Radiator & hose cold,but Fans are turning on HELP!
CAR Sear Leon, 2007, Petrol Manual
When driving around,
Temp gauge: Stays on 90 (Doesn't increase)
Inside heater works fine, blows out hot air
Hose 1 going from thermostat to the radiator is cold
Hose 2 is hot.
So while hose 2 is cold (thermostat hose) and the front radiator is cold..
the fans at the front of the engine start going on,
after temp reaches 90, but while the radiator is cold!
so the fans are blowing a cold (non heated) radiator)
What does this sound like?
When driving around,
Temp gauge: Stays on 90 (Doesn't increase)
Inside heater works fine, blows out hot air
Hose 1 going from thermostat to the radiator is cold
Hose 2 is hot.
So while hose 2 is cold (thermostat hose) and the front radiator is cold..
the fans at the front of the engine start going on,
after temp reaches 90, but while the radiator is cold!
so the fans are blowing a cold (non heated) radiator)
What does this sound like?
No Unapproved or Personal links in signatures please - FT3
0
Comments
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Replace thermostat0
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+1 thermostat is stuck. What it should be is the top hose from the thermostat to the radiator should be hot, the bottom one cooler or cold. Radiator is cold because the water isn't circulating. Bottom hose is hot because the water isn't circulating so the water lower down is getting hot as well (remember heat rises).
Fans are coming on because the water where the fan thermostatic switch is is far hotter than the water in the cylinder head where the temperature gauge sensor is.0 -
Check the fan switch.
Or... does the car have aircon? Quite often, fans work all the time the aircon's on - to keep air moving over the evaporator, which is mounted with the rad.0 -
"the evaporator," Condensor.:)0
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D'oh. You are, of course, right. The evap is inside the dash.oldagetraveller wrote: »"the evaporator," Condensor.:)0 -
UPDATE: Bleeding done!
(Air con has Not on during the whole time this test has been done)
I Bled the system by this way:
Coolant cap off, tiny air bubbles were coming in the coolant cap visibly, then after reving the accelerator
a huge volcano of coolant came out of the coolant tank and leaked out everywhere, which was a surge of air (perhaps an air pocket was there and escaped right?).
Result?
and both hoses seem hot now (well one a bit cooler than the other, but still warm.
but the radiator still seems to feel cold.
Driving with heater on max!
but one thing is that, when driving around for 30 minutes with the inside heater on maximum hot,
then when stopping the car to feel the hoses then the hose which was originally cold, is still cold, and the other hose hot.
so when driving with the car temperature heater on max hot, that causes that thermostat to stay cold,
1) is that normal? shouldn't both hoses be warm?
with the internal heater on maximum hot?
2) Why if both hoses are hot, would the radiator stay cold?
3) Could it potentially mean more air still in the system ?
Answers to 1) 2) 3) ?? would be appreciated
Thank you.No Unapproved or Personal links in signatures please - FT30 -
1) It isn't normal, both hoses should be warm.
2) The radiator isn't getting hot because of the same reason it wasn't before, the thermostat is jammed shut so coolant isn't circulating through it.
3) Very unlikely given how long you've run it. It'll be the thermostat.0 -
Try turning the heat and interior fan off for a few minutes. Does the radiator get warm? In cold weather the heater may be taking enough heat out of the engine for the thermostat to stay closed.1) is that normal? shouldn't both hoses be warm?
with the internal heater on maximum hot?
It the radiator is cold the cooling fan shouldn't be running. If it is the small amount of heat in the radiator will be quickly cooled.
Is it a diesel? I don't think they heat up as much as petrol cars unless working hard.0 -
Norman_Castle wrote: »Try turning the heat and interior fan off for a few minutes. Does the radiator get warm? In cold weather the heater may be taking enough heat out of the engine for the thermostat to stay closed..
Done this,
yes after turning the inside heat to COLD, and inside fan off then both hoses get hot (well the cold thermostat hose warms up) compared to before.
so I guess the internal heater matrix was taking enough heat, causing the thermostat to stay closed as you suggested.
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otherwise which of these statements is correct?
After driving for 30-40 minutes,
at 30-50mph in this cold weather:
with the inside heater is set to full heat/maximum hot, with blower on full...
a) after 40 minutes, one hose should be boiling hot, and the 2nd hose should be warm (assuming the thermostat has opened) with the fans kicking in eventually?
b) Both hoses boiling hot, the same temperature.
(Thermostat opened), with the fans kicking in eventually?
c) one hose should be boiling hot, and the 2nd one cold, thermostat hasn't opened,
as the car engine gets cool by the blowing cool air, that it is driving through
d) another scenario, regarding the hoses?,
please state what would typically be expected to be 'felt' regarding the hoses ?, temperature, and engine fans ?No Unapproved or Personal links in signatures please - FT30 -
d, 30-50 mph presumably light load on the engine, heater on full. The heater is removing enough heat, no need for the thermostat to open or opening for minimum time sporadically.
If the thermostat is closed both hoses will be cold. The thermostat is normally on the engine.c) one hose should be boiling hot, and the 2nd one cold, thermostat hasn't opened,
as the car engine gets cool by the blowing cool air, that it is driving through0
This discussion has been closed.
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