94 Voyager heating problem

I have had this 3.0 liter van for many years with the only trouble being poor heat.Below are what I have checked or changed with no noticable improvement. Any additional suggestions?
1) Thermostat( a couple times)
2) Changed heater core
3) Checked cable throw for the blend door.
4) Checked manifold feed pipe for the heater core.
5) By passed valve in heater feed hose.

The unit blows good heat when being checked in the driveway with the all the heater hoses hot. The temp guage is stable at all times.
The trouble is when driving the car in the cold weather (-25) the heater just seems to change to luke warm. I'm getting too old to be cold.

I have had this 3.0 liter van for many years with the only trouble being poor heat.Below are what I have checked or changed with no noticable improvement. Any additional suggestions?
1) Thermostat( a couple times)
2) Changed heater core
3) Checked cable throw for the blend door.
4) Checked manifold feed pipe for the heater core.
5) By passed valve in heater feed hose.

The unit blows good heat when being checked in the driveway with the all the heater hoses hot. The temp guage is stable at all times.
The trouble is when driving the car in the cold weather (-25) the heater just seems to change to luke warm. I'm getting too old to be cold.


I dont drive in such cold weather, but the first thing that comes to mind is that if you have good heat sitting but it gets cold while driving you might think of a cover of some sort for the radiator grille to help keep the sub zero wind from cooling the coolant down.

Just a thought

just a quick note when u drive down the road the thermostat controls heat to predetermined temperature if the temp is fine in driveway and you loose it going down road either its low on coolant or thermostat isnt controling temp or line to heater core or heater core plugged and when u force coolant throught it wont go?

just a quick note when u drive down the road the thermostat controls heat to predetermined temperature if the temp is fine in driveway and you loose it going down road either its low on coolant or thermostat isnt controling temp or line to heater core or heater core plugged and when u force coolant throught it wont go?also an air blockage will cause same type of problem have you had the vehcile checked for a leaky head gasket? could be compression forcing a air blockage.

KRA,

Did you figure this one out yet? I am newly registered; I had a similar problem...had one idea.

KRA,

Did you figure this one out yet? I am newly registered; I had a similar problem...had one idea.

Hey now I am knew here and I wanted to know how you fixed the blend cable? I have a 94 grand voyager and if you set it to vent it lasts a couple of mins and then it switches to defrost. just this last sunday I stopped getting any heat and you can't hear the switch from vent to defrost any more, any suggestions, you sound like you have just about replaced it all!

No I did not figure it out. The van has been parked for the winter and has become a summer vehicle for the kids. Good luck and let me if you figure it out.