Lower radiator hose

CAMP.

MEMBER
2005 TOYOTA SEQUOIA
4.7L
V8
2WD
AUTOMATIC
212,000 MILES

Lower radiator hose cold, no matter what I do to the cooling system, the hose it will not warm up or get as hot as the upper radiator hose or the heater core hoses.
Okay. First Let me say I had issues with my radiator cap.
I quickly replaced the cap.
Looked over the cooling system, and everything looked great.
Okay. Started getting cold here in Wisconsin, needed to run car's heater then without warning, the plastic tank on the upper part of my radiator blew out.
Bought a new radiator and thermostat, flushed and filled cooling system.
Using purge and refilling funnel.
Okay.
My truck has dual heater system and the front heater works great but the rear heater blows cool or cold air. My temperature hand never runs hot and it rest between the c an h normal temperature. All hoses hot to the touch but lower radiator hose cold to the touch.
Can someone point me into the right direction, lol. Help.
Oh, water pump not leaking from what I can see and tell but my fan has a slight wobble. Thank you.

1 Reply

CARADIODOC

MECHANIC
33,727 POSTS

You sorry sap. Sorry to hear you're in WI where they throw a pound of salt on an ounce of snow. (I'm here too).

The lower hose should be cold. That means the heat is being given off by the radiator. That assumes the old radiator wasn't blocked. Since the tank cracked, it might be a good idea to check for a leaking cylinder head gasket first. The radiator cap should have relieved any excess pressure, but this seems to be a somewhat common complaint.

At this point if the only problem is the cold rear air, there is likely air in the heater core. Due to the miserable design, we had a lot of trouble burping that air out on '96 and newer Caravans. It will take care of itself over time, then you have to add coolant, but my solution was to use a hose pinch-off pliers on one of the rear heater hoses, then loosen that clamp and pressurize the system. That would push the coolant up and over the top of the heater core, and the air would bleed out by the hose clamp.

If you keep getting air in the cooling system, do the chemical test at the radiator. I suspect you're familiar with that test, but for the benefit of others researching this topic, here's a link to an article that shows what is involved:

https://www.2carpros.com/articles/head-gasket-blown-test