Technical Cinquencento overheat,fan works only for a short time

[Paulino]

Hi guys.My 899cc cinquencento has started to do something very wierd.
Everything was working ok but the last days it has trouble with keeping it's temperature down.The coolant and the thermostat are relatively new.So I don't think that these are the cause.
The car runs good and after it reaches 90 degree the fan kicks in and stops after 5-10 seconds...that continous until it almost reaches 120 degree.I have
never see it higher. :devil:
I have to mention that when the car is moving ever wery slow i don't have any problem.

 

[Ivan MadGyver]

Hello.
Well it should do that thing but without reaching 120 even stopped,it should just spin longer.
Is the coolant level ok?
Do you run pre mix paraflu coolant or distiled water with coolant percentage by you?
New parts doesn't mean no failure.
We already have 29 degrees temp here,but my 899 doesn't do that (reaching 120) and I changed thermostat on engine and rad one month ago.
A less but possible reason could be large amount of air trapped,in the heatcore I have some,hearing bubbling from time to time when is at 90 degrees but no problem other than that.

 

[Paulino]

I am currently not using paraflu but an other mix from valeo. I didn't have any problems with it at the past.Now air could be a source, my car has air-conditioning so it's system is more complicated. But the heater work fine so probably there is not a lot of air trapped. I am thinking that the problem is related yo the fan...

 

[Ivan MadGyver]

Oh I didn't see you are from Greece too.
Valeo coolant is good,I 'm using Queen,after using both I didn't notice much different in performance,maybe only Valeo has little better cleaning properties (deposites),but I clean the cooling system myself now,so no worries and choose the cheaper of both (although cheaper exist but don't want to push my luck).

Failing fan???I thought a radiator fan would work ok and if problem exists will stay off or rotate slower than normal.

 

[Paulino]

Yes like you, I am living close to Athens. I am planing to replace the thermostat, and i hope that would solve the problem. I will tell you if this was the fault. ?

 

[rallycinq]

Have a feel of the radiator (carefully). If it is hot at one side and cold at the other, it could be silted up.

The other 'known' issue is water pump losing efficiency. Will work fine at any speed above idle, but at low engine speed will not circulate coolant quickly enough.

D

 

[David C]

...the fan kicks in and stops after 5-10 seconds...that continous until it almost reaches 120 degree.

The fan is switched by a basic thermal switch on the rad.
Remove the two connectors on the switch and connect them together to see if the fan runs constantly. The fan is permanently live, so you can do that with the ignition off.

If the fan runs constantly during that test, then it starts to point to the thermal switch or a huge air lock in the rad. Did you bleed it properly after changing the coolant?

Remember, the thermal switch is on the rad and the sensor for the gauge is on the cylinder head, so they are not measuring the same thing.

 

[Ralf S.]

What David said.^^ The fan is shutting off too early by the sound of it.. or there is not enough coolant in the radiator (air lock).

You can try to bleed the radiator. There is a screw in the top corner next to the headlamp. Just unscrew it slowly until air or coolant comes out.

Don't remove it altogether otherwise coolant will spurt out and it's impossible to put the screw back in with coolant going everywhere. Ask me how I know... Just unscrew slowly until it hisses (air) or pisses (coolant). When you see coolant, then it's bled, so tighten it back up.


Ralf S.

 

[Paulino]

Hi guys. I am thinking that the problem is the thermostat, so i will replace it soon. I test the fan and it works ok. I will also replace the switch for the fan... I hope that is not the water pump.. ? witch is more expensive. Now about the air that might be trapped in, from the moment that for the cooling system i used more than 4 litters of coolant i don't think that there is a lot if it even has some...

 

[Ivan MadGyver]

Forgot to ask you,how old is your radiator?

 

[Paulino]

My radiator is almost 1 year old,at least that's what the previous owner told me. But it is in good shape. No fins are bend or broken and i flashed it when i changed the coolant.

 

[David C]

Hi guys. I am thinking that the problem is the thermostat, so i will replace it soon.

Thermostats generally stick open when they fail, causing the engine to run too cold.

Unusual, but not impossible, for them for fail and stick shut.
Besides, if it was stuck shut, the engine wouldn't cool down at all and you say it is fine when you're moving.

 

[Paulino]

Update...
After changing the thermostat and the switch the car at tragic today that was quite hot., max at the 100 mark... Never reached more. Is that the correct temp???

 

[David C]

Update...
After changing the thermostat and the switch the car at tragic today that was quite hot., max at the 100 mark... Never reached more. Is that the correct temp???

90degC is the correct temperature.

 

[Paulino]

Then it's time for a water pump i guess..

 

[David C]

Then it's time for a water pump i guess..

Is the heater hot?
If you put the heater on full HOT and fan on max, does that blow hot and bring the temperature down?

I know it is hot where you are, but the point of trying that is if the heater stays hot and cools the engine, the coolant is getting pumped round the system ok, so the pump is probably ok.

I'd be looking at bleeding the rad again!

The only time mine has run hot is when the rad was failing (not leaking, just fins falling out blocking airflow).

 

[Paulino]

Is the heater hot?
If you put the heater on full HOT and fan on max, does that blow hot and bring the temperature down?

I know it is hot where you are, but the point of trying that is if the heater stays hot and cools the engine, the coolant is getting pumped round the system ok, so the pump is probably ok.

I'd be looking at bleeding the rad again!

The only time mine has run hot is when the rad was failing (not leaking, just fins falling out blocking airflow).

I tried it and after a bit the air turns almost cold. Maybe that's why it didn't have any problems when the car is not at idle. [emoji26] Is it ok if i use it like that for a bit?If i just avoid traffic??

 

[David C]

I tried it and after a bit the air turns almost cold. Maybe that's why it didn't have any problems when the car is not at idle. [emoji26] Is it ok if i use it like that for a bit?If i just avoid traffic??

It does sound like the pump isn't working as well as it should at low rpm, as rallycinq suggested:

The other 'known' issue is water pump losing efficiency. Will work fine at any speed above idle, but at low engine speed will not circulate coolant quickly enough.

If you keep a very close eye on the temperature and avoid sitting at idle for too long, you may be ok. But start hunting for a new pump asap before the real heat of summer hits you.

 

[jackwhoo]

the thermostat starts to open around 90degrees so in free flowing traffic temp gauge should read about 90degrees .


the radiator fan doesn't switch on until around 100degrees .


so in heavy traffic the gauge will get up to around 100degrees or the temperature fan comes on. when the fan runs the temperature drops until fan stops , cycle will then repeat if still in heavy traffic , this is normal.


I have had cars where at idle the flow through the heater is poor especially if the thermostat is open and coolant is flowing through radiator, don't be too concerned about that.

 

[Ralf S.]

Cinq' has either an 82C or 86C thermostat... (i.e. both types were used) so it starts to open at that temperature.

The thermostat is fully open at 90C (actual - the gauge may indicate different) and the fan comes on at 92C... staying on until the temperature reduces to 88C.

The beast should never get to 100C if the thermostat and cooling system is working correctly.

Ralf S.