Invisible coolant leak - RWD - EGR Cooler removal - best method

I have a Crafter 2019 RWD 140ps, with a coolant leak issue, but no visible signs of a leak.


I need to 1) pressure test the EGR cooler, 2) then remove it if necessary.


The Workshop manual instructs one to remove the engine for EGR cooler replacement, a TIKTOK vid shows just this, google:

TikTok - Make Your Day



... however the comments say otherwise, access from below, some suggesting removing gearbox.


I will try going in from the top - if someone has already failed - I am all ears.


I have previously removed an EGR Cooler from an older model crafter (2018), with engine in situ, which was in a similar position ie up against the bulk head.
I removed most of the obstructions on the top of the engine to get as clear a run up, and mostly working blind with mirrors and some extra tools bought - ie extensions, stubby ratched spanners etc, removed and cleaned the cooler.
I replaced it by gluing/grease captive held the nuts in the socket/spanner to replace - I literally had to get half in the engine bay to do it, a pig of a job, but done.
The 2019 has a lot more going on on top of the engine, the Mahle Turbo Cooler and all the coolant pipes need to be cleared, and the cabin air intake cowl, my concern is the clearance behind, to slide the cooler backwards off the bolt 'studs', although the TIKTOK comments indicate that should not be a problem (ie engine can be left in situ).


It is using just a few 100ml every 2/3 hours of motorway driving, so a small leak. it has just used 4 litres of coolant on a trip to the Scottish highlands from London, so roundabout trip with some diversions around 1300 miles.
How much damage is being done I am not sure, I presume the water content of the coolant would be similar to driving on a misty morning, but the ethanol in the coolant might be another matter, I will presume at such low loss its all being evaporated, there is no sign of power loss, white smoke etc, although regens seem to be happening quite regularly, I hear coolant is not so great for ones DPF ... this video explains a little what could be happening:


[URL unfurl="true"]https://www.facebook.com/darksidedevelopments/videos/is-this-the-worst-20-tdi-engine-vw-ever-built/304502744181698/[/URL]


But guess it depends on how much coolant is being lost, some warn against hydrolock, but that would need to be much more than I am losing.


I initially put UV dye in the coolant - and looked in the dark with a Blue LED light, but saw no trace of a leak.


I have also ordered a coolant exhaust gases tester, to see if this is a head gasket issue, to help illiminate that from a diagosis.


It is suggested that with small leaks, the egr cooler is resealing when the engine cools, and if a hissing can be heard when the engine has cooled, when removing the coolant bottle lid, then that is indicative of such a crack in the EGR cooler that only opens when the engine is warmed up.


As an aside - who decided to put the ADblue/DEF pump and its vulnerable 'stalk' right at the bottom of the vehicle, and protect it with just a flimsy plastic cover, mine was cracked by the previous owner, driving round a quarry or similar - this is a commercial vehicle, I would have thought the underside would have been better protected, and delicate parts such as this placed in a better positionn.