... whereas before it was reaching 200F.
Ouch. So first mod might be a temp gauge with a thermocouple on the casing to warn of excessive heat, across a couple of cars to confirm a widescale issue.
Secondly some type of heat sink might help.
Or maybe strap one of these onto it?
http://www.amazon.co.uk/Galleon-Fireplaces-Powered-Stove-Burner/dp/B00BLHX4DQ (sorry HTML tagging disabled - link in case anyone wants to see what this is...)
