1993 Cutlass Supreme With a 3.4. Which way does water flow through heater Core?

[Petes93cutlass]

I have a 1993 Cutlass Supreme convertible with a 3.4 engine. I need to flush the hear core because the car has very little heat blowing out of the vents. Yes, the coolant is at full level. I would like to know how the water flows in and out of the heater core in order to back flush it. You have one of the heater hose lines that follows the passenger side frame rail and clamps onto the waterpump neck. The other heater hose is by the master cylinder. So, does the water flow from the mater cylinder to the pump or from the pump to the master cylinder

[94 olds vert]

The water pump pumps the coolant in and the hose by the master cylinder is the outflow.

[Schurkey]

The water pump pumps the coolant in and the hose by the master cylinder is the outflow.

"In" and "outflow" of WHAT?

 

First Guess: The engine, not the heater core.

 

I have every expectation that the plumbing by the master cylinder--and therefore near the thermostat--is the heated-coolant source for the heater core. Having gone through the heater core, the cooled water returns to the suction side of the water pump where it cycles through the engine to warm up again.

 

 

 

 

 

If you have poor heat, check the thermostat FIRST. Way more common to have a stuck-open thermostat than a plugged heater core. For that matter, air-locked heater core is more common than plugged. I don't know how common air-door problems are; but if the ductwork doors don't work right, you might not get hot air to the interior.

Edited January 31, 2014 by Schurkey

[Petes93cutlass]

The thermostat was replaced when i rebuilt the engine 7k ago. i just need to know if the water flows from the water pump through the heater hose along the passenger side frame rail that goes into the heater core and out by the steel coolant line by the side of the master cylinder.The line you speak off that has the quick dissconnect connects to that steel tube that goes into the heater core

[Petes93cutlass]

The water pump , thermostat, and radiator are all brand new. The blend door actuators tare working properly. its 100% heater core. I just started flushing and it was pretty clear water both ways. When i put a cleaner in the heater and let it set for 15 minutes and then filled the line with water, I then used my air hose to blow it out and all kind of crap came out of the core

[Crazy K]

water goes from the fitting by the T-stat to the heater core. water returns on the pipe on the passenger side. flushing it both ways with a garden hose is easy to do.

I have done it plenty, using two extra tools, 1 an inline garden hose valve, and 2 a hose barb repair fitting, with a worm clamp. this allows you to attach your garden hose to the heater hose, and have control of flow. Flush both ways at least twice.