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The C300d
Posted: Tue Sep 15, 2026
by ezra.olawaleer
Is it normal for the ad blue counter on my 2018 c300d to only decrease in increments of 100?
Re: The C300d
Posted: Tue Sep 15, 2026
by idris.saltmarshbo
I can't say for sure, but it makes sense given how infamously wrong the AdBlue remaining range indicator is.
But, be sure to check the dash and EML for any error messages. Regrettably, the AdBlue system shows no signs of reliability.
Re: The C300d
Posted: Tue Sep 15, 2026
by ezra.olawaleer
I value your response and am grateful for that. On this, I have read not one but two answers. one claims hundreds while the other claims nothing. Would appreciate any additional responses. Hopefully, it's working because at least it's going down.
Re: The C300d
Posted: Tue Sep 15, 2026
by tarquinrr
A 2016 250d descended in 100-mile increments. My fuel mileage and AdBlue records showed an interesting trend: on my frequent long runs, the full tank reading of 7,000 miles only decreased by 100 miles for every 300 miles covered.
At the local Esso station, I simply added more AdBlue and filled up one bottle of Forte anti-crystal liquid to each fill up to the 25% mark. The system functioned flawlessly for more than 100,000 miles. Perhaps the secret was properly stored and treated AdBlue, along with many long miles on the highway. Problems may arise on short trips around town when using old, stale AdBlue stored in the sun for refills.
Re: The C300d
Posted: Tue Sep 15, 2026
by ezra.olawaleer
It's great to hear from you. It does go down very slowly; I only put 4,000 miles on my car each year, so I thought there must be something wrong with it. Great advice, though.
Re: The C300d
Posted: Tue Sep 15, 2026
by talithaxujl
Where can I find instructions in the manual?