Which antifreeze for Alde system.

Advice taken from Alde's website concerning antifreeze:

Ethylene glycol (aka mono ethylene glycol, MEG, and ethanediol) antifreeze is also used in engine radiators, and is commonly available from service stations, car accessory shops and online retailers, concentrated or ready to use.

Do not mix antifreeze containing silicates with antifreeze containing non-silicated OAT.

Hope this helps.

All Alde require is a g13 spec so why not?

I notice it is concentrate so easy to use.  This is the concentrated version. Which requires diluting 50/50 but would workout cheaper 

G13 concentrate

The dilution required is conveniently one part concentrate to one part water, ie 50%/50%, however a ratio of 40% product to 60% water is also fine, just a bit more of a fiddle.

By going the easy way of 50/50 it leaves owners free to make small top ups with water a convenient solution without carrying any product around.

Re water; apart from the normally avoided detrimental issue that water hardness can throw out calcious deposits on the all important hot bits, it can reportedly also lead to some destabalisation or shorten the life of the critical anti corrosion additives.

So I would only use deionised water for filling the system, and for routine topping up. If requiring an emergency top up where I had not access I would as I have in similar cases used a small amount of pre-boiled tap water. Being fastidious here I know but we have a very expensive boiler that IMO for me is worth treating with best industry practice.

Products meeting both the VW specifications G13 and earlier G12 ++ [those +s being important] whilst very good have the feature of being tolerant to be mixed with nearly every other type of auto "antifreeze" we meet in Europe. They are thus the lowesr risk ones to use where we don't know what we have or getting it is challenging. The issue is all to do with incompatibility of the various corrosion inhibitors, destabilising them and throwing out percipitations, both best avoided.

Boff:

The van we have is the Hymer “S class” the 546 S of 2007/8, without in-floor heating.

There is a capped off quarter turn drain tap directly under the boiler access from under the van. It is brass and in road spray area so finger tightened cap tends to jam up. Mine also has mover under it making life difficult and needing mover to be covered in polythene sheet.

There are two bleeders port and starboard right up front, the starboard requires unscrewing the seat base plywood.
Still at the front there is another under the wrap round seating on the starboard flank. This requires removing the under seat section of the wall doubler panel and with the above seat ply removed.
No other along the starboard flank.
Along the port flank there is one under the hob, accessed by clipping out the under hob draw.
Then another only a foot away under the sink, again accessed by clipping out the draw there.
Then into the bedroom just aft of the bulkhead there is a ready accessed one.
Finally across the rear under the French bed there is one on the starboard side. With access to all

With access to all these bleeders priming the system is dead easy, untill I found that awkward one under the wrap round front seat it was not.

Mine takes almost all of 5 litres of concentrate mixed with 5 litres of deionised water. Draining needs a bit of blowing through, I used a vacuum cleaner with blow feature.

I used on the last change Comma GG40 a G13 spec product with 5 year life and one my local motor factor stocks.

Hope that insight into Hymer's thinking helps with your van.