My 2008 dodge caravan has an engine code for low coolant temp. I replaced the thermostat with an after market brand. Cleared the code. It did no good. When the outside temp is low 30's, the temp gage does not move & eventully the flow computer fault synbol appears. The van runs fine. When the outside temp is in the 50'& up, the gauge will move to about the 25% mark. (Normal has always been about the 50% mark). If I drive in slow heavy traffic or around town, once I turn it off, it is reluctant to crank. It acts like it does not want to turn over. If I give it some time, it will crank fine even though it is slower to crank. I have had it at the Dodge dealership twice with no results. Could the after market thermostat be causing this? I have suggested a bad sennsor but the dealership does not think so. Any ideas?

 

Seriously? There are some problems, such as misfire, which have lots of variables and can be time consuming for even a pro to figure out. But the cooling system??? It's hard for me to understand how a competent professional mechanic wouldn't be able to diagnose and fix this problem the first time. Two failed efforts is just sad. Did they provide a list of what diagnostics they did? If so, did they remove the serp belt and check all of the pulleys in the loop? If you have an independent shop nearby, I'd strongly recommend going there for your next try.

 

I believe they simply read the codes. The first time there was a serious problem, I saw steam coming from under the hood while I was parked idling. I raised the hood & coolant wss poring out the over flow. I shut it off & then it would not crank. I waited about 30 minuted , it cranked. I took it straight too the dealership. They said a radiator hose was not fully tighten which caused the problem. I still do not understand. The only hose that that had been loosed was when the thermostat was replaced.

After I picked it the next morning, all of the codes came back on within ten minutes of driving. Temp needle still did not move.

I needed the van so I decided to just drive it until I could put it back in the shop. The weather has been unusually warm in this area recently, the temp needle has moved up to the 25% mark with slow heavy intown driving. After driving it around recently, I turned it off & tried to restart it immediately. It barely turned over. After time, it would start but seemed a little balky.

I took it back to the dealership. They kept it two days. The only diagnosis was that the thermostat jiggle valve was upside down. After driving it, I have no confidence it is fixed. After turning it off, it is balky on immediate restart. It has been warm so the low coolant temp light did not come on.

I would consider a bad water pump or belts, but I cannot reconcile a low coolant temp & then it seemingly running hot. I know the fan works because I have witnessed it cycling on/off.

 

I agree you must have poor mechanics . Temps are directly controlled by the thermostat, if they actually replaced the stat then that should have fixed it or the temp sensor is faulty.

 

Has the dealership looked into your aftermarket thermostat? Also, are there any other nearby dealerships you may be able to bring your vehicle to for someone else to take a look at it?