Hi all,

Recently I noticed my 2007 1.2 active grande punto engine temperature seemed to rise and stabilise a lot faster than usual, I then noticed that while driving it drops to just below the half way mark, and then rises and stabilises at the half way point again.

I have had the car from new and done 57000 miles. It has had a water pump/coolant change and timing belt 10000 miles ago and has been a brilliant little car.

Has anyone else experienced anything else like this? All help appreciated.

Cheers

Thermostat stuck open after a while maybe. Cheap and easy fix can't think anything else.

Thanks for the reply, I was leaning towards the thermostat as the one thing it isn't doing is over heating, it's just getting upto temperature rapidly

Rapidly = ?
From a cold start how long does it take ?

I work 7 miles away, it usually hits the correct temperature after about 5-10 mins or 4-5 miles. Recently I am finding less than 5 minutes from cold and after about 2 miles of dual carriageway driving.

My thoughts are thermostat/temp sensor. Or possible water pump issue but that seem unlikely as I would expect the temp to rise past the halfway point if this was the case.

Well I think it's very normal time.

Temperature in my 1.4 engine gets to 88-90C (half mark) in about 3-4 minutes driving and sits there forever. (in summer maybe sooner)

If you see a temperature drop while driving replace thermostat

That's good to hear. Thanks for your help.

It's the little sudden drops that have me concerned so I will monitor it further and if needs be will replace the thermostat.

Appreciate your reply

Double check your oil and coolant as may be to low, it can cause this issue (even a pipe leak, but you'd more likely notice a puddle under car). Could be head gasket at worse case scenario. My partners Peugeot did that with temp up and down, but had oil in coolant. Head gasket on its way out. If head gasket usually not worth doing. As soon has replaced can go again 12 months later (talking from experience there). My 1.4 warms up fast but stays steady in the middle so that's not a concern really. Its the temp going up and down

Quick update

Fitted a new genuine thermostat this morning with the temp sensor in it, and the temp still drops.

Could this be caused by the map sensor I hear is very common? Could it be the map sensors conflicting with the temp switch data and causing it to register hot cooler than it is? It just confuses me out it doesn't over heat only gets to the correct temp and then fluctuates below?

Cheers

Trailpimp uk said:

Quick update



Fitted a new genuine thermostat this morning with the temp sensor in it, and the temp still drops.



Could this be caused by the map sensor I hear is very common? Could it be the map sensors conflicting with the temp switch data and causing it to register hot cooler than it is? It just confuses me out it doesn't over heat only gets to the correct temp and then fluctuates below?



Cheers

Click to expand...

You replaced the whole unit right ? With a new coolant temp sensor?


There is one map sensor (that's acting as AIR temp sensor also) on the intake manifold.

You can check air temperature / coolant values via OBD. ( find the cheapest elm, will do the job )

But I don't think a bad air sensor would cause that problem.