It's ironic but some have found after an all aluminium larger capacity radiator upgrade that the car runs hotter in certain circumstances typically motorway cruising I believe. Reason is the thermostat which remains partially closed for longer to compensate for overcooling. It messes up the hysteresis but a thermostat change solves I understand.
The 3.7 Roadsters John V6 and I have seem to have very robust temperature control as no difference at all after rad upgrade other than fan coming on far less regularly.
