Engine operating temperature - lower than normal?

[franjo_66]

Just recently I noticed that my 230SL operating temperature now sits at between 140F & 180F (so roughly 160F) when the engine has warmed up and during driving.

Prior to this the engine always sat constantly at 180F whether in summer or winter driving.

We are now in the summer season here in Australia, so I guess it's good that it is not overheating, but is this something that I need to address?

Would the thermostat be the first course of action (it is two years since I replaced it with an MB one) or are there other areas that I should also check?

I'm assuming that the slightly lower operating temperature may not be ideal for engine oil?

Appreciate any ideas or suggestions !

Thanks
Franjo

[Shvegel]

Almost certainly a bad thermostat.  The thermostat holds the coolant in the engine block until it is hot enough to open and allow coolant to flow to the radiator.

[kampala]

On cold days (50F 10C) my 250 would not reach normal temperature even after two hours of highway driving. Changed the thermostat and now gets to operating temp in few minutes and holds there.   

[wwheeler]

Other than the obvious, the other issue with the engine never reaching 180*F, is the WRD may never shut off completely.

[franjo_66]

Thanks for the responses !

@ Wallace - Appreciate the call-out on the WRD !

Thanks & Regards
Franjo