endrop - for all your online needs

Technical Coolant temp gauge fluctuating

Currently reading:
Technical Coolant temp gauge fluctuating

G

GuyBrush2015

New member
Joined
Aug 1, 2015
Messages
5
Points
1
Hi! I own a 2003 Fiat Punto mk2 1.4 8 valve car.
The cars temp gauge has started fluctuating from the halfway to almost HOT! The fan kicks in and I'm currently not aware what to do. Any help?
 
GuyBrush2015 said:
Hi! I own a 2003 Fiat Punto mk2 1.4 8 valve car.
The cars temp gauge has started fluctuating from the halfway to almost HOT! The fan kicks in and I'm currently not aware what to do. Any help?
Click to expand...

Thermostat could be sticking sometimes. When the fan is on and the top large hose feels much colder than the smaller hose in front of the fan it is probably stuck. The smaller hose goes from the back of the engine to the front and probably has a small mains powered heater on it just by the the front of the engine.

Do not run the car to hot unless you absolutely have to. There is a big risk of damaging the engine.

You can fit a new thermostat as a DIY job taking probably at least 2-3 hours. Plus you need to have an hour or so to flush thru the cooling system and refill. Not a big job for a garage.
 
Last edited:
The upper hose coming from the thermostat was completely empty. What does that mean and how do I flush the system correctly?
 
https://www.fiatforum.com/punto-mk2-2b-guides/347158-coolant-renewal.html

In Finland if you are not changing the thermostat I think it will be easier to flush the engine by disconnecting the smaller diameter hose that has the electric mains power heater on it. The heater can be seen between the radiator fan and the engine. You can then run the water rearwards and the water will reenter the engine under the ECU which is the thing on top of the engine with the two large electric plugs and thick cables. The guide above suggests removing the thermostat housing but if you have that DEFA type water heater you can avoid having to reseal the housing which some people have had to take apart a second time later on to get it to seal properly.
 
Last edited:
I topped up the coolant and everything seems to work as it should be. Didn't flush the system yet. I'm starting to fear that the head gasket has blown as the coolant amount had decreased and I didn't spot any visible leaks in the system. I'm probably going to replace the thermostat as I don't know when it was last replaced and change the coolant at the same time.
 
GuyBrush2015 said:
I topped up the coolant and everything seems to work as it should be. Didn't flush the system yet. I'm starting to fear that the head gasket has blown as the coolant amount had decreased and I didn't spot any visible leaks in the system. I'm probably going to replace the thermostat as I don't know when it was last replaced and change the coolant at the same time.
Click to expand...

if temp gauge stays on middle when car warms up, there is no need to change it
did you bleed it properly? how much did you have to fill in?
 
Temp gauge stays normal. I had to put over 1 liter into the system for it to function properly, I bled the system only by keeping the radiotar cap off and squeezing the hoses. Coolant came out of the cap and now everything is as it should be. When the engine is cold, the level is between the min and max. But what could have caused the fluctuations at the first place, why was the upper hose empty and where did the coolant disappear?
 
Sorry, my bad, I meant over 2 liters. With the upper hose I mean the one from the thermostat to the radiator.
 
flisko said:
what do you mean upper hose? only 1 liter, so that means it was on minimum, that wouldnt cause it to overheat tho
Click to expand...

There is 500ml difference between max and min. Measured that once during one of these threads! :)

If the bleed valves were not opened air is likely to remain and more water is needed to fill it.

If no air is present then he would be about one liter under minimum before adding water.
 
Last edited:
Me again, roughly 6 months since I had that "coolant disappearing problem". Glad to say the car is still running fine. It needs weekly top ups of about 200-300ml of water to bring the coolant level back up to max.

I had a similar problem as you, one fine day the temp gauge started going up from the middle mark. Turns out to be too little coolant, adding in water got everything back to normal for about 2 weeks before the coolant level dropped again.

Till now I have no idea what is causing the problem, lol. No visible leaks from any pipes. Sometimes I wonder if it's the pressure cap that's gone weak and allowing vapour to escape.

Edit: I also check my oil cap every now and then, no white mayo on it. So doubt it's any head gasket issue.
 
Last edited:
with cars of this age, a very slight leak in the radiator can lose a tiny amount ALL THE TIME,
because of the rad's design it will just steam the water away..so you don't see it, :eek:

we had that on a 2004 16V, in the family
boiled over in traffic, I was convinced it was HG , but a garage decided to change the rad, and it was cured..,(y)
at least they didn't put "radweld" in it..:yuck:

Charlie
 
flashbang said:
Me again, roughly 6 months since I had that "coolant disappearing problem". Glad to say the car is still running fine. It needs weekly top ups of about 200-300ml of water to bring the coolant level back up to max.

I had a similar problem as you, one fine day the temp gauge started going up from the middle mark. Turns out to be too little coolant, adding in water got everything back to normal for about 2 weeks before the coolant level dropped again.

Till now I have no idea what is causing the problem, lol. No visible leaks from any pipes. Sometimes I wonder if it's the pressure cap that's gone weak and allowing vapour to escape.

Edit: I also check my oil cap every now and then, no white mayo on it. So doubt it's any head gasket issue.
Click to expand...

If you are weekly putting in 200-300ml of water then you should be topping up with an antifreeze mixture instead of just straight water. Without the antifreeze, corrosion can be a big problem.
 
I only have 7 months more before this car's gotta go to the scrapyard. I'll probably cross my fingers instead. Maybe I'll add in a couple of caps of redline water wetter next week. I didn't want to add it in consistently as it might be water vapour escaping and that would make the leftover mixture more concentrated as time goes by.
 
flashbang said:
I only have 7 months more before this car's gotta go to the scrapyard. I'll probably cross my fingers instead. Maybe I'll add in a couple of caps of redline water wetter next week. I didn't want to add it in consistently as it might be water vapour escaping and that would make the leftover mixture more concentrated as time goes by.
Click to expand...


magic potions fixes aint the way forward my friend
It'll probably start overheating very shortly after as it gums up the radiator and the water pump and stat

Ziggy
 
You must log in or register to reply here.

Similar threads

M
Technical Coolant temp sensor
Replies
8
Views
993
Mike1alike
Mike1alike
M
Technical Fuel gauge problem.
Replies
3
Views
983
judderbar
J
T
Technical Oil in coolant with check engine light
Replies
3
Views
867
bugsymike
B
F
Technical Coolant temperature sensor replacement?!
Replies
13
Views
2K
Mike1alike
Mike1alike
Bracun
General I need help with the installation of custom gauges - Fiat Punto Mk2a
Replies
1
Views
533
deafmazter
D
Back
Top