Hi, I've read the old threads and saw these cars can be difficult. Im having a bit of trouble with mine. I've replaced the waterpump, thermostat, rad, oil cooler and also both pipes that run to the oil cooler. I'm using ready-mixed vw spec coolant. I can feel water in all the pipes and when running I can feel and see water/air is getting through the thin hose to header tank (saw this often gets blocked off at the joint). The bottom rad pipe to thermostat is always cold. Top rad pipe gets hot. The hose running out the bottom of the header tank doesn't seem to warm either. Heater matrix pipes do get heat in them. The temp dial in the car gets to 90 degrees quite quickly, say 5 mins or less for dead cold at just idle. Whislt running the engine I am squeezing the top and bottom rad pipes pipes and have tried reving it to 2.5krpm too. Eventually the temp needle passes 90 and heads for 100 and at that point I turn it off and wait for it to cool back down. The fan does not operate at all and the whole process is lasting 10-12 mins before I shut off. Any ideas/tips? Does it sound like an air lock or dodgy thermostat?
If the lower hose remains cold the thermostat somehow doesn't open? The fan switches on at 95° but is placed quite low in the rad. If the water is warmed up without flowing through the rad, it doesn't get that warm. The coolant indicator is coming from the head I guess, which is hotter. Normally the coolant is cooled by the radiator and then there should be less difference.
Cheers and my worst fear right now as I have dumped the cooant twice already after fiascos with leaky hoses. What fun. Its been about 3 weeks waiting on parts to get this far. Labour of love aye.
Collect the coolant in a clean container and put it back using a funnel with a seeve. The question is, why does your replacement thermostat also not open? Are you sure the pump is running and the bells don't come from temperature changes? Is there no blockage in the lower hoses? Did you clean them?
It is strange. The car has sat for a while with no coolant (inside, not outside in the elements) awaiting parts. I did think about testing the thermostat before install but didn't do it. Hoses were washed through with water when I took them off. The waterpump is a new unit from avs spares - meyle I believe. It spins nicely in the hand compared to the original. I've drained the coolant twice and cleaned with a sieve. Will have to pluck up the enthusiams to do it all again The radiator- just a thought- i didn't check if water runs through it. Maybe it is blocked? It was from a radiator specialist also new.
Hmm radiator runs water through fine and the thermostat works when poured with boiling water (pic doesn't show much but it moved)
One other thing- the original thermostat is a vw item and says 82 degrees where as my replacement says 87 degrees. Assume it is the engine side that temperature triggers it to open rather than radiator side. Both are working in boiling water. Migbt try the original thermostat for fun. Also the thermostat i got through avs is a mahle tx 1587d and I note that on searching ebay that part no is listed as not compatible with the mk3 abf.
All done stationary. The car hasn't got the MOT yet. I just edited my other post whilst you replied- im not convinced the thermostat I have is the correct one
Also after running cold water on both thermostats the original closes straight away where as the mahle one doesn't really respond. Pic taken in cold water after boiling and the silver mahle one barely moves. I'm going to put the stock one back and and see how I go...
OK that worked changing back to the oem thermostat. Running for 20 mins now, bottom hose hot and temp stable at 90. Is running a bit lumpy at times but old spark plugs and not run in year. All smoke from exhaust cleaned up now. Fans haven't kicked in and temp started to rise after 25/30 mins of running. Will need to research next steps on fan testing
AVS are great. I let Andrew there know my findings (and to cancel my thermostat order) and confirmed it is the wrong one for the car. He is updating their website so great success all round. The mayle catalog said it was compatible but actually it is an 8v stat looking at the specs.
