1985 c10 lower radiator hose cold

[TheRealDylan]

1985 c10 with 4.3 v6
My lower radiator hose does not get hot, although the truck does not overheat. I have flushed the coolant, replaced the thermostat, replaced both heater core hoses, and ensured I have flow through the heater core. I am just confused about why the lower hose doesn't get hot while the top does. The top hose I read 150F, and the bottom hose I read 80F. Any help would be appreciated.

 

[edgephoto]

Either your water pump is not moving coolant, not likely since it does not overheat, or your radiator is blocked.

 

[Ricko1966]

150 isn't even operating temperature,so your thermostat isn't open. Probably most of the cooling is being done by the heater core acting as a bypass. Get it up to 200* and see what happens.

 

[77Dmax]

The lower hose should be cold. That's the inlet side after the coolant has been through the radiator. This is a non issue

 

[edgephoto]

150 isn't even operating temperature,so your thermostat isn't open. Probably most of the cooling is being done by the heater core acting as a bypass. Get it up to 200* and see what happens.

Good catch. I read it as 180. Should not have posted just before falling asleep.

When the thermostat does open both hose will feel hot. Of course the lower will be a bit cooler but not ice cold.

 

[TheRealDylan]

Okay I will check tomorrow. I have a 195 thermostat in. I will also have to check again because I believe that when i looked at the temp gauge it read 210, but when using a temp gun on the top hose i would get 150. When I flushed the cooling system, there was alot of rust and overall very dirty. I forgot to mention that the inlet side of the heatercore hose gets hot.

 

[edgephoto]

both heater hoses should be hot regardless if the thermostat is open or not.

I would take the temp. readings with a grain of salt. Those guns are not very accurate when checking temps of non metallic items. I have two of them. One is a Fluke that cost my company a good amount of money and a cheaper one I bought 20 years.

 

[TheRealDylan]

All hoses get hot, but the lower radiator hose. Although I can feel something in the lower hose, I guess older hoses would have a coil/ spring in them to stop them from collapsing, and that may be what I'm feeling... Not sure. I guess this coming weekend I will pull the radiator and see if it's clogged. Would I be able to just pull the radiator and put water through it and see how it flows?