Dodge Repair Questions? Ask a Mechanic for Answers ASAP
Hello and thank you for you question,If you are not seeing any external leaks then you are likely dealing with an internal leak usually caused by a seeping head gasket. I would start first with performing a cooling system pressure test to check and see if there are any external leaks, if you don not find any and the pressure does not hold then the next step would be to perform a cooling system block test. Its a fairly easy test to run. The test checks the cooling system for any signs of hydro-carbons in the cooling system. You can get the kit to do the test at any parts store for about $20.00.
If it dose no pass the block test then that means the head gaskets are leaking and the fix would require removing the heads, having them checked to be sure there not warped and or cracked and the head gaskets would need replacement.
If the heads are cracked which is pretty rare, they would need to be replaced. If they are warped then the machine shop will resurface them and they can be reused. It may not require even this if its just bad gaskets. Before you get to concerned the pressure test as well as block test needs to be ran and it will determine which way you will need to proceed.
I would not go with used head and most machine shops will refurbish the head for about $250 give or take a few dollars and by doing so they come out just like new, the refurbish consist of planing if needed, valve grind if needed and magna fluxing to check for any cracks.
No if they do end up being cracked then you could go with used ones proving they are checked by the machine shop or you can also purchased re-manufactured heads all ready ready to install.
Its not likely a block leak but instead a head gasket or even a crack in the heads, most likely just blown head gaskets and to fix then you will need to start first with doing the block test, if after doing so and it proves the head gasket are leaking then I can provide the steps to remove them. Its your call, you need to get the block test performed FIRST.