2004 Chevy Suburban

[bpopilek]

So yesterday my truck decided to start giving me fits right after it finally got extra cold and snowy here! I'm hoping someone could give me some advice. Here is what I've done and where I am at.

I noticed early on this fall that my water pump was leaking, so I replaced it. I also found that my truck only blew hot air while in motion, and cold air while it was stopped or at idle. At this point I replaced the thermostat and housing. I originally had the stock setup with the combined thermostat and housing. The new one is and updated GM version with the separate thermostat and housing assembly. Everything seemed to be ok until yesterday morning.

This is where my problem is now. Yesterday on my way to work, the message center said my coolant was too hot. The temp gauge showed the truck at about 250 degrees. My speed was only about 45mph and it was 6 degrees outside. I ended up parking the truck and looking at it after work. I found it was still doing the exact same thing. When I investigated further, I found that the upper radiator hose was hot, while the lower one coming out of the thermostat housing was cold. At this point I figured that I had a bad thermostat, and bought a replacement. I tested the old one on my stove top in a pan of water and found that it did actually open at about 175 degrees, so I'm not so sure it was bad now. With the new thermostat installed, the engine is no longer overheating and the temp stays around 235 while driving. However, I am back to the heater blowing cold air at idle and while stopped, and warm air while driving. In addition, the rear heater now only blows cold air, it never warms up.

Does anyone have any ideas of what could be causing this? Any suggestions on a repair? I am at a loss and would prefer to fix it myself instead of having to pay the dealership. Thanks for reading and for your thoughts.

[777stickman]

I'm guessing that you still have air in the cooling system since the water pump change. With the lower hose being cold could also indicate a plugged radiator.

Several years ago I changed the water pump on my '98 Sub. Took 2 weeks of parking nose up and down to get the air out. After that the rear heater worked great.

Are you checking the overflow tank every morning for being full?

[j cAT]

Originally Posted by bpopilek

So yesterday my truck decided to start giving me fits right after it finally got extra cold and snowy here! I'm hoping someone could give me some advice. Here is what I've done and where I am at.

I noticed early on this fall that my water pump was leaking, so I replaced it. I also found that my truck only blew hot air while in motion, and cold air while it was stopped or at idle. At this point I replaced the thermostat and housing. I originally had the stock setup with the combined thermostat and housing. The new one is and updated GM version with the separate thermostat and housing assembly. Everything seemed to be ok until yesterday morning.

This is where my problem is now. Yesterday on my way to work, the message center said my coolant was too hot. The temp gauge showed the truck at about 250 degrees. My speed was only about 45mph and it was 6 degrees outside. I ended up parking the truck and looking at it after work. I found it was still doing the exact same thing. When I investigated further, I found that the upper radiator hose was hot, while the lower one coming out of the thermostat housing was cold. At this point I figured that I had a bad thermostat, and bought a replacement. I tested the old one on my stove top in a pan of water and found that it did actually open at about 175 degrees, so I'm not so sure it was bad now. With the new thermostat installed, the engine is no longer overheating and the temp stays around 235 while driving. However, I am back to the heater blowing cold air at idle and while stopped, and warm air while driving. In addition, the rear heater now only blows cold air, it never warms up.

Does anyone have any ideas of what could be causing this? Any suggestions on a repair? I am at a loss and would prefer to fix it myself instead of having to pay the dealership. Thanks for reading and for your thoughts.

the oem style , ONE piece thermostat I purchased last year , is the same one as the 2000 and 2004 thermostats ..two piece sounds like wrong part.

temp should gradually rise to 190 deg f and lock in.

with this type engine you fill as much a possible by using the top radiator hose disconnected at the top radiator connection. then you start engine and contiune to fill plastic coolant tank while reving the engine to 2,ooorpm occationally to get the air out until engine at the 190deg f.

these thermostats are at advance auto for 20-25.oo with a lifetime warrantee, and they work correctly.

[mishalah]

Originally Posted by bpopilek

So yesterday my truck decided to start giving me fits right after it finally got extra cold and snowy here! I'm hoping someone could give me some advice. Here is what I've done and where I am at.

I noticed early on this fall that my water pump was leaking, so I replaced it. I also found that my truck only blew hot air while in motion, and cold air while it was stopped or at idle. At this point I replaced the thermostat and housing. I originally had the stock setup with the combined thermostat and housing. The new one is and updated GM version with the separate thermostat and housing assembly. Everything seemed to be ok until yesterday morning.

This is where my problem is now. Yesterday on my way to work, the message center said my coolant was too hot. The temp gauge showed the truck at about 250 degrees. My speed was only about 45mph and it was 6 degrees outside. I ended up parking the truck and looking at it after work. I found it was still doing the exact same thing. When I investigated further, I found that the upper radiator hose was hot, while the lower one coming out of the thermostat housing was cold. At this point I figured that I had a bad thermostat, and bought a replacement. I tested the old one on my stove top in a pan of water and found that it did actually open at about 175 degrees, so I'm not so sure it was bad now. With the new thermostat installed, the engine is no longer overheating and the temp stays around 235 while driving. However, I am back to the heater blowing cold air at idle and while stopped, and warm air while driving. In addition, the rear heater now only blows cold air, it never warms up.

Does anyone have any ideas of what could be causing this? Any suggestions on a repair? I am at a loss and would prefer to fix it myself instead of having to pay the dealership. Thanks for reading and for your thoughts.

So, did you "burp" it, and did it fix the problem?