Help from My Delete Brothers

Marin_Oil_Burner · 01-20-2023, 12:24 AM

He Y'all,

I have about 125k on my 335d Msport and have run into the dreaded DEF tank/pump issues. I have the 4804 and 474C codes. I've re-filled the DEF tank and the codes went away, but came back about a week later. It's been raining a lot here so I couldn't tell if I had a leak in the DEF tank, but the other day it was dry and I noticed when I drove away from the curb, there was a streak of liquid on the road. I managed to capture this pic. I think it is roughly where the active tank is located. The liquid was dripping off the shield. The liquid was slippery, but I didn't notice an ammonia smell, so i think it was DEF.

In any case, I'm having my shop do a smoke test to see if it was one of the lines, but if it was the tank and there was a crack, I'm a bit screwed. Here is the ask....if anyone has an active tank in good shape left over from a delete, I'd be interested. Please DM me.

Of course some will say, why don't I delete....I'm in CA, so a bit stuck. Thanks in advance!

lnxguy · 01-20-2023, 09:57 AM

North American BMW Owners group on Facebook. Someone will probably give you one for free.

Marin_Oil_Burner · 01-20-2023, 12:22 PM

Yeah, good suggestion I'll post there. thanks!

POBEP · 01-23-2023, 03:05 AM

Marin_Oil_Burner - unlikely for the tank to leak.

The 4804 code is a clear sign of DEF pump struggling to maintain line pressure (which has nothing to do with tank integrity)
What is likely to fail is a nipple on the delivery module (DEF pump).
It first start to leak like yours, then within short amount of time/mileage fails completely and spills DEF like crazy.
The nipple is not repairable - you'll need replacement pump.

I just finished pump replacement for my E90 - nearly identical symptoms.

You still will need to remove bumper/exhaust and entire DEF tank to clean up mess, verify issue and, likely, replace the pump

Overall simple DIY, just a lot of steps.
The hardest part is to get bumper unclipped.
Everything else is super easy.
I did it all on 4 jack stands without any special tools.

I got used pump from a member in this forum.
Another option is a new Bosch unit from FCP.

Also, I recommend verifying DEF Mixer placement in the front exhaust section.
It is unrelated to the issue you seeing, but has 50:50 chance that is it not installed correctly.
Mine was placed in reverse by "genius" certified technicians of BMW San Rafael who replaced DEF tank under warranty, but failed to replaced pump.
I also suspect that DEF pump nipple was damaged due to improper re-assembly.

Strictlybusiness335 · 02-24-2023, 06:24 PM

I'd have to agree with it being either the nipple or the metering line connection at the nipple. With that being said, the nipple is repairable here's a link for a replacement.

https://xemodex.com/us/product/bmw-d...t-replacement/

I also wouldn't drop the exhaust or any of that, I'd go in through the trunk it's MUCH simpler and gives you direct access to the pump, nipple, lines etc etc. It's like 10 10mm nuts and then you have to grind/cut out out center of the 2 circle mounts on the trunk plate and it will pop right up. When you're all done tap and thread holes into those mounts so you can bolt it together the plate helps hold up the tank.

nonford · 02-25-2023, 09:48 AM

Mine was leaking like that and it was a bad o-ring on the pump. Yea, you dont need to drop the exhaust completely. Remove the trunk cover plate, it'll all stare you in the face and easy access.

BB_cuda · 02-26-2023, 09:27 PM

A couple entries above confused me.
The access panel can be removed without grinding/cutting anything to see top of tanks, pumps, etc.

MidWillamette335d · 02-27-2023, 09:31 AM

Quote:

Originally Posted by BB_cuda

A couple entries above confused me.

lol, you're not the only one. I think just dropping the exhaust (6 bolts I think, 2 on each sleeve, 1 on each hanger...), then the heat shield (to access the nuts that are holding the tank up....the same nuts that are attached the welded studs on the panel) would be a much wiser move, and probably less time consuming all said and done. I think you'll end up hating yourself if you went another route. That being said, if someone has successfully done the grind method post up some pics of the end result!

POBEP · 02-27-2023, 10:59 AM

Quote:

Originally Posted by MidWillamette335d

lol, you're not the only one. I think just dropping the exhaust (6 bolts I think, 2 on each sleeve, 1 on each hanger...), then the heat shield (to access the nuts that are holding the tank up....the same nuts that are attached the welded studs on the panel) would be a much wiser move, and probably less time consuming all said and done. I think you'll end up hating yourself if you went another route. That being said, if someone has successfully done the grind method post up some pics of the end result!

I agree with MidWillamette335d - exhaust drop, even full removal "sounds" like a big job, but it is not. In fact, it is quite simple and fast.

Exhaust drop and complete tank removal provides an opportunity to wash DEF tank (and guts) outside and flush internals with distilled water.

