I am having problems with overheating in my Dodge Caravan.
Problem: The temp gauge will go to halfway (which is where it normally sits) for a while but then after about 10-15 minutes (give or take 5 minutes) it will slowly (or relatively quickly) move towards hot. Sometimes it gets to hot, sometimes not and will generally stay there for a few minutes then work its way back down to normal. Today it got to hot so I pulled over and some coolant spewed out of the cap and more from the overflow container. Then after 5 minutes I checked the gauge and it had gone down to 3/4. I then started the car and made the short trip home. A couple of minutes later it was back to halfway/normal. The problem seems quite random but it does seem to be aggravated by working uphill or stuck in traffic.
The car does not appear to be losing fluid/coolant unless it gets hot and overflows. Both fans appear to be working correctly and work harder as the engine gets hotter. There does not appear to be any trace of coolant I the engine oil.
I have replaced the temperature sensor and thermostat.
Any ideas?