Technical Fiat Punto 2002, 1.2 Active - Overheating

[MechanicImNot]

Hi All,

A couple of weeks ago, our Punto temperature guage started to climb rapidly, with the fan cutting in to cool it down - so MechanicImNot took it to the local garage for them to take a look...

They had a variety of thoughts, including the head gasket - which they tested for, and ruled out - thank goodness!

They worked on the car, and returned it the following days, telling me they had:

1. Replaced the thermostat.
2. Replaced the spark plugs.

Rocking I thought...

However

Where previously, when it was working without problems, the temperature guage never went above 1/4 mark under normal driving circumstances...

... Now it reaches the 1/2 mark in under a mile driving from cold?!? Plus if idling in traffic from more than a couple of minutes, it moves into the red with the fan coming in to cool it down... with the temperature guage behaving like it is pocessed - bouncing between the 1/2 and red region is very short spaces of time?!? :bang:

... the MCU was replaced around 3 years ago

Any help or thoughts on the possible cuases would be greatly appreciated, as I do not want to have the head gasket replaced unless it is certain it will fix the problem.

Many Thanks

Mechanic I'm Not!

 

[J4M35]

Was the engine coolant changed??

 

[MechanicImNot]

Hi J4M35. I believe so, I seem to remember being told they put a shedful of anti-freeze in. Thanks.

 

[Rich_65402]

sounds like theres an airlock in the coolant... its a simple one to fix,

 

[MechanicImNot]

Hi Rich_65402 - Good news hopefully I will take it back to the garage tomorrow. Out of interest where should the temperature needle be normally - 1/4 or 1/2 way? Thanks.

 

[MechanicImNot]

Hi All,

I've dropped my car off at the garage yesterday and had a brief chat with the mechanic, and mentioned a possible air lock in passing and that it may be worth while plugging the car into gizmo to read the MCU...

... to which he replied, I'm not really sure what's going on - I take a look at it tomorrow (today), so we will have to see - watch this space!

I'm praying it is not the head gasket, especially as the intial tests indicate this is not the problem! :worship:

Mechanic I'm Not

 

[JTD_Liam]

Hi Rich_65402 - Good news hopefully I will take it back to the garage tomorrow. Out of interest where should the temperature needle be normally - 1/4 or 1/2 way? Thanks.

The temp gauges on all the Mk2's ive seen have always moved up to 1/2 way and remained there. Never seen a Mk2 only go up to 1/4 and if it goes over 1/2 way theres something wrong.

8v 1.2 engines are renowned for head gaskets tho, so even if it wasnt that to start with, with all the over heating thats gone on, it might be now.

 

[Rich_65402]

The temp gauges on all the Mk2's ive seen have always moved up to 1/2 way and remained there. Never seen a Mk2 only go up to 1/4 and if it goes over 1/2 way theres something wrong.

8v 1.2 engines are renowned for head gaskets tho, so even if it wasnt that to start with, with all the over heating thats gone on, it might be now.

yeah i have to agree, 8v's are a pain in the arse for Head Gaskets specially if its had a history of bad coolant changes, MCU??? btw do you mean an ECU? if the cars overheating an ECU diognostic will not be able to tell you why it is doing that, hes either not a very good mechanic or hes having you on, tbf the simple problem originally sounded like an air lock in the coolant, if the car keeps doing this theres a reason why, theres a couple of tell tale signs if the head gasket is failing or not, first of all when the car is hot, i want you to squeeze the bottom pipe off the radiator and see if its hot or not then squeeze the other pipes slightly higher up if they are cold, you maybe lucky with HG failure, secondly when the car is over heating is the coolant bubbeling in your header/expansion tank??? a sign if the car is truly overheating or not, thirdly, when the temp gauge says its overheating is there any hot air coming out of the vents?? because if there isnt theres still an airlock in the coolant somewhere.. this could be caused by a failing water pump or thermostat is sticking open

ps is there any mayo in the oil cap by mayo i mean a thick white liquid in the oil cap, if there is your coolant and oil are mixing together