Cheers gents.

 

I've come to whine about my Felicia overheating because of the radiator fan not coming on.

- temp sensor changed ~3000 km ago (also now but that wasn't it chief)

- radiator fan ok (shorted wires, it starts)

- the hoses are warm.

- water pump changed ~4000 km ago with timing belt.

- no white on oil cap

- tank cap only steams when overheated

- temp gauge on dash only barely moves except when overheating, but rad fan worked so didn't mind (odometer gone, I'll change the gauges anyway before anything else)

- guessing it doesn't matter which wire you connect to which terminal of the sensor (since it's just a resistor).

 

I'm most likely going to the fixer's next week anyhow, but it's a pain in the exhaust since the shop moved far out in the damn corn fields. I'd love some pointers to ease my pain.

 

1 hour ago, Blockstar said:

temp sensor changed ~3000 km

 

Do you mean ECU temp sensor or thermoswitch in radiator?

How do you know the engine is overheating ? You say that the temperature gauge is not working properly.

1 hour ago, Papez said:

 

Do you mean ECU temp sensor or thermoswitch in radiator?

 

The thermoswitch on the side of the radiator.

1 hour ago, RicardoM said:

How do you know the engine is overheating ? You say that the temperature gauge is not working properly.

 

I went on a bit of an assumption that the temp gauge doesn't work right since it never hit the mid point recently (never drove too long recently though), but my hint is that the expansion tank cap is bubbling audibly and steaming. The gauge then goes up fast, at which point I switch the engine off, since the fan won't go on. It usually comes on very often and within 10 minutes of starting the car,  

@Blockstar - OK, based on your last, have you tried replacing the pressure cap?

36 minutes ago, KenONeill said:

@Blockstar - OK, based on your last, have you tried replacing the pressure cap?

 

I haven't. It's never given me any grief though. I'm set on not buying parts before I know what the issue is because then I have to take them back  which has happened before. It's basically showing the exact same symptoms of the radiator sensor going, but it's not that.

Could the relay have any part in this, if the fan can be turned on by shorting the wires? Or is that what the sensor actually does?

@Blockstar - Well, so far we've got fan thermo-switch not triggering fan, but fan motor proved good, low gauge temperature, and symptoms of overheating. I honestly think that a failed pressure cap, which reduces the temperature at which the coolant starts to boil, looks like a logical link between all these symptoms.

A stuck closed thermostat could also give fan not triggering and resultant overheating. It would not cause the gauge to misread though. You'd also have a cold radiator.

 

You're correct that the thermo-switch turns the fan on (and off) based on the radiator temperature.

I suspect a partially clogged radiator. I would flush it back and forth with a water hose, then for good measure I would have a look at the thermostat then flush back/forth the rest of the cooling circuit.

15 hours ago, KenONeill said:

@Blockstar - Well, so far we've got fan thermo-switch not triggering fan, but fan motor proved good, low gauge temperature, and symptoms of overheating. I honestly think that a failed pressure cap, which reduces the temperature at which the coolant starts to boil, looks like a logical link between all these symptoms.

A stuck closed thermostat could also give fan not triggering and resultant overheating. It would not cause the gauge to misread though. You'd also have a cold radiator.

 

You're correct that the thermo-switch turns the fan on (and off) based on the radiator temperature.

 

Well the hoses are warm so I don't think it's the stat. If it is the pressure cap, I'm finding a way to send you some beers.

 

7 hours ago, RicardoM said:

I suspect a partially clogged radiator. I would flush it back and forth with a water hose, then for good measure I would have a look at the thermostat then flush back/forth the rest of the cooling circuit.

 

Thanks a bunch gentlemen. When I took the temp sensor (rated 92-97C btw) off the radiator a couple liters gushed out freely, so I'd say the liquid isn't having trouble reaching it. I've had a tiny leak in it before which fixed itself though, so the thing is probably stuffy.

