jlambs

I have an 01 Grand Cherokee 4.0L 133K mi. overheating after driving about 15 miles and no heat at all.

Replaced radiator, radiator cap, thermostat and condensor. Replaced all antifreeze and burped system.

Started jeep with radiator cap off. Once engine warms fluid flows through radiator and expands. Starts overheating after 15 miles of driving temp gauge fluctuates quite a bit (from normal to 3/4.) Overfill reservoir bubbles but once system cools reservoir is completely empty and requires a lot of coolant/water.

Cannot find any visible leaks, both top and bottom hoses are hot. Passenger floor dry and no smell of antifreeze in cabin. No heat at all.

All ideas are appreciated.

the_big_h

A couple of thoughts here:
Do you continue to get air bubbles out while running? That is not normal, could indicate a blown head gasket. My experience with blown head gaskets always included a lot of white smoke out the tailpipe, but I guess that's not always the case. Check the condition of your oil also - is there coolant in the oil? If you continue to have to add coolant, it's going somewhere....
The 0331 head casting is notorious for cracks - I'm not sure what model years had these installed. Just having one doesn't mean is is cracked, but.... AFIAK the casting number is cast into the top of the head, just between the rocker cover and the intake manifold, about halfway back.

The no heat issue could be a couple things:
- Are both heater hoses hot? If so, perhaps the heat diverter door is broken. I understand some models have a problem where this door will break off inside, you then lose control of heat.
- If one or both heater hoses does not get hot, then you have a coolant circulation problem. You have not yet replaced your waterpump. If the impeller has come loose from the shaft, if won't pump, and you'll get overheating and no heat from the heater.
- Is the serpentine belt installed correctly? Pretty hard to get it wrong, with the diagram right there, but if it's on wrong, and spinning the water pump the wrong way, it won't pump very well at all.

GI-Jeepin'

I know this is an old pos but I had a friend who started his Isuzu Trooper on a freezing morning and drove 5 miles and his engine overheated. Long story short, his waterpumper impellers snapped off. His coolant, while being mostly water and old antifreeze actually froze. The impellers were submerssed in solid ice in the engine block.

If your getting no heat, the water pump either isnt pushing the hot coolant to the heater core OR there isn't coolant left in teh block to push. It's going somewhere.

E-Rok

sounds like your water pump took a crap or its pumping the coolant elsewhere