What I have been finding is cars that chronically run a low engine temp tend to have the following issues:
1. Poor fuel economy
2. More chance for sludge buildup in crankcase due to oil not able to "cook" off additional water vapor and excess fuel dilution. Cars that have shorter drives are more adversely impacted. This also accelerates engine wear as well.
3. Greater carbon build up in cylinders on piston domes, in intake ports and on rear surface of intake valves. Carbon that has been "cooked" acts just like a sponge. After the engine is shut down and the carbon dries out, at the first start of the day the carbon acts as a sponge and will absorb fuel until the carbon is wet to the point it will not absorb additional fuel. During the point the carbon acts as a sponge, it will lean out the fuel mixture causing lean misfiring, unstable engine idle and possible stalling. Once the carbon is wet, it is almost like it does not exists. This is why many times if the engine runs poorly on cold start, then stalls, on restart the engine may run just fine, the carbon has absorbed all the fuel it can and will no longer lean out the fuel mixture. On these engines with 3 intake valves the challenge is a bit greater.
What I have found when the engine has been running chronically cold, if a new thermostat is installed and you run 4 Techron treatments things will start to improve over time as you continue to drive the vehicle.