[NOSIRRAH]

Parts replaced due to no heat: Heater core, thermostat, water pump, coolant flush.
Unmolested motor, 120kms (75M)
Drive for 10 minutes or so and the heat gauge is pinned to overheat. Pull over to cool down, drive back home, again overheat.

??
Possible airlock in coolant system
Broken new water pump
Head gasket leak (not likely)
Flushed crap stuck in the rad or the new heater core

Before I start any frustrating work, I wanted to ask you guys in case I'm missing something obvious or something specific from past experiences.

Talk soon, Thank you
Robin

 

[91ss]

How'd you purge the air out of the system? It's not a simple fill and go.

 

[NOSIRRAH]

How'd you purge the air out of the system? It's not a simple fill and go.

My father had a reputable shop do the work, so I have to 'assume' it was done correctly. Is this something I can perform again to ensure the air is in fact removed?

 

[91ss]

There is a little bleed valve on the thermostat housing. Takes a few cycles of letting air out. And use a rag to avoid any water hitting the Opti spark distributor.

 

[crazypirate]

There is a common head (flat blade screw driver) screw on top off the thermostat housing..two ways to bleed easily...1. Turn screw 1 full turn, start engine until solid stream, tighten screw and turn off engine..Try and keep anti freeze off Opti...2nd way..loosen thermostat screw, take off over flow cap and blow into it to pressurize tank/system...tight screw after decent stream out of bleed hole..keep it off the Opti..(no, it won't kill you.lol)..

Then take it out for a short drive..once Thermostat should be open, step on it and force rest of air thru.

 

[NOSIRRAH]

There is a common head (flat blade screw driver) screw on top off the thermostat housing..two ways to bleed easily...1. Turn screw 1 full turn, start engine until solid stream, tighten screw and turn off engine..Try and keep anti freeze off Opti...2nd way..loosen thermostat screw, take off over flow cap and blow into it to pressurize tank/system...tight screw after decent stream out of bleed hole..keep it off the Opti..(no, it won't kill you.lol)..

Then take it out for a short drive..once Thermostat should be open, step on it and force rest of air thru.

I will head over this afternoon to do this. I'll keep you posted.

 

[NOSIRRAH]

Ok, new information.
From cold, overflow cap removed, idle until the thermostat opens, replace cap.
Dash temperature gauge rises quick and high to 125c (257f), the gauge rises and falls depending on driving or accelerating hard.
No heat coming out of the heater inside the car.
Both fans running, no obvious engine overheating symptoms like knocking or boiling overflow bottle.

 

[crazypirate]

Did you bleed it with the screw on thermostat housing? Nice steady flow?

"Over flow" cap removed does nothing to remove air trapped under thermostat.

On a stock car, some where around 220 both fans should be on..(been long time since stock). Using sensor on waterpump.

257 on gauge, it is getting hot, it uses sensor on pass head.

No heat from heater core?..air locked/blocked..how do the two hoses feel for temp.

 

[my95ss]

In my experience you are not bleeding the system. Leave the cap on, get the car up to temp and them open the bleeder valve until cooland streams out consistantly. Then close the valve. It helps tremendoesly to have the front of the car elevated some to help the air excape . I have had my 95 Impala since 1997 and have changed antifreeze more times than I can remember and this method has always worked for me

 

[toonwarrior]

just for anyone not wanting to spill a bit of coolant just get the bleeder valve and connect a hose to it.

coolant bleeder valve

Our Easy to install Coolant Bleeder Valve directly replaces your original Bleeder Screw and make bleeding air out of your cooling system much easier!

www.yourcustomcar.com

 

[NOSIRRAH]

Did you bleed it with the screw on thermostat housing? Nice steady flow?

"Over flow" cap removed does nothing to remove air trapped under thermostat.

On a stock car, some where around 220 both fans should be on..(been long time since stock). Using sensor on waterpump.

257 on gauge, it is getting hot, it uses sensor on pass head.

No heat from heater core?..air locked/blocked..how do the two hoses feel for temp.

The heater hoses were not very hot, I can hold them bare hand.
I bled from the top of the thermostat housing.
top rad hose was flowing and hot but again bare hand not super hot.
this is all after a drive to heat up.

 

[crazypirate]

To my95ss
"I have had my 95 Impala since 1997 and have changed antifreeze more times than I can remember and this method has always worked for me"

Damn, that makes you around my age??
Bought my 96 in 96...short block, crank, and rods are only stock items..Ai aluminum heads, 227 cam, accel superram intake...

You bleed procedure will Definitely work Definitely work...so does my two..cheers!!

 

[jayoldschool]

Thermostat upside down?

 

[95wagon]

Standard thermostat installed instead if correct one ?
Must have the extra disc on the bottom
This

Not this

 

[95wagon]

It wasn't outside in that cold snap without sufficient antifreeze and started was it ?

If so, it might be prudent to pull the water pump front cover and check the drive isn't stripped

 

[crazypirate]

Thermostat upside down?

Don't think it can be installed upside down, but good thought..also would not stop heater core from getting hot.

Definitely getting warm because 2 sensors are saying it is, sounds like no flow.

So
Spline shaft coupler missing on waterpump??

Solid gaskets on waterpump.??

Let me look at mine in the day light tomorrow, there is a bleed hose that runs to the coolant tank over passenger head that we maybe able to see/feel flow.

Guessing no Infrared gun?

There are atleast two different waterpumps, but rotation is the same.

 

[crazypirate]

95wagon, damn good thought o

n wrong thermostat...not sure what would happen with that??

 

[crazypirate]

Water Impeller spinning on shaft?..not installed on aftermarket pump??..None of us ever got a bad rebuilt part...lol.

Got to look in daylight tomorrow.

 

[95wagon]

The water goes around and around in the engine as it warms up like normal.
But when it get to temp the stat opens but the path of least resistance is the still open bypass.
The majority of the coolant will just go around and around because it is easier than going through the rad or heater

 

[crazypirate]

95wagon you could be totally correct, I just have not personally put in the earlier thermostat...But I think in late 1990s, some guys were using earlier low temp thermostat before the correct ones were made...could be wrong..

To OP...car originally just had no interior heat?..(plugged heater cores were common)

Now with a new waterpump, thermostat, and coolant it over heats? Correct??