So just sitting here thinking.

As I understand things if your car is fitted with an Ad Blue tank should the tank run dry the car will simply not start? No limp mode, just not start so you would be stranded where ever you happened to be until the tank was refilled.

I have now driven 8000 miles in a year and am due for my third refil of Ad Blue. As I have a service plan this is no real problem apart from the in convenience of taking my car back and forth to the dealership.

Now my question is this, the Ad Blue tank has a sensor in it that measures the contents. The Ad Blue, as I understand it, is injected into the exhaust system and not the engine. So what is to stop you putting tap water into the Ad Blue tank? It won’t damage the engine or the mechanics of the car?

Would this work?

Jim

Add blue is cheap and sold at every service station, petrol outlet. Why bother with water when you can fill with the right stuff anywhere anytime? M16 SVD8 ,4.4 HSE with a few extras, Sold R50 , Wife SQ5 , BMW R1200GSW.

As I said, just a question....

your exhaust gas regulation sensors would probably notice leading to a DTC and shut the car of, if it ever would start anyway. I would not advise this, given the sensitivity of the sensors the DPF and catalic converter. You might be confronted with high repair costs RRS 3.0 SDV6 HSE Lux
RRS 3.0 TDV6 gone
LR 3 HSE V8 gone
DiscoveryII V8 Gone
Discovery 1 V8 Gone
Mustang Shelby
Alfa Guilia (classic)

When I was driving trucks in 2007 I got one of the first trucks (Daf) with it fitted,,the company got 3 new trucks & we used to just top them up with water till the truck companys got wise to it then in 2008 one of the drivers got a new truck put water in it & it detected a problem & went into shut down.

Andy Andy.
21 Ford Ranger
Gone but not forgotten
Focus RS Red Edition
2015 RRS AB Fuji.
2014 RRS SC Santorini
2016 VW Amarok
2014 RRS AB Fuji
2012 RRS Red Edition Fuji
2015 Nissan Navara
2012 RRS SE Santorini
2008 RRS White
2007 RRS Santorino

Blimey third top up in 8000 miles

is that the norm, I know it depends on what sort of driving you do (town/motorway) but ours still has a range of 13000 miles showing and not topped up in 3000/ 6 months

at least you can get a coffee and cake with the visit to the dealer

 Porsche Cayenne 2022
gone Porsche Cayenne 2020
gone Corris Grey HSE Dynamic 2016
gone Ipanema HSE lux 2010
gone Rimini HSE 2005
!!

The DPF is upstream of the SCR catalyst, so that would be unaffected by water. However, there will be NOx sensors both upstream and downstream of the SCR catalyst, so these would read zero NOx reduction if only water was injected, despite the ECU looking for some difference in the values from the sensors, before and after. I suspect that this would raise a fault and bring on the engine MIL light. I am not sure of the JLR protocol for what comes next, but probably a derating of the engine to limp-home mode. Then the next time a cold start is attempted, it would not start. That is pretty standard across the industry.

SCR is very efficient at controlling NOx, about 90% reduction, making the emissions as clean as many petrol cars, despite what you hear in the press. Without adblue, the NOx emission is probably worse than a 10 year old Euro 4. Why would you want to do that? I would suggest getting your own Adblue and avoiding the grind of trailing to the dealer periodically.

Adam..

Last edited by Black Bess on Thu Apr 05 2018 9:21am. Edited 1 time in total

Or a visit to the local pig farm

30 months
22000 miles
Not a single ad blue top up.

But having said that my car has spent 50% of its life in the workshop so probably gets topped up by the dealer all the time which is why I have never had to do it myself. One of the great perks of owning a LR. MY16 (65) RRS, HSE, White, 21" 507s, Pan/Black Roof, 7 Seats, Ebony/Cirrus, Surround Cams, Fully Color Coded

I didn't even know it had Ad Blue.. do all L494 MYs have it?

No, not before 2016MY IIRC. My March 2015 build doesn’t have it 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW

From Sept 2015 (MY16 cars) 2016 RRS 4.4 TDV8 Autobiography Dynamic in Montalcino Red and Stealth Kit

or in other words, just the Euro 6 engines.

At Euro 5, DPF was effectively mandatory (the limit being 0.005grammes/km particulate) but NOx could be controlled by EGR alone.

At Euro 6 it is a very different story; the NOx limit is 0.08grammes/km and the only way to get there with a diesel is to use SCR (selective catalytic reduction) with ammonia (liberated from urea in the Adblue, also known as DEF) as the reductant.

JLR did a very good job with Euro 6 and achieved compliance over real-world drive cycles, not just the very stylized NEDC.

That compliance will now need to be demonstrated over the tougher WLTP drive cycle and proven on-road with the new RDE test requirements that now form part of European type-approval.

My MY17 had its third top up at the annual service having done 8500 miles.