My 1.5 Diesel MK4 has an adblue range of 3500 miles after refilling it today. Seems like a really high consumption. I reset the MPG when I picked the car up in October at 14,000 miles and now I’m almost at 20,000. After doing nearly 6000 miles in 5 months, my average MPG is 60.1. I do a lot of motorway driving to and from work and just feel like this adblue range is really low considering my average MPG

It is what it is I'm afraid.

It's all down to how well and how much it's been "mapped" to spray.

Some cars last a couple of months, some vans weeks, lorries days.

My X2 does 15,000 miles on 10 litres

You'll just have to keep topping it up

I strongly recommend adding a bottle of anti-crystal on each refill

On 3/6/2026 at 7:42 AM, DaveT70 said:

It is what it is I'm afraid.

It's all down to how well and how much it's been "mapped" to spray.

Some cars last a couple of months, some vans weeks, lorries days.

My X2 does 15,000 miles on 10 litres

You'll just have to keep topping it up

I strongly recommend adding a bottle of anti-crystal on each refill

What make of anti crystal would you recommend

I bought the wynns one

19 minutes ago, DaveT70 said:

I bought the wynns one

I wonder whether it's really necessary if you're getting through a lot of Adblue?

One of my Golfs has Adblue, but I never actually drove that one. It's had the same Adblue in the tank for at least 3 years now. (4500 miles worth on dash). I was initially worried about it crystalising, so quite surprised to see that it hasn't so far, or at least I haven't seen any symptoms of crystallisation. Parked outside in all weathers, has seen extremes of both heat and cold. Not really sure what the 'ideal' conditions are for crystallisation.

It's supposedly more helpful for crystallisation around the injector nozzle too

5 hours ago, TomsFocus said:

I wonder whether it's really necessary if you're getting through a lot of Adblue?

One of my Golfs has Adblue, but I never actually drove that one. It's had the same Adblue in the tank for at least 3 years now. (4500 miles worth on dash). I was initially worried about it crystalising, so quite surprised to see that it hasn't so far, or at least I haven't seen any symptoms of crystallisation. Parked outside in all weathers, has seen extremes of both heat and cold. Not really sure what the 'ideal' conditions are for crystallisation.

adblue unused destroys the system - gout cleaner is a real need for slow use situations - tank level sensor and pipework / valves feeding forwards is the issue

fast motorway work uses the most adblue - as that's where its producing the most pollution - its trying to convert the death in to something far less dangerous to save our lives

slow speeds / gentle driving will use the least - hard driving / high speed motorway work uses the most

God's sake!

So the consensus is that my high motorway mileage leading to me having a higher MPG is draining my adblue tank quicker? 😂 the reason for a diesel car is high annual mileage and now I’m being screwed for it by having to constantly refill the adblue rather than doing slower speeds/normal driving which is what a petrol car is for? Makes sense 😂

I would slightly disagree with the above.

Adblue is about reducing NOx. NOx can only be created during lean burn (little fuel, lots of air). So motorway cruising will use more Adblue but only if you're cruising gently.

Adblue also only works when the exhaust is hot, so although a lot of NOx is created at idle, Adblue won't generally be used around town. EGR will used to control NOx around town.

There is a strange effect where very heavy use such as towing seems to rinse through Adblue. I can't explain the science behind that, but there will be some!