Heater Problems Need Help!

99sablegirl · 12-14-2004, 03:59 PM

I new to this forum and I needed a place to ask a question. I have a 99 mercury sable with a 3.0 12 valve engine. Well it got cold here recently and I went to use the heater and found it not to be working properly. It will not get very warm. At low RPMs its almost as cold as A/C but at higher RPM say 2300+ it gets a little warmer but not like it should be. I can't even defrost the windows by letting it sit in the morning. I replaced the thermostat and flushed the antifreeze just with a waterhose and put new in. Still no change. The strange part is that the temp gauge is reading normal temps and it takes driving about 1-2 miles to get up to temp like it always has. Even when I start it to let it get warm in the morning the temp gauge goes up to normal but the heater is still cold. So does anyone know what might be wrong or have any suggestions.

12-14-2004, 05:07 PM

You have a blocked heater core.

Read these instructions, flush and backflush the heater core until nothing but clear water comes out. Also, make sure there's a bypass hose installed. Refer to my sig pic for a lame attempt at making a diagram of the bypass hose.

Here's a link to the instructions.

OMG it's freezing in my car!

12-14-2004, 03:59 PM	#1 (permalink)
99sablegirl Junior Member Member Number: 4403 Join Date: Dec 2004 Visit: My Garage Posts: 6 Trader Score: 0 reviews Rep Power: 0	I new to this forum and I needed a place to ask a question. I have a 99 mercury sable with a 3.0 12 valve engine. Well it got cold here recently and I went to use the heater and found it not to be working properly. It will not get very warm. At low RPMs its almost as cold as A/C but at higher RPM say 2300+ it gets a little warmer but not like it should be. I can't even defrost the windows by letting it sit in the morning. I replaced the thermostat and flushed the antifreeze just with a waterhose and put new in. Still no change. The strange part is that the temp gauge is reading normal temps and it takes driving about 1-2 miles to get up to temp like it always has. Even when I start it to let it get warm in the morning the temp gauge goes up to normal but the heater is still cold. So does anyone know what might be wrong or have any suggestions.

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12-14-2004, 05:07 PM	#2 (permalink)
Bob Gervais Guest Member Number: Visit: My Garage Posts: n/a	You have a blocked heater core. Read these instructions, flush and backflush the heater core until nothing but clear water comes out. Also, make sure there's a bypass hose installed. Refer to my sig pic for a lame attempt at making a diagram of the bypass hose. Here's a link to the instructions. OMG it's freezing in my car!