2005 Dodge Caravan Heater working intermittenly

If you can see no visible leaks and your adding coolant, you may have a leak internally. The cylinder head is attached to the block and a gasket is used. If any passage leaks through this gasket, and that includes oil, your cooling system will not be able to maintain the pressure it needs to deal with the heat properly. You can have an air leak. This causes the engine to burn the coolant through the exhaust. You may not see any white smoke but if your adding it all the time it may be that. Its called a blown head gasket. Your heater core becomes air bound. And this is a good test(heater) of your whole cooling system. It can be pressure tested. See the site menu for more information. Ok A 4 cylinder runs very hot and this is a common problem.

Hi, how are ya? There are only a few places that the coolant can disappear to. So I will tell you how I do any service regarding a 2005 4cylinder with 53,000 miles and no history, you were kind enough to bring your problem to this website, answer me, and here's how its done. First I would talk to you, then we would both discuss this vehicle, your main problem, and whether its worth any expensive repair. I would first show you my ASE ID and let you know how I like to help nice people like you get your van repaired, and do it reasonably. Your losing coolant, it needs to be pressure tested first, there are tools for this procedure. If the cooling system does not hold pressure(equal to the p.S.I. Rating on the original radiator cap, I would look for leaks. Also, I would test the cap, and since we have talked and drove it, I would trust you that your heater can work as long as this system would hold coolant and pressure. There are chemicals that detect combustion gasses inside the coolant for tiny, unexplained problem cars, or you can just start it up with the pressure tester on it, and watch it. Also, after the pressure drops, sometimes you can crank the engine and watch the coolant spray right out of the bad cylinder leak area. This is not to be done by anyone who has not done this before. Its dangerous. Now I call and discuss the overall reality and if you would want this service(remove cylinder head). From there it is an 8 hour job, this would include labor to replace the head gasket, thermostat, and lapping the cylinder head valve seats. If a crack is discovered upon inspection(this is the first step) I would let you know, from there I would talk about all the other items that need servicing now, while this head was off. If you say wait on other services I would finish, inspect, roadtest, bleed, and reset the computer.
Of course reading the vans codes would be part of our initial roadtest, ok.
So figure on about 8 hours labor and I would use about 130.00 worth of parts, this would include plugs and oil change. Of course I could be off on the parts price, but I would garantee this car for a full year. And I would always be honest about everything. 8 hours labor is a good rate. Warranty pays about 3 hours max.
So you can see why if a dealer does not support his technicians, no one who can perform these jobs, will stay. But that is not your problem. Any more questions about pressure testing and the other possible causes let me know. Thank 2carpros for the website. I am happy to help any person. I'm just a person, like you, who also had car problems. OK/ Oh and see if maybe the heater core is not leaking on the interior carpet. Pressure testing a cooling system is the best way for testing any leaks in any car, or light truck. Its explained perfectly on this website under 'how it works' and other do it yourself topics.
Its not a great idea to reseal a cylinder head if your mileage and age(van) is high, only because it may tend to be too much for the pistons and rings. But your mileage and age is pretty good. OK Joe