dlstech

I just noticed my lower radiator hose isn't heating up, even after a drive on the freeway. The car runs great and doesn't overheat or anything. I just randomly noticed that when I was bleeding the system for a different issue yesterday.

The hose is completely cool(not even warm) untill about 10 inches away from the thermostat but I think it's only warm there because it's touching the hot heater hose.

The top hose is hot, almost too hot to touch.

Is this normal? Or is my thermostat bad?

seanbev24

It depends what the coolant temp. is. If it isn't getting hot enough to open the thermostat, that's fine. If temp. is above the thermostat temp. rating, it's bad. If you're concerned at all, change it anyway they're cheap.

dlstech

well it's still cold after a freeway drive and then idling for a few minutes I didn't check the exact temp then but when I drive on the freeway my scanner shows 187 or something like that. At idle it's higher probably

Former User

Post a picture of the normal reading of the temp gauge when the engine is fully warmed up. Is it cold where you live?

bigpunn421

i have same problem. my rad fan turned on and my lower hose was still cold on lower part just like yours.....i have a oem honda thermostat im going to swap in tomorow.

ill let you know if my lower hose heats up after.


i have no problems with overheating either. but i can see the thermostat is stuck. the upper hose will be pressurized and the lower feels soft.

dlstech

Ok thanks.

I can't take a picture right now because I'm having another problem with my motor right now and don't want to let it idle for that long.

But the temp needle is exactly parallel to the bottom of the gauge, which makes it a little less than halfway. Is that normal or should it be halfway?

Former User

A typical temp gauge reading at normal engine operating temp is less than halfway, typically about 1/3. If that's what your gauge reads and not higher or unsteady, then I don't see a reason to worry. Our engines normally run a bit on the cool side.

dlstech

Yeah that sounds about right. Thanks for your help.

bigpunn421

how long does it take to warm up usually? at say around 65-70degrees.

my idle is bouncing and i think i have air in my coolant from my throttle body swap.

Former User

5 minutes or so

Bleed the cooling system.

bigpunn421

only way i know how to bleed the system is to let it run with the coolant cap off. but usually before the fan kicks on my car dies from the idle bouncing.

when its cold it idles great. but once it gets warm it tries to drop rpm and just surges. it will do it so bad sometimes it dies if i dont give it gas.

my timing is good, put in a TB with a fitv, new intake, plugs, wires, rotor and cap, and my fan kicks on but the lower hose is still cold.

i am going to swap the t stat and bleed it to see if thats does thr trick. thanks ron. and if you have any thing else it could be lmk

Bendito

Did your oem t-stat fix it? Im having the same problem but my gauge only moves up to the first line (doesn't even pass the "C"). I got a cel code 54 which is water temp sensor. I changed the sensor along with new t-stat & still no fix. Lower radiator hose stays cold & temp gauge reads cold, but heat blows out the vents.

myparkerbros

So I was having this issue, I just did the head gasket myself for the first time. I accidently installed it backwards. car runs and drives fine. but doesnt flow coolant, which is obviously bad for your motor.

Ej2guy28

I am having this exact issue! I bought my car Wednesday with a surging idle and a non working temp guage. I cleaned everything IACV, PCV Valve, even took the throttle body off and unmounted the FITV and cleaned the crap out of it. Re-assembled everything with new gaskets and the surging went away, but now my lower hose and my radiator will not warm up. I noticed block sealent in my radiator when I flushed it. I replaced my thermostat and Coolant temp sensor, still nothing. I guess we are all in the same shoes, I am just going to replace my whole engine with a new heater core and radiator. That should fix the problem!

Black R

Drive it in anger.

Check bottom hose.

Done.

Ej2guy28

LoL, that would work!

sk8member

Bottom hose SHOULDN'T be hot. As that stuff is going into your motor to cool it, the TOP should be hot, as that is the coolant that has just cooled your motor. Hot coolant enters the top, flows through the radiator, out of the bottom, into the engine. It is fine. If it's not broke, don't fix it.