AO Silver Member
Join Date: Nov 2003
Location: United Kingdom
County: Perth and Kinross
Re: Thermostat knackered or not?
Yeh, 16v thermostats are expensive. I just got one for my 1.8 and it was £36ish +vat. My running temp has risen from 70 to 75. Best just go to an Alfa dealer and quote chassis no. etc.
If you want to know the best way to tell read on.
Run engine to temperature and feel the heat in the heater hoses and make a mental note. Go back the next day (engine totally cold) and let engine idle to temperature. Periodically feel the temperature in the radiator to hose and compare against heater hose temp (heater fan off in case yuou try the return hose).
There should be no significant heat in the rad top hose until the heater hose is very warm. Note: there will be a bit of heat at engine side of hose, but this should not go all the way to radiator. The lower rad hose will probably get warm due to coolant circulation when thermostat is closed.
I also find that the 1.8 engine takes longer to warm than a 2.0.
Finally, use a good quality coolant. The new red stuff has no phosphates or nitrates so will not form sludge. Do not mix red (5 year), green (3 year) or blue (2 year) anti freeze. If in doubt, drain and fill with red (it has the best anti corrosive properties).