Radiator Fans Always On & Overheating ?

[Gt_Galant]

Thanks Payaya & PHIL069

i changed the radiator with a spare one i had, and i just try'd it with my radiator thats on my daily car and now both are still overheating but now if i put it in "D" without driving it it slowly go's to "H" and had to turn off the car before it reaches all the way.

So next day i let it idle for a good 45minutes and no pressure in radiator hoses, and fans keep staying on (dunno if it will effect that ?) and temp is at normal, i know once i drive it will go up but didnt drive it as i was doing other things on the car.

also at payaya comment :
"sensors cannot make a car overheat while travelling at speed"

Please i dont mean it in a wrong way or anything like that (you'd know more about engines than me) but my daily when i first brought it i changed everything and did a radiator change, thermostat, radiator hoses, timing belt includes water pump seals etc... gave it the works and was still overheating when travelling at speed and when i got the 2 sensors and changed them, i honestly did not think it will solve it and thought maybe a head-gasket but after the 2 sensor changed i never had a problem with it overheating after that (3yrs now)

And with the radiator fans always on, could it be now a electrical wiring problem ? instead of sensors (cause i changed them twice) maybe a exposed wire or something like that ?

I also just noticed that my heater isnt blowing any hot air would tha effect somethign or is it that the heater core is gone ? i know my coolant leak is fine even with the overheating problem .

[MADFTO]

Anyone, please correct me if you think I'm wrong, I still consider myself as a hack when it comes to car mechanics =P

Hmmmm, looking at symptoms the one that stands out is no pressure.
The fans staying on is just the coolant system thinking the system is too hot and it isn't cooling down because the heat from the engine is being transferred to the coolant but not away from the coolant via radiator.

Reasoning is this, the gauges and ECU take temperature readings from the thermostat that takes the reading from the coolant.

You've stated that there aren't any leaks.
If there's no pressure, then in my judgement it's one of the following:

1. water pump is not working or there's a blockage.
2. the radiator cap not holding pressure
3. there isn't enough fluid in the system for pressure to build (FTO workshop manual states 6.5 litres - Workshop 1 pdf - pg 209 or section 14-2)

Scenario 1 should be eliminated quite easily if you've replaced anything in the cooling system.
For those who aren't so mechanically inclined, the procedure to replace the coolant in a drained system is:
NB: This is taken from the FTO workshop manual - section 14-3 starting from point 8)

8) Slowly pour the engine coolant finto the mouth of the radiator until the radiator is full, and pour also into the reserve tank up to the full line (Quantity: 6.5l)
9) Install the radiator cap securely
10) Start the engine and warm the engine until the thermostat opens
11) After the thermostat opens, race the engine several times, and then stop the engine
12) Cool down the engine. Slowly pour the engine coolant into the mouth of the radiator until the radiator is full, and pour also into the reserve tank up to the FULL line.


The water pump is borked or there's a blockage if you get to step 12, and the coolant is still lapping at the radiator cap.
Scenario 3 will occur if you didn't do the above procedure, not having enough fluid = little to no pressure.


Scenario 2 will result in the reserve bottle being overwhelmed and coolant will start overflowing onto your garage floor, if the system has the correct coolant level.

Adding the symptom that the heater not working sounds like its scenario 3 to me. Not enough coolant in the system means there's too much air in the system for the water pump to circulate the coolant to the heater core. I mean, it could be multiple components breaking down, but Occam's Razor applies to diagnosis (even House rules out the simple stuff first)

Unfortunately, I don't know what you've ruled out and how you've ruled things out so I'm just laying out how I'd diagnose the problem.

[payaya]

Thanks Payaya & PHIL069

i changed the radiator with a spare one i had, and i just try'd it with my radiator thats on my daily car and now both are still overheating but now if i put it in "D" without driving it it slowly go's to "H" and had to turn off the car before it reaches all the way.

So next day i let it idle for a good 45minutes and no pressure in radiator hoses, and fans keep staying on (dunno if it will effect that ?) and temp is at normal, i know once i drive it will go up but didnt drive it as i was doing other things on the car.

also at payaya comment :
"sensors cannot make a car overheat while travelling at speed"

Please i dont mean it in a wrong way or anything like that (you'd know more about engines than me) but my daily when i first brought it i changed everything and did a radiator change, thermostat, radiator hoses, timing belt includes water pump seals etc... gave it the works and was still overheating when travelling at speed and when i got the 2 sensors and changed them, i honestly did not think it will solve it and thought maybe a head-gasket but after the 2 sensor changed i never had a problem with it overheating after that (3yrs now)

And with the radiator fans always on, could it be now a electrical wiring problem ? instead of sensors (cause i changed them twice) maybe a exposed wire or something like that ?

I also just noticed that my heater isnt blowing any hot air would tha effect somethign or is it that the heater core is gone ? i know my coolant leak is fine even with the overheating problem .

When did the fan issue start? Either a sticky relay or the coolant temp sensor to your ECU is fecked.

Heater not working now? Heater works off the heat from your coolant. So again back to my theory coolant isn't circulating right due to a blocked radiator.

Rule out thermostat because you have removed it.
Rule out the fans as they work.
Waterpump could be but it starts to weep coolant from the weep hole weeks before it fails.

Unless that's where the coolant leak is??

[PHIL069]

Blocked radiator or stuffed water pump.

Could be an old radiator hose, if it's lost its structual abilities then the hose could collapse/squeeze together when the coolant attempts to flow though it at pressure, stopping the flow of coolant. Watch your hoses when the engine is operating at temp. Feel your hoses when cool to see if they are over soft or hard and brittle.

Just a reminder

[PHIL069]

How did this end up GT_Galant?