Alde fluid - my plan

I cannot remember exactly, maybe about 3-4 litres before it stopped coming out,  it will depend on the layout of the pipes and radiators.  I collected the fluid that came out each time and then added the same amount of clean water and circulated it with the pump to mix.

This diluated the mix each time, do it often enough and you will end up with pretty much just water. 

Then I added concentrated Glycol, I used about 5 litres, it did not all go in at once, so I just ran the pump for a few seconds then drained out some more water and added the rest of the glycol, then any more topping up required I added water.

Took some spare glycol with us on the next trip, in case of air in the system,  but never  needed to top up again.

I was quite surprised!

Just to put my two-penn'orth in...

Have just had the fluid changed to the five year standard at Alde in Wellingborough, £150. I had cause to go because whilst away last week the heating and water failed to work on 230v but was Ok on gas; the pump was obeying the control panel as regards time and temperature but was obviously only pumping cold water around. My dealer was unhelpful - it was Ok when he serviced it the week before apparently - but gave me Alde's number. They couldn't have been more helpful but decided it needed to be booked in. The fault turned out to be the main connection into the Sargent electrical supply unit, a nine pin connector one of which served the Alde unit and, because it had worked slightly loose, had arced and hence not working. This is not the first instance of this I was told and now in newer vans the units are installed on their backs so as to facilitate ease of use/display reading etc, the sockets can more easily drop out. the van is 3 years 10 days old so no one is interested in warranty work!

Anyway, the fluid change was advised and as this was the first I had ever heard of the need to do this I readily agreed. I was not told of this 3 years ago and it had never been mentioned by my dealer on servicing and I cannot see any references to it in all the paperwork. You live and learn even after 25 years caravanning!

"You live and learn even after 25 years caravanning!"

Including a better understanding of the competence, ethics and culture of some of the dealers out there.

I wonder if the idea of empting the system and measuring the quantity coming out like we did in the old days when recharging a car's radiator system would work?.

On emptying, calculate amount needed and then half fill with the required water and then with the fluid. Running the system immediately will mix them together fairly quickly. Just an idea, would still need to faff around bleeding repeatedly mind.

The main problem is that using just gravity you only get out a few litres at a time, so to force out more old stuff you need to add other fluid, such as water,  as I described above.

Having viewed the procedure on utube I'm now convince I'd not tackle this much faffing around. Seems like you need that specialist kit to do it effectively.

Well, I did it this morning. Hardest part was getting the brass bung out, and replacing it.

Removed the bung and about 2 1/2 litres came out. I poured 2 1/2 Litres water into the header tank and let another 2 1/2 litres drain out.

I made a temporary bung out of a piece of dowel, bunged the drain pipe and put 2 1/2 more  litres of water in and ran the pump for a couple of minutes. Removed the bung and let it drain, the liquid was almost clear.

I poured about 2 lites of new red glycol in the header tank, looked at the draining liquid and it was just turning red.

Replaced the bung, it was tricky, awkward.

Topped up with new glycol, just about got the full 5 L in.

Having a rest now then will see if it needs bleeding.

Was the glycol diluted or full strength? What is the concentration now? 

I rang ALDE while I was in Halfords and asked which one to buy , he said 'ready mixed'.

Dont know what the concentration is now, but if it holds about 13 L and i put in 5L glycol then it is about 40/60 i hope!