Hello,
I have a 2003 Grand Caravan Sport 3.3L. For some reason when I start my van and turn the heat on it stays blowing cold until the temp gauge reaches half way up and then the temp drops down to normal and THEN it starts to blow heat.
I made sure the antifreeze is topped right up.

In addition, my fans will not stop running.

Any ideas?

I heard there is a engine coolant temperature sensor that may have to be unplugged. Anyone know of that and if so...where is it?

Thanks

 

The fan relay or Engine temp sensor ETC or the A/C transducer are keeping the fans on.

 

I have the following issue with my 2007 Caravan. Just had the rad replaced cause it was leaking. Symptoms, while idling temp goes up to normal range. While driving, winter in Canada, temp gauge drops back to almost cold, I can feel temperature inside dropping off. I have replaced the Thermostat twice in the last week and still the same above conditions, idling temp goes up but drops back to well below normal after driving for a while. Anyone have any suggestions?

 

Keep checking your coolant level after changing your radiator. Air pockets can make funny things happen. Park facing up on a big uphill or on car ramps so that your radiator is much higher than your engine. This will chase the air easier to the cap. Hold it at 2500 rpm for a couple of minutes and then shut it off and let it cool before checking. If your radiator is full, and you cool down abnormally while driving, your thermostat is sticking open, no question about it. If your radiator is full and your thermostat was acting normally, you would have heat and a normal engine temperature at idle and on the road. Your thermostat is wrong, maybe backwards or upside down if that is possible I don't know. You heat up when idling because no airflow through the radiator. You take it on the road and it cools down because you have airflow through the radiator when driving. This tells me your coolant is running through your radiator all the time. If your coolant is always running through your radiator, you will never heat up enough. It is the thermostat's job to close and open only when engine temperature is high and allow some coolant to go through the radiator. Did you do the thermostat? Did you get a good one? Make sure it is the oem temperature, sometimes they make 185 and 195 degree ones. Sometimes crap brands make junky ones. Autozone or whatever will tell you which is oem temperature. Good luck.

 

Thanks mirageman and all, very good tips. Well I tried 2 Thermostats from Canadian Tire with no success so I went to the local Napa Auto and got one from them. I installed and filled coolant using the trick of parking on a hill. Rev the engine to 2500rpm for a couple on minutes. Temp gauge when up to shy of half, normal good running range. Then I took it for a good drive, low and behold temp gauge stayed at the good running range. So the bottom line was whether or not it was the thermostat or air bubble that was the cause of the issue. It's working now so I'm not going to play with anymore.

Cheers and Merry Christmas and a Happy new year to one and all.