If I have places to drive to I'll short the wires unless that may cause damage, and next week I'll be back with what the mechanic says. 

1 hour ago, Blockstar said:

When I took the temp sensor (rated 92-97C btw) off the radiator a couple liters gushed out freely, so I'd say the liquid isn't having trouble reaching it. I've had a tiny leak in it before which fixed itself though, so the thing is probably stuffy.

Your problem is not a mystery at all. It is either the thermoswitch (but you said you installed a new, proper one) or the temperature of the coolant is not high enough around thermoswitch. The fact that coolant gushed out when you removed the lower (?) hose of the radiator is not proof enough for the proper flow of the coolant through radiator. Reaching it is one thing, flowing around it in proper amount is another.

The overheating in itself is another proof that the radiator is not working properly given you swear for the thermostat.

The coolant reservoir cap hissing is proof it is doing its job, release excessive pressure due to overheating. Nothing wrong with that.

Edited 20 September, 20187 yr by RicardoM

3 hours ago, RicardoM said:

The coolant reservoir cap hissing is proof it is doing its job, release excessive pressure due to overheating. Nothing wrong with that

There I would disagree; the pressure cap is supposed to hold pressure in when the engine is at normal running temperature. Hissing indicates that either the spring or gasket in the cap is weak, or the engine is overheated.

1 hour ago, KenONeill said:

Hissing indicates that either the spring or gasket in the cap is weak, or the engine is overheated.

I was referring exclusively to the latter.

Flush cooling system 
Put a sligtly lower thermoswitch and you are golden

The fixer man said the radiator is busted. He'll install a new one and then we'll see if the head gasket is also cooked. If it is, I'll fix it and sell it for a Poejoe or something, to forget the embarrassment of fixing a car for half its purchase price.

How it can be busted radiator? You said that hoses are warm, which means that coolant flows through it. And if coolant flows through radiator, it must trigger thermoswitch too.

I can think of 2 things which can cause this:

-gas bubble in coolant = faulty HG or low pressure in system

- faulty thermal switch. Some low quality ones can change their parameters. 

Edited 27 September, 20187 yr by Papez

15 hours ago, Papez said:

How it can be busted radiator? You said that hoses are warm, which means that coolant flows through it. And if coolant flows through radiator, it must trigger thermoswitch too.

Not necessarily. An old radiator has a restricted coolant flow. That will not allow enough heat/temperature to trigger the thermoswitch although the output hose might seem to be warm.

Alright, I'm going to retrieve "the red sorrow", as I call it, tomorrow. There was some cable issue. I don't know exactly what but I'll ask for details when I go there.

He swapped out the radiator too, but I'm not mad about that - it had been a little leaky since I bought the car. Also I have a new sensor for the gauge.

 

Thank you all for exhausting the logical realm of possibilities  I'll update tomorrow with where the cable problem was at.

21 hours ago, Blockstar said:

Alright, I'm going to retrieve "the red sorrow", as I call it, tomorrow. There was some cable issue. I don't know exactly what but I'll ask for details when I go there.

He swapped out the radiator too, but I'm not mad about that - it had been a little leaky since I bought the car. Also I have a new sensor for the gauge.

 

Thank you all for exhausting the logical realm of possibilities  I'll update tomorrow with where the cable problem was at.

 

OK, the cable was around where the alarm and central locking modules. I know this because he canceled my central locking when fiddling with the cables looking for the problem .

The module installation (aftermarket from before I had the car) was probably a Romanian job and any minor yanking may have disconnected some elektrix.

 

I said it's fine, some time next month I'll get him a new module because this one's remotes are gone anyhow. I'll have the alarm swapped as well cause it's not working either.

He also changed a wheel bearing, the temp sensor and of course the cooling liquid. 

 

The temp gauge now has the fan kick in at above central position, so I doubt that's working very well, but I'm planning on swapping all the gauges too due to the frozen odometer.

Do y'all think a pre-98 cluster would work properly? I kind of like the font better on that one .