Am I right in saying that the only way a bellows thermostat can fail is when it leaks and it therefore will not expand when hot?
If a bellows leaks, it expands. This means that the thermostat fails in the open position - this was deliberate so that a failed thermostat would not boil your engine.
spot on!! VW also added springs to the flap system, so any other type of fail would also cause the flaps to open!!
Ultimate fail safe. Looks like 70 quid for a new stat. I reckon ours hadn't worked for years before, now the t/stat controls the flaps, back to orig!
ask about on vzi.. for an old type stat,[i got on from there] as the new stats don't open when failed, as they are a different design,
I have a new style one you can have if you want it. it is brand new and i have since sourced a second bellows spare. if you want the new style one just PM me your address and i will post it to you. it will make a good temp measure until you get a proper one.
genuine (fail safe) http://www.vwheritage.com/vw_spares...ntry_GB.htm?crumbStartPage=3&crumbStartRow=59 new style (not fail safe) http://www.vwheritage.com/vw_spares...ntry_GB.htm?crumbStartPage=3&crumbStartRow=59
I put mine into water which was just off the boil and there were a few bubbles which might indicate a leak or perhaps just air trapped between the folds? It did expand pretty well so maybe it's OK. However when I went for a couple of miles run this evening it didn't seem to expand as much as I thought it would and certainly did not fully operate the flaps. Is there a trick to adjusting it properly e.g. should I warm up the thermostat and then feed the cable into the flaps clamp or should it be done whilst engine and thus the thermostat are cold. I couldn't believe the price some people are charging for new thermostats - how can they justify £100 - £120!!!!
do you have the under tins fitted to the engine, as this has a big effect of how the thermostat works when driving!!
I fit the stat when cold... just push the flaps round on the bar... bit of a fiddle, but it is do-able... or unhook the fail safe spring, attach cable and re-hook on the spring
In defence of the "new style" ones (which are intended for Mexi type 1-engined beetles) - they're wax thermostats, more robust than the alcohol/bellows type, so less likely to fail. They're still not suitable for the standard t1 mounting bracket, tho', so stick with bellows. Can buy new 'uns, or plenty around second-hand. If the folds are squished together at room temp, they're fine and not leaking.
"Under tins" ? I have the tins which fit around the engine together with the foam seal but the only other tin I have is the one below the pedals. Can't say I've seen piccies of other tins, or even seen them in the usual suppliers' catalogs. Can anyone supply photos or say who supplies 'em. Mine is a '79 Cali import if it makes any difference.
you should have something that looks like this under there: It stops the airflow under the van cooling the thermostat, and the actual engine temp is contained around the stat
Nope - not seen anything like that underneath. Do you know if they're still available and if so where from. I guess that if I can get some it will be obvious how they fit? Don't spose having a t4 engine makes any difference - or does it? Many thanks for the advice/comments
I make those GRP copies made from original parts!! It's just a case of what heat exchangers you have fitted... UK, or US triangular flange ones (I don't make the latter as yet!!)
