I got a 96 Grand Cherokee and the coolant just dissapears... at a rather alarming rate. I'll fill up the reservoir up to the line and within 150 miles it's all gone. The car has no other problems besides this. Doesn't smoke bad, doesn't run weird, no leaks at all. Engine oil stays clean. Oh not to mention.. the car NEVER overheats... even if the reservoir is dry (I don't let this happen anymore).

How should I go about troubleshooting?

 

have you done an oil change and checked the oil coming out?

 

If if leaves no puddles then it is being burned. Check compression, look at the plugs for deposits of burned coolant, look for coolant in the oil and foam in the coolant bottle.

 

Assuming a stock tranny cooler, check the transmission fluid as well.

I think a cooling system pressure test is in order.

 

Good point......I forgot about the cooler......but normally you end up with alot of pink coolant......