Back flush system - never got hot

[My85Chevy]

Hey guys,

I know a cool running truck is ALWAYS better than hot one, but my 85 needle barely moves off the 100 mark.  I back flushed the system through a tee that was installed by the previous owner today.  Even after 10 minutes and the heater on high the water coming from the radiator spout I installed was luke warm at best.  The heat in the cabin is excellent.  Thermostat not opening?  Not sure what direction to go, or if I should do anything at all!

Thanks
Alan

[Irish_Alley]

if you never get hot it might be cause of no thermostat or its stuck open. if the heat in the cab is good then i would be thinking more like a bad gauge or sending unit

[My85Chevy]

if you never get hot it might be cause of no thermostat or its stuck open. if the heat in the cab is good then i would be thinking more like a bad gauge or sending unit

Thanks.  Yes I was thinking if it was stuck open I wouldn't be getting the heat in the cab.  I'm just going to open it up and see what I have in there.  I have a new stat I'll put in regardless.  180 degree.  What sending unit would you be talking about?    I think the gauge is fine, it seemed to agree with the temp of the water coming out... not hot!

[My85Chevy]

if you never get hot it might be cause of no thermostat or its stuck open. if the heat in the cab is good then i would be thinking more like a bad gauge or sending unit

Thanks.  Yes I was thinking if it was stuck open I wouldn't be getting the heat in the cab.  I'm just going to open it up and see what I have in there.  I have a new stat I'll put in regardless.  180 degree.  What sending unit would you be talking about?    I think the gauge is fine, it seemed to agree with the temp of the water coming out... not hot!

Hey forget that, I know now your talking about the temperature sending unit.  It's a 10 buck part so I'm going to go ahead and replace it and the thermostat and see what the result is.  Thank you!

[Irish_Alley]

you can test those parts before you buy new. if you run it for a while can you hold the bottom hose is the temp really different between the top and bottom?

[Irish_Alley]

http://forum.73-87chevytrucks.com/smforum/index.php?topic=29996.0
http://forum.73-87chevytrucks.com/smforum/index.php?topic=25339.0

[My85Chevy]

you can test those parts before you buy new. if you run it for a while can you hold the bottom hose is the temp really different between the top and bottom?

The upper and lower hoses felt exactly the same.   

The heater hoses on this truck look really bad and about to burst.  Plus I would like to get this tee someone put in before me out.    shows a 5/8 inch to engine and a 3/4 inch to radiator.   Can you guys verify two different sized heater hoses?  They sure look the same to me!

Thanks and thanks for the links to the tests!

[bd]

5/8" hose runs from the coolant crossover next to the thermostat into the heater core, 3/4" hose runs from the heater core out to the radiator (or water pump depending on year and configuration).