I hear water slushing in my dash board when only when I turn my car on. I've recently replaced my Thermostat and Replaced my Radiator. My heating doesn't work as well. Is it bad for your engine and how can it be fixed? Thank You!

 

You most likely have a clogged drain for the evaporator/heater core box. I'm not sure exactly where it's located on a Grand Cherokee. My Cherokee's drain is on the lower right side of the firewall. Anyway, make sure the drain is clear. But this won't affect your poor heating situation.

 

X2 on a clogged HVAC condensate drain letting the HVAC box fill with water causing the sloshing sound. The water can partially cover the heater core affecting heater performance. The drain is in the engine compartment on the pass. side. It's a black rubber elbow pointing down right above the frame rail at the firewall.
Dan

 

I have the same issue on my Grand? Is there just a plug to pull and let drain or are there other steps?

Ok I just started reading the thread a couple post below this one about this very same topic. It seems like a big project. Would a radiator flush acomplish anything on fixing this problem.... I worked at a Jiffy Lube and did them all the time. I also noticed on the other post people were saying their heater wasnt working that great, in my case the A/C isnt working that well, but the heat it fine.... Ideas, thanks.

 

Here's a write-up about the drain. http://www.aircondition.com/tech/questions/4/