'16 Cactus - 1.6 HDi - Sudden white smoke, smells of urea / Adblue

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thetapeworm
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'16 Cactus - 1.6 HDi - Sudden white smoke, smells of urea / Adblue

Post by thetapeworm »

Long time reader, first time poster, apologies that it's to ask about an issue.

My wife has a 2016 Cactus with the 1.6 HDi engine that's currently showing about 48k on the clock, we did about 700 miles up and down the motorway over the weekend and some general pootling around with no issues to report at all.

We popped into the city yesterday, about 5 miles, no issues, about 3 hours later I set off back home and after about 5 minutes of driving accelerated down a slip road to get up to speed and then a few minutes later noted what looked like excessive water spray for the amount of rain coming down at the time. I kept going but then realised it was white smoke which got worse with revs.

I wasn't far from home and didn't fancy being stuck in the rain so took it steady, conscious of the white cloud behind me and completed the final couple of miles before stopping. On checking the "smoke" it's more of a vapour and has a really pungent smell of Adblue / Urea, the inside of the exhaust tip also has a light white residue on it but this may well be normal as I'm not in the habit of looking up there.

No warning lights (yet), car sounds and drives normally apart from the output from the exhaust. I haven't had a chance to check for codes yet and my garage of choice is booked up for the next couple of weeks and aren't really experts on these cars, it's just an honest local place.

It's definitely way beyond water vapour in the exhaust when the car is cold and to me the smell suggests it's just pouring excessive amounts of Adblue into the exhaust which makes me wonder if a sensor has gone that's causing it to just keep injecting it or if the injector itself is stuck open. Out of fear for causing any issues I've only had the 3 miles or so to experience the issue and then some time idling outside the house so don't have a lot to go on currently.

If anyone has seen similar, or has any thoughts or suggestions on what this might be I'd be really interested to hear about it, cheers.
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GiveMeABreak
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Re: '16 Cactus - 1.6 HDi - Sudden white smoke, smells of urea / Adblue

Post by GiveMeABreak »

Hi and welcome.

It's possible that it may be NOx sensor or the adblue injector. If the injector has an issue or is leaking, you may find white crystallisation around the injector area that will cause the urea to evaporate along with the steam - ot if it is over-injecting the same can happen internally - too much adblue in the system.

Either way it may be worth a visit to your dealer as they have been known provide some good will gestures with these - or you may just need the injector and or sensor replacement.
thetapeworm
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Re: '16 Cactus - 1.6 HDi - Sudden white smoke, smells of urea / Adblue

Post by thetapeworm »

Thanks for the welcome and the reply, I appreciate it.

We've had a few issues with other emissions systems on the car, namely the EOLYS injector sticking shut and during diagnostics for that it was mentioned that replacing any of the injectors for that or the Adblue system usually involve replacing entire systems at great cost so I was a bit worried this might be the case here but I might see what the dealer has to say, I've been reluctant to use them much as they never seem too willing to do anything until they've charged me £90 for a diagnostics check :)

Interesting to hear that there's a bit of history with this kind of thing and Citroen though, maybe I'll get lucky.
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GiveMeABreak
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Re: '16 Cactus - 1.6 HDi - Sudden white smoke, smells of urea / Adblue

Post by GiveMeABreak »

Additive pump is incorporated into the additive tank assembly so that is why if the tank runs dry which can lead to the additive injector failure, they have to replace the whole unit. Similarly, the Adblue tanks have all the pump and heating mechanism incorporated inside which is a sealed unit - so earlier tanks had to be replaced in their entirety.

Diagnostic time may be disregarded if they find the fault and you have the repair work undertaken their - or they may charge you the diagnostic tme and undertake the repair as good will - it really depends ont he year of the car, the mileage and if the car has been serviced regularly.

The diagnostics are required simply because the dealership have to follow a guided diagnostic procedure which involve certain tests to determine the faulty part and confirm the suspected fault. The report is then needed in order for the dealership to claim the labour and part costs back from Citroen Head Office who themselves may make a claim against the manufacturer of the component.
thetapeworm
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Re: '16 Cactus - 1.6 HDi - Sudden white smoke, smells of urea / Adblue

Post by thetapeworm »

Thanks again for your input, all interesting reading.

Having called Citroen it turns out there's a couple of outstanding items that need checking on the car anyway, the Adblue filler cap and something to do with the CAT so it's booked in on Friday for them to have a look at those and we'll see what happens with this issue at the same time. If nothing else it will be good to have the car diagnosed properly as to date I've tended to use local specialists out of fear for Citroen prices and probably spent twice as much :D
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GiveMeABreak
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Re: '16 Cactus - 1.6 HDi - Sudden white smoke, smells of urea / Adblue

Post by GiveMeABreak »

That is a distinct possibility and not surprising to be honest as local garages can't or won't spend money on training courses to keep up with the latest developments that the dealers have to do. So you pay a premium for this - but it can save money and potential disaster in the long run from those who don't know what they are doing.