Chevy Blazer
Heater Cores and Blower Fans
Car Heaters

You have a 2000 Blazer After installing the water pump the heater just blows cold air you have replaced the thermostat back flush the cooling system Both hoses that goes into the heater core are hot?


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2014-07-11 00:53:58
2014-07-11 00:53:58

vacuum operated valve in heater hose not opening


Another possibility is that the heater core is plugged. The Dex cool coolant is notorious for clumping up and clogging up the heater core when exposed to air for a while (air pockets in the system after adding in coolant)

Disconnect the 2 hoses on the firewall that run to the engine (heater core inlet and outlet). Take 2 pieces of automotive hose or whatever you can get your hands on the make a snug fit around the pipes coming out from the fire wall. run a garden hose on the right hose (outlet). Don't push the garden hose directly to the heater core. you can damage it. heater cores can handle pressure 14-16PSI on average, a garden hose can do 40-70PSI. you risk damaging it. Run the water into the hose and keep an eye out on the other one and see if coolant is flowing, you can push the garden hose closer to the outlet hose on the heater core if needed, just be careful. once you're getting clean water all the way through and no chunks or pieces are coming out. Reconnect the hoses from the engine and start it up. You'll have to add some more coolant to make up for what was flushed out.

If both heater hoses were hot chances are the heater is not plugged and there is no vacuum operated valve in the heater hoses on that model. My guess would be the temperature blend door actuator behind the dash has failed.

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Related Questions

The thermostat on a 2001 Blazer is just inside the larger or upper radiator hose. This hose connects to the front of the engine manifold.

Factory said to use a 195 degree thermostat

The Chevrolet Blazer cooling system diagram can be obtained from most Chevrolet dealerships. The cooling system diagram can also be found at most auto-parts stores.

The heater valve could be failing to open for one reason or another.

The thermostat in the 2002 Blazer will most likely be in the top radiator hose engine inlet, depending on the engine in the vehicle. The top hose is removed then the inlet unbolted to reach the thermostat.

Basically: when they are faulty.The original Thermostat on your Trail Blazer should last longer than the warranty, so 60,000 miles or more.Then the fun starts.There are poor quality cheap Thermostats out there that tend to not last longIf the cooling system is not maintained well and the car runs hot due to problems other than the thermostat the thermostat will fail immediately.If the wrong temperature rating is used the part will fail or not operate correctlyA cooling fan that is broken or not running correctly.ADVICE:Use a GM/DELCO brand part purchased from the dealer and watch for a hot running engine that will damage the thermostat.

There can be many causes of overheating. Clogged radiator, stuck thermostat, inoperable cooling fan, bad water pump, defective radiator cap, air trapped in cooling system, and blown head gasket.

You did not mention the engine size. Regardless, it is in the thermostat housing on the intake manifold.

follow the upper radiator hose to the thermostat housing on engine. Thermostat is located under the thermostat housing.

Follow the upper radiator hose back to the engine, it is connected to the thermostat housing on the engine. The thermostat is located under the thermostat housing.

Follow the upper radiator hose from the radiator to the engine. It is attached to the thermostat housing. Removing the thermostat housing will expose the thermostat.

The 2004 Chevrolet blazer 4.3 liter engine cooling system has a capacity of 4.7 gallons. The cooling system should contain a minimum of 50 percent antifreeze.

It could be a blocked heater core if your fan works... Or it could be your thermostat... I have an 03 that is doing the same thing. I just replaced the thermostat and it is still doing it. There is a site called you may get some better answers there

Plugged radiator Defective thermostat Low coolant Defective radiator cap Water pump not circulating water fast enough Cooling fan not working

depends on what temperature thermostat was put in. come in different temperature ratings.AnswerIf you installed the correct OEM thermostat, and did not install it upside down, then no, this is not normal. You should flush the entire system, check the water pump for proper operation, clean the radiator external fins, check the operation of the electric cooling fan, (If Equipped), and make sure you bleed the system to remove any trapped air.

Follow the upper radiator hose to the engine, the thermostat is under the housing the hose connects to.

Your 1999 Chevy blazer doesn't have a timing belt.

Did you check the thermostat to make sure it is working? If it is and you have enough coolant, you might want to check for head gasket issue. You can rent a tester at Autozone. HTH

The thermostat is located under the elbow of the upper rad hose on top of the intake manifold.

I hope this question is about the engine coolant thermostat. If it is and you have to ask this, you shouldn't be allowed near a vehicle with a tool.

The thermostat is located in the housing that the top radiator hose connects to, the bolts holding it on to the engine are metric.

on the intake manifold front of motor on top

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