I drive a 2000 XJ with the 4.0l engine. My green coolant keeps vanishing from the reservoir. Got a pressure test done and found no leaks. Simultaneously, I've noticed significant orange splatter by the radiator cap. Looks rusty. See photos.

I've got a new radiator cap coming in the mail and am planning to do a coolant system flush and see if these help the system keep its coolant and stop splattering.

Any other ideas about what the orange splatter could mean? Anything else I should test or do? Been searching for answers online and across the forum but haven't found any yet.

 

When your green coolant turns orangey brown is because its getting cooked by the engine. You have a bad head gasket or cracked head. Just in case replace your radiator cap and put a clamp on the overflow hose everyone here swears you need a mopar radiator cap...ok...i run a stant or the one that came with the cfs radiator...never an issue for over 400k. Its up to you

 

The orange splatter is your coolant. From your description the chances are it's the cap leaking, and do a very thorough flush as that is a very rust stained orange. While you're at it, undo the heater core hoses and flush that both ways too, it'll be full of crud and you're heating will be improved.

 

What boxburn said! Be careful with the water pressure from your hose.

 

Thanks both. Really hope its not a cracked head or bad gasket.

I will get it flushed tomorrow at a trusted shop. Live in the city and don't have access to the space or hose to do it properly myself 😕