early 911 runs hot

[GIBSON]

I have a 73 911S with approx. 95,000 miles, 30K on a rebuild. In just about any weather it runs between 190-210 or a little more. It does not have A/C, no front cooler. I have removed the engine shroud and cleaned the cylinder fins and cleaned the oil cooler. I replaced the thermostat with another one I had around the garage, no difference. (I think the thermostat is working as the temperature stabalizes at 180 for a few minutes and then starts to climb.)
It will drop during downhill runs but then start back up again. The oil level is fine and the engine is not running lean.
I'm not that concerned that damage is being done as this is not that high, it's just higher than other early cars I've owned.
Any thoughts?? Thanks

[Bill Verburg]

190-210F is optimum and quite normal. If that is 190-210C you're in for some big repair bills.
Normal behavior for the temp is a slow increase to about 80C(175F) it will stabilize there as the engine mounted cooler does its job, when that becomes insufficient the fenderwell mounted thermostat will start routing oil to the front cooler, oil temp will then slowly climb to the range you have indicated 100C = 212F. you want the oil to get just warm enough to boil off any condensates which have formed inside the oil system(220 is desireable for this reason). If the temp never or rarly gets above 100C(212F) you need to change oil more frequently.