Originally Posted by coalsmoke
Does anyone have any ideas at all? We took it to Ford, but they were completely baffled. We tried putting in a higher temperature thermostat, but it actually got a bit worse (colder). Now we're totally baffled too.
I have the same car, coalsmoke, 95 Aerostar, and the same problem. Mine is the extended van with the 4.0 liter engine, All Wheel Drive. My temperature gauge hangs in around the N of the normal range, which isn't normal. On a recent long trip, the check engine light came on, and my mechanic said that this may be due to the engine not running at proper temperature. He replaced the thermostat, and nothing changed. I am taking the car back to my mechanic for him to put in a higher temp thermostat, but now I am wondering if that is the problem. Here is one possibility: I understand that changing the thermostat on these vans is no easy task, and it is possible that our mechanics are faking it, not actually doing the work, figuring the car runs a little cold and this is no big deal. I live in California, and heat isn't a big issue here. In reality, the thermostat is stuck open and the car is running cold which is bad for the engine, reduces gas mileage, and effects the heater. Second possibility, the thermostats are being installed wrong.
Where does your temperature gauge read?