# Leaking DEF Heater Unit



## cabaniss (Dec 27, 2014)

I wanted to post a question to the group to see if anyone has experienced leaks around the top of the DEF heater.

My 2014 Cruze triggered the 35% DEF warning, so I decided to add some fluid.

While filling, I noticed some crystals down in the well of the trunk.
Apparently it had been leaking for some time as it was a mess with several clumps the size of a ping pong ball.
I wish I had thought about taking pictures before I cleaned it up.

Luckily it is easy to clean by disconnecting connectors / hoses and removing the tank and crystals dissolve quickly in water and can be wiped out.
I suspect this is corrosive as it is a Urea mixture, so I want to keep it from happening again.

I am still trying to find the source of the leak, it appears to be around a grommet where 2 wires emerge from the unit.
The grommet is integral to the tank, so this might be a job for some RTV sealant.

I had to replace the DEF heater at 45,000 miles as it was faulty. The original one did not leak.

If anyone has experienced this, I would like to hear from you.


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## MP81 (Jul 20, 2015)

Are you sure it is leaking and someone didn't just spill a bunch trying to fill it?


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## sailurman (Sep 29, 2016)

Did you replace it yourself, or have it replaced? Is this the first time you have looked at it since the replacement?


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## CruzeDan (May 17, 2015)

It seems strange that it would leak there, as the tank is not under pressure.


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## cabaniss (Dec 27, 2014)

Thanks to all who responded.

I am confident that no DEF has been spilled during filling as I always do this myself and take care to be sure to wipe up any drops.

Yes, I did replace this myself, but was careful to make sure no O-rings or seals were crimped or damaged. I do plan to remove the pump to check its seal this weekend.

You are correct that the tank is not under pressure, I have the covers removed and it seems to spit a drop or two out of the top grommet during turns. I suspect due to fluid sloshing around. 

A simple but nuisance problem. I hope to find the leak this weekend. I will post what I find.


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## Diesel Dan (May 18, 2013)

Well at least you get a low level warning! 
Mine shows 15lb on the scan gauge when it ran empty and after adding 2.5 gallons. Need to take it in some day.


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## SkuurBruuh (Mar 13, 2018)

My heater unit was replaced last summer as well and I have the exactly same thing as you. A leak from the same are as you. When I realized, the bottom of the trunk was filled with DEF to a point where it got into the car and started crystallize on the seatbelt buckles. It's at the dealer now, because it may be covered by them. 2014 cruze diesel here also.


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## SkuurBruuh (Mar 13, 2018)

So the dealer called me, the car is ready. It's a grommet tuat was leaking. Thwy did it under warranty (car has 52k miles). The heater unit is covered till 120k miles (and the grommet too since when you change the heater you change the grommets and other parts also) so if you encounter this problem, just go to the dealer.


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## sailurman (Sep 29, 2016)

Crap. Now I have to inspect :disgust (1)::disgust (1):


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## cabaniss (Dec 27, 2014)

I appreciate the comments from the group.
My problem was identical to the posting by SkuurBruuh.

After spending about an hour searching for a leak around the exiting wires on the DEF heater, I removed the pump and compared it against the old unit that I luckily saved when I replaced it. I noticed that the replacement unit was missing one of the 2 buna seals (thick o-ring). I moved the one from the previous unit. It appears this was missing and I did not notice it during the install. It was leaking around the pump and quickly flowing to other areas, making the origin point hard to pinpoint. 

Problem solved, thanks for the support of the forum.


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