transfer pump is not working or filter is clogged or something like that.

I believe (not positive) iDrive warning can be triggered by either tank, as they both have sensors, but passive tank sensor only reads "empty" or "full" whereas active tank level sensor reads "full", "warning", and "empty". Actually, this can't be exactly right because if passive tank is empty and active tank is full you still have quite a bit of DEF left.

Do you just use the lower filler to do the refill or do you also have to pour the DEF into the upper filler?

I believed I've poured in 3~4 Gals.
It's been five weeks since the refill and so far so good.

My ML's AdBlue tank has only one filler so it makes it so easy to refill the DEF and it's in the trunk where you insert the refill bottle directly above the tank filler and push it downwards to release the DEF.
That is so easy to do.

The 335d's refillers are awkwardly placed and not as easy to refill.

The Passat TDI also has an easy access to the refiller.

I'll see how far I can travel before the DEF refill warning shows up.

I need a bit of clarification after looking pictures and videos.

The filler on the passenger side of he vehicle is the passive tank and the filler under the air intake is the active tank or am I backwards? (my wife claims this is the case most of the time)

I able to put fluid in the one on the passenger side. The other one never takes any fluid.

As always, thks in advance.

Thom

Originally Posted by DC-IT

Do you just use the lower filler to do the refill or do you also have to pour the DEF into the upper filler?

I believed I've poured in 3~4 Gals.

DC-IT, we have gone off-topic as OP is asking about X5. In any event, in an E90, lower filler is for active tank, upper filler is for passive tank. Total capacity is about 5.75 US gallons. Since your tanks were not empty and you put in 3-4 gallons, you should be good for quite a while.

I did the same thing. You need the small refill container so you have the' right nozel fitting. They dont sell the nozel anywhere that i can tell.

I bought a new 2010. I have 85K miles on it and every concievable maintenance issue you can imagine. I love the car but you could be in for a costly maintenance issue when you get the miles up. I had a cylinder replacement done because of diesel fuel carbon build up. I am not a car tech person but it di cost $16k by the time it was all finished. BMW took care of most of the expense- thank god.