Punto (Mk2/2b) Help - overheating

[tenacious dean]

hi guys

i have a problem, my punot 2001 mk2 8v has just failed its mot
reason being that they could not test emissions due to engine overheat. they suggested that it may be a head gasket problem but it has had a new one installed and its been skimed as well as a new thermostat and water pump. the fan has been tested and it does kick in but is intermittent. topped up coolant and bled no probs there also checked oil and no evidence of milk/cream water/oil mixture. Any Ideas?

thanking you kindly

 

[tenacious dean]

just needewd to say that i have small budget and only 9 days to get it back to test center for retest

ty

 

[Ziggy122]

what makes you say its overheating?
The guage saying its at MAX?

Are you getting hot heat out the cabin heater?

I'd be tempted to pressure test the cooling system, since the HG meant new waterpump and stat - i'd be inclined there could be a leak or a blockage somewhere.....

Ziggy

 

[tenacious dean]

had the car ticking over yesterday and it took around ten min for the warning light to come on in the hud then fan kicked in for around 2 min and cut out and temp light stayed on. no leaks in coolant but they did say that there was pressure buildup. also the reason it failed was emissions not tested due to engine overheat.

 

[benny279]

To add to Ziggys comment, I had overheating issues awhile back since I've done a few jobs lately on the car including new thermostat then bled the car so much car was fine after that, but id be inclined to check coolant as well wherever its old or new.

I drained mine yesterday and it was vile and mostly water....(picture attached)

So it now has fresh 5 year oat coolant and 50% distilled water. And car is working perfectly of course i did bleed after that.

So its worth checking these things out, but most importantly....DO NOT drive while its overheating pull over and switch off let cool then continue to drive, dont follow that bye bye headgasket!

Benny

 

[Brendan W]

I would the suspect the thermostst. Start from cold. The top hose should get warm within 5 mins and get warm kinda quickly in one go as the stat opens. The bottom hose should be getting hot within another 5 mins , then the fan should come on after all of that. If the fan is coming on before the bottom hose is good and hot it may be the stat is not opening.

 

[tenacious dean]

thanks for all the advice guys but just to clarify, if I am getting hot air through the cabin heater then does that rule out the possability of a blockage?

 

[benny279]

Are you getting both cold and hot at request without problems?

Benny

 

[s and b]

run the car in your drive for 10 minutes
then with the aid of a towel remove the radiator cap
if you get gushings of pressure and water then you have head gasket failure
report back

remember boiling water hurts so be careful

comprona avertidotiat

 

[tenacious dean]

Yes benny i am getting both hot and cold on demand

 

[tenacious dean]

i also ran it for 10 min and removed the radiator capbut little to no hiss or presaure

 

[tenacious dean]

i monitored the fan all the time and it did not come on at all even thouhh all my pipes were hot

 

[s and b]

i also ran it for 10 min and removed the radiator capbut little to no hiss or presaure

im a little confused here
you say mot station said pressure build up but you dont have any
did it build up pressure because they left it running i guess without keeping an eye on whether it was boiling due to fan not working

anyway to get through the mot why not hard wire the fan so it runs all the time this way it might run a little cool but should pass the mot if engine in good tune
i think you possibly either have a wiring issue a sensor issue controlling the fan or an ecu issue,ideally get fiatecuscan and the appropiate elm lead and you hopefully should be able to plug it into a laptop and check things like actuation of your fan even with the free edition?
also live data

 

[Ziggy122]

yes free MES has the fan actuator test

A blown fuse - dud relay or a damaged wire could be problem, but investigation is required

ziggy

 

[Brendan W]

You say the fan is intermittant. What does that mean?
One way to test the fan is to disconnect the temp sensor with the engine running. The fan should come on and stay on, the red temp lamp lights up and the yellow eml lamp comes on. The fan should not be off with the red lamp on. The fact that you saw the fan shut down with the temp warning still on makes me think the fan is overheating or getting a signal to shut down. When you reconnect the red lamp is off but it will take about three cycles of the motor to get the yellow eml lamp to go off.

 

[stealthtuning]

It sounds to me like one of the coolant temperature sensors are failing, or getting incorrect readings. As far as I know, there are two, but I'm not exactly sure where they are. Mine had no thermostat when I got it, the temp gauge only went up to the quarter way mark, but the other sensor realised it was hot, so kicked the fan in. This confused it and threw up the MIL.

 

[kandilx]

I think it's maybe the fan control relay .