Hi all.
I'm new to this forum, haveing much more experence with classic mini's & the ausmini forum. But I became involved with my brother-in-laws 1990 Caravell last weekend as it had decided to loose all it's Cooland between Bathurst & Portland about 8weeks ago.
My bother-in-law managed to get it back to portland (with frequent refills of the system) 25ks 2hrs where it remained until we could muster a retreval mission.

We found the marvilios sensor designed to monitor the coolant level failed due to the plastic fatigueing & ejecting the sensor from the Header tank. Thus looseing all the coolant it was monitoring the level of. YAY.
Anyone come accross this before??

Anyway as a result some enquireies have resulted in the opion that only purpule genuine coolant should be used in this car.
Is this true?
If so what is it about this coolant that is different to green coolant (other than the colour)?
Best Regards Paul.

its designed to slow head stud corrosion in this engine

yeah make sure you use the VW coolant as Barls says

Also the header tanks are a common problem and available from Vintage 9789-1777 if you need to get a new one, they have the coolant as well

yes the head studs are in contact with coolant all the time with this engine design so will corrode if (alloy/steel electrolytic corrosion) if the wrong coolant is used.

As for the plastic - that sux, but is why most car manufacturers specify all engine bay plastics and tanks etc be replaced at (for eg) 200,000km or 10 years

Yes I get that steel-allloy corosion needs to be inhibited, but what I am interesed in finding out is this chemical properties that make genuine purpule coolant so different (read $$$) from green Glycol coolant that is when used corectly inert or near to it.
Purhaps it better heat transfer characteristics as Green glycol is a poorer conductor of heat than water & is better at leaking through any small crack than water too. I belive some head gasget manufacturers specify running only water for the first 10k after haed gasget replacement ( I assume to be sure the head is well "bedded")

As for specifying all engine bay plastics be replaced at ten years or 200K sounds like sound egineerig pratice to me but how many of these manufatures have those parts avalible new 10yrs after the model has been released.

Anyway the car is mobile again but the spare that was souced from the very helpful people in Cambeltown (don't know teir name) has a slight difference in the conector facilitating the pluge to fall off a number of times between Cambeltown & Sydney. (I am unsure at this point whether this is because of the way my brother-in-law installed it).

The next issue will be getting the A/C going again before summer is over. Also ther is second Caravelle that may be becomeing avalible, In general are they troublesom vehicle. This one is a 1992 or 3 better nick & lower Ks

Thanks for the info so far. It is good to get less byased advice when playing with exotic cars.

Regards Paul

the coolant has been changed by vw so check with your dealer before filling as the old stuff will be fased out so get the new stuff now and halv the expence