Jake719

Title says it all, really. I noticed yesterday that the coolant in my reservoir is so dirty it's pitch black. Going to flush the system and put in new coolant, but does anyone know if that might be a symptom of a larger problem?

tjwalker

What is the history of routine cooling system maintenance on this XJ?

If it's been a long, long time.......that is the cause. You may need multiple cooling system fluid exchanges to clean your system. Coolant is extremely important in so many ways; servicing it is critical.

At the same time, consider a new 195 degree Mopar thermostat and replace every hose if they are original. If you have a breakdown on the road because of a cooling system failure leading to an overheat, you are going to have much bigger fish to fry. Maintenance is always cheaper than repair.

00t444e

If the cooling system is that bad, I would pull the radiator hoses off, take the thermostat out, flush the block radiator and heater core a few times both ways, then put it back together with the thermostat out, and fill with water and drive it for 5-10 minutes, then drain and refill, and repeat a few times until the water is finally clear. Then pull it all apart and flush everything again, put a new thermostat in, and refill with antifreeze.