Having said above, DEF tank removal needs rear bumper to come out.
There are lots of screws to unfasten, but not rocket science either

01-20-2023, 12:24 AM	#1
Marin_Oil_Burner Enlisted Member 7 Rep 36 Posts Drives: LeMans Blue 335d M-sport Join Date: May 2015 Location: San Rafael, CA iTrader: (0)	Help from My Delete Brothers - DEF Tank Needed..Probably He Y'all, I have about 125k on my 335d Msport and have run into the dreaded DEF tank/pump issues. I have the 4804 and 474C codes. I've re-filled the DEF tank and the codes went away, but came back about a week later. It's been raining a lot here so I couldn't tell if I had a leak in the DEF tank, but the other day it was dry and I noticed when I drove away from the curb, there was a streak of liquid on the road. I managed to capture this pic. I think it is roughly where the active tank is located. The liquid was dripping off the shield. The liquid was slippery, but I didn't notice an ammonia smell, so i think it was DEF. In any case, I'm having my shop do a smoke test to see if it was one of the lines, but if it was the tank and there was a crack, I'm a bit screwed. Here is the ask....if anyone has an active tank in good shape left over from a delete, I'd be interested. Please DM me. Of course some will say, why don't I delete....I'm in CA, so a bit stuck. Thanks in advance! Attached Images
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01-20-2023, 09:57 AM	#2
lnxguy Lieutenant Colonel 357 Rep 1,723 Posts Drives: 2009 335D Join Date: Jun 2016 Location: Barrie iTrader: (1)	North American BMW Owners group on Facebook. Someone will probably give you one for free. __________________ '09 335D
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01-20-2023, 12:22 PM	#3
Marin_Oil_Burner Enlisted Member 7 Rep 36 Posts Drives: LeMans Blue 335d M-sport Join Date: May 2015 Location: San Rafael, CA iTrader: (0)	Yeah, good suggestion I'll post there. thanks!
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01-23-2023, 03:05 AM	#4
POBEP Lieutenant 364 Rep 552 Posts Drives: E70 E90 E91 Join Date: Mar 2016 Location: Christmas Valley, CA iTrader: (0) Garage List 2011 E90 335d [9.33] 2013 E70 xDrive35d [5.00] 2009 E91 328i [10.00] 2016 F25 xDrive28d [0.00]	Marin_Oil_Burner - unlikely for the tank to leak. The 4804 code is a clear sign of DEF pump struggling to maintain line pressure (which has nothing to do with tank integrity) What is likely to fail is a nipple on the delivery module (DEF pump). It first start to leak like yours, then within short amount of time/mileage fails completely and spills DEF like crazy. The nipple is not repairable - you'll need replacement pump. I just finished pump replacement for my E90 - nearly identical symptoms. You still will need to remove bumper/exhaust and entire DEF tank to clean up mess, verify issue and, likely, replace the pump Overall simple DIY, just a lot of steps. The hardest part is to get bumper unclipped. Everything else is super easy. I did it all on 4 jack stands without any special tools. I got used pump from a member in this forum. Another option is a new Bosch unit from FCP. Also, I recommend verifying DEF Mixer placement in the front exhaust section. It is unrelated to the issue you seeing, but has 50:50 chance that is it not installed correctly. Mine was placed in reverse by "genius" certified technicians of BMW San Rafael who replaced DEF tank under warranty, but failed to replaced pump. I also suspect that DEF pump nipple was damaged due to improper re-assembly. __________________ Last edited by POBEP; 01-23-2023 at 03:39 AM..
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02-24-2023, 06:24 PM	#5
Strictlybusiness335 New Member 2 Rep 13 Posts Drives: 335d Join Date: Feb 2023 Location: SoCal/HD/IE iTrader: (0)	I'd have to agree with it being either the nipple or the metering line connection at the nipple. With that being said, the nipple is repairable here's a link for a replacement. https://xemodex.com/us/product/bmw-d...t-replacement/ I also wouldn't drop the exhaust or any of that, I'd go in through the trunk it's MUCH simpler and gives you direct access to the pump, nipple, lines etc etc. It's like 10 10mm nuts and then you have to grind/cut out out center of the 2 circle mounts on the trunk plate and it will pop right up. When you're all done tap and thread holes into those mounts so you can bolt it together the plate helps hold up the tank.
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02-25-2023, 09:48 AM	#6
nonford Private First Class 8 Rep 103 Posts Drives: 2011 335d, 2019 X3 Join Date: Jun 2009 Location: New Mexico iTrader: (4)	Mine was leaking like that and it was a bad o-ring on the pump. Yea, you dont need to drop the exhaust completely. Remove the trunk cover plate, it'll all stare you in the face and easy access.
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02-26-2023, 09:27 PM	#7
BB_cuda Brigadier General 765 Rep 3,556 Posts Drives: 2011 335D Msport, 2013 X5D Join Date: Nov 2011 Location: Clear Lake, Texas iTrader: (0)	A couple entries above confused me. The access panel can be removed without grinding/cutting anything to see top of tanks, pumps, etc.
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