Thermostat question 1.6td jx

[Laws1974]

Thinking of fitting a 80 degree thermostat instead of an 87 I have fitted is it worth it?
And has anyone done this! I have found a 75° thermostat but I think this might be to low.


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[Louey]

Why change from the original design?

[California Dreamin]

Ultimately a lower opening temperature thermostat doesn't give the cooling system any better cooling capacity, rather, the engine will run somewhat cooler on those shorter journey's because the main body of coolant is being introduced earlier.
When you 'presumably' want it to count (the engine coolant and oil both fully hot) the lower opening temperature won't make any difference at all. Under these conditions 'both' thermostats would be fully and continuously open anyway.
This is a CI (compression ignition) engine that relies on heat for combustion, fitting a lower temperature thermostat will likely create a 'longer' warm up period and lower fuel consumption with increased emissions during this extended period. Engines run best at between 90 - 95C and this is the normal running temperature, well above the thermostats opening temp. If you want to control the upper temp of your engine then you should be looking at the thermo-switch operating the electric fan, it is this switch that regulates the 'upper escalon's of engine heat.

Martin