HI, I HAVE A 97 DAKOTA 5.2 4X4, THE TRUCK WAS NOT HEATING AT ALL, SO I ASSUMED IT WAS THE THERMOSTAT AND REPLACED IT. BUT STILL VERY LITTLE HEAT I NOTICED ONLY ONE OF MY HEATER HOSES WAS HOT, SO I BACK FLUSHED THE HEATER CORE, NOW I HAVE HEAT BUT MY LOWER RADIATOR HOSE IS COLD. I DRILLED A SMALL HOLE IN MY THERMOSTAT. THINKING IT WAS AIR LOCKED, BUT IT DIDN'T HELP. DO I NEED TO FLUSH THE RADIATOR ALSO?[:@]

 

You'll want to get one of those flush kits and flush the entire coolant system. That's what I had to do when my truck did that, except mine was overheating too. Anyway that took care of my issue.

 

I just had this problem on my BMW Z-3. You have a clog in you heater core or one of the lead in lines. You will need to run some presure through the lines and the core to flush it out. Consult you service manual for the exact amount of pressure.

 

Thanks YELLOWJACKET99, I'll try a flush kit, I am not overheating, I just don't like the idea of my lower hose cold, it should be at least warm right??

 

Adamdak, did you have heat at all when this started? I'm curious because now that I've been needing my heat in the winter I've noticed it isn't working good. The temp gauge works fine, and the temp is normal, but it doesn't seem to blow warm air unless I'm on the highway. Even then it doesn't blow hot air, just warm. The other night I started my truck to let it warm up, and it ended up running for 20-30 minutes before I actually ended up leaving my mom's house. I figured it would be nice and toasty inside, but it was still blowing pretty cool air.

 

You guys probably need new heater cores - something about dissimilar metals, electolysis, and gunk... it results in the core filling up with crap that you may or may not be able to force out back the other way. I replaced the core in my Ram a couple of years ago and I think it might be getting fubar'd again as my hot air isn't as hot as I remembered it being. Before I replaced it I could drive 30 minutes down the freeway before the cab would start to warm up, and that was mostly heat soak through the firewall and floor boards due to the engine and exhaust. At least in the Ram it's a 1.5-2 hour project, in the Dak it'll be more like 6-8 hours from what I hear.

 

another thing to mention is to use distilled water, prevents gunk from forming when using the 5 year antifreeze.