tuffcalc

Drove about 2km and then back home today (forgot something). I left the car idling and ran inside to grab missing item. When I jumped back in the truck I noticed the exhaust had a very, very strong smell of ammonia.

It was about 2C outside. What's interesting is all this talk about the Bluetec class action I've been reading that states the Bluetec DEF system is shutoff below 10C. Judging from the strong ammonia smell my GLK250 was definitely dosing DEF into the exhaust while it was idling - in cold(ish) weather to boot.

A few things - has anyone ever noticed this smell, and has Mercedes actually confirmed at what temperature the Bluetec emissions controls are shut off (the smell today seems to fly in the face of all the talk about emissions control shutoff below 10C).

super7pilot

I have had that smell a few times. Terrible smell but It's normal. Not sure about the temp cutoff. But I thought that was why MB has a heating element in the DEF tank. Perhaps it's a bit different for our friends in the great white north.

The likely reason you got the assault on your nose was the short stop and go drive. At speed the system rarely kicks in. I mostly do highway miles, And in the 37,000 miles i have driven the 250. I have filled the DEF tank 3-4 times.

107123210

The US case has been thrown out, at least temporarily:
http://www.carcomplaints.com/news/20...t-tossed.shtml

The temperature quoted was 50F or 10C. The problem concerned corrosion in an intercooler when exhaust was recycled, so hard to see what it had to do with the DEF. Maybe the DEF still gets injected even when the main part of the emission control is de-activated? I read about this somewhere.

super7pilot

That makes no sense at all 107123210. The DEF is injected way down the line towards the rear of the exhaust system and isn't anywhere near the EGR system intake.

I swear though. Some people like the plaintiff seem to have money to burn on nutty law suits. If you don't want to pollute ride a bicycle.

Doesn't seem to have made her get rid of her evil 40MPG suv and buy another that gets 1/3 to 1/2 the fuel economy. That pretty much says all you need to know.

tuffcalc

Ahh - maybe I had this all wrong. Only EGR is shut off below 10c but DEF still doses sounds plausible.

Loving this GLK in any event. Coming from a GLK350 that was terrible on gas.

super7pilot

Yep! That is far, far more plausible a scenario.

We have owned ours since May 2014 (bought it while living in the Fatherland) Of course no car can be absolutely perfect, But we haven't had any major issues in 37K miles.

107123210

What doesn't make sense??

super7pilot

I was as clear as mud wasn't I?

That the DEF would shut off when it has a heater built into the DEF tank to help it work in the cold.

107123210

It's hard to find accurate information on just what gets switched off and how. Daimler said "that under certain circumstances, a system to treat
exhaust fumes could operate at a level of reduced effectiveness to
prevent condensation from building up in the exhaust system. The
condensation could otherwise lead to corrosion and damage the
effectiveness of the engine and exhaust system."

Elsewhere, I read about corrosion in intercooler due to acid in condensation that occurs when temperatures are low.

super7pilot

Information is hard to come by for sure.

There has been another conversation about front/rear tire diameter mismatch and the 4matic. Haven't been able to find any technical info on that system either. Just lots of anecdotal evidence, MB adverts & plenty of noise from internet experts.

Hugo L.

I had a warning light come on recently, telling me to top off the AdBlue.

I was out of town, but as soon as I got back, I did just that. I bought the car in August and have driven less than 5k miles. I suppose the system works, or I got the warning because the while thing froze.

Regardless, it's full now.

super7pilot

Hugo L. I take it you must do a lot of stop & go city driving.

Did you have MB fill it? You can do a DIY fill by buying 1 MB refill bottle then cutting off the bottom to act as a funnel for future refills. Then just buy the large DEF jug at your local walmart or auto parts store.

Hugo L.

Yes, about 90% of my mileage is to and from work in town. And as for the refill, I did just that!

RonTV

I took my 2015 Mercedes Benz GLK250 to Park Cities Mercedes Benz for emission issues. Two months later the same problem. Then Mercedes Benz sent me for a emission recall. I took it back to the same dealership to complete the recall but then two months later the same white smoke and the very strong ammonia smell. Then Mercedes Benz advised me to take the vehicle to Mercedes Benz of Grapevine Texas. Mercedes Benz of Grapevine told me that Park Cities Mercedes Benz of Arlington Texas didn’t do the emissions recall modification so they had to do it. A few months later I’m having the same DEF emission problem, white smoke with a very strong ammonia smell that I can’t park the vehicle inside my house garage. I’m still here wondering what the heck is going on with Mercedes Benz? They sent me a $3400 check for the recall modification so when I called up the lawyer he said that I can’t do anything because the recall is final. What can be done if anyone out there in cyber land can help me. My email is Lis.turner1960@gmail.com

bugelrex

What type of driving do you do 90% of the time? if its short in-town 5-10 drives here and there then the car never gets a chance to 'burn off stuff'. Try a 1hr highway cruise at 70mph once a month and see if it improves. But since you still under emissions warranty, just take it in. Find a dealer which has alot of sprinter vans in the service bay as they will have proper diesel mechanics