Technical Temp Gauge Rising and Falling Panda 169 1.2 Dynamic 2006

[torbayron]

On a recent journey of about 120 miles, the cooling temp gauge fell to zero, and engine management light came on. Afrter a couple of miles, the gauge went back up to between 1/4 and 1/2 for a short while, then to zero again. This happened 3 or 4 times during the last 12 or so miles of my journey. The aircon was on, and heater was blowing warm air.
After switching off engine, the fan was still running for slightly longer than normal, and switching on again and restarting did not clear fault.

Ideas? Please.

Thanks in advance

 

[jrkitching]

Ideas? Please.

I'm assuming you keep an eye on the coolant level and that it's normal.

This is most likely caused by the thermostat not closing fully; it's a common failure item. The internal seal perishes and even though the thermostat looks normal and appears OK if you do a boiling water test, it passes coolant even when fully shut.

The cure is to replace the thermostat; fortunately it's simple to do (about 1/2 hr and that's taking my time), and the part can be bought cheaply.

Worth sorting asap because if the engine is running colder than it should, it'll cause excessive wear and trash fuel economy.

 

[torbayron]

Thermostat not closing fully; that's a common failure item. The internal seal perishes and even though the thermostat looks normal and appears OK if you do a boiling water test, it passes coolant even when fully shut.

The cure is to replace the thermostat; fortunately it's simple to do, and the part can be bought cheaply.

Thanks for the prompt reply.
Used my OBD II to diagnose, and it reported a coolant temperature - circuit malfunction CODE P0115.
Cleared fault, Ran the engine with Air-Con, and all seems to be normal. Fan & Temp gauge functioning correctly.
Hopefully just a Panda quirk. (Had a few of those )

Thanks again

 

[jrkitching]

Ran the engine with Air-Con, and all seems to be normal. Fan & Temp gauge functioning correctly.

The first sign of a failing thermostat is the engine won't quite reach normal operating temperature on a cold day (like just now) when lightly loaded (steady 50mph, A/C off). We're talking about the temperature gauge dropping below its usual setting by about the width of the needle.

Ask the engine to deliver a bit more power (like going faster/putting the A/C on) and it comes back to its usual setting.

If you ever notice this, change the thermostat now as it'll get progressively worse as the seal further disintegrates.

 

[torbayron]

The first sign of a failing thermostat is the engine won't quite reach normal operating temperature on a cold day (like just now) when lightly loaded (steady 50mph, A/C off). We're talking about the temperature gauge dropping below its usual setting by about the width of the needle.

Engine definitely reaching normal temps, and remaining steady.
When the fault occurred, the needle dropped to ZERO for a couple of miles then rose to below normal but above 1/4.

 

[torbayron]

Will keep an eye on things and if it recurs, will replace T'stat if neccessary.
Have donated to forum for the help.

 

[The Panda Nut]

Suggest you unplug the temp sensor on the thermostat and plug it in a few times to help clean the terminals. Sounds like a dodgy connection might be involved. JRK's suggestions all good. Just watch that coolant level like a hawk for a while! Thermostats c£30 and only a couple of bolts to fit. Dont fiddle with the quick connector on the bottom or the radiator though if draining the car cut the hose clip off and refit the bottom hose with a jubilee clip,

 

[jrkitching]

Dont fiddle with the quick connector on the bottom

That.

It's a quick connector; it isn't a quick disconnector! If you try to use it as one, it'll likely break, especially on an older car when the plastic has gone brittle.

Just leave the bottom fitting well alone and syphon out the coolant; on models with the expansion tank at the side of the radiator, you'll get just as much out as you would if you disconnected the bottom hose.

If just replacing the 'stat without changing the coolant, you only need to syphon out enough to get the level below the thermostat housing.

 

[torbayron]

Suggest you unplug the temp sensor on the thermostat and plug it in a few times to help clean the terminals. Sounds like a dodgy connection might be involved. JRK's suggestions all good. Just watch that coolant level like a hawk for a while! Thermostats c£30 and only a couple of bolts to fit. Dont fiddle with the quick connector on the bottom or the radiator though if draining the car cut the hose clip off and refit the bottom hose with a jubilee clip,

Thanks for the suggestion. Haven’t tried that but will next time I use the car.

 

[rmjbn1]

+1 on it being a leaky thermostat - I had exactly the same symptoms last winter including temp gauge zeroing and P0115.

Temp gauge should reach 1/2 within a few minutes and not move.

If it sits below 1/2 this indicates it's not getting hot enough.

There's a simple test to make sure - feel the underside of the top radiator hose when starting the car from cold. This hose should stay cold until the 'stat opens. If it starts getting warm within a minute or two then the thermostat is definitely leaking. More info with pics here: https://www.fiatforum.com/threads/common-problem-with-thermostate.465356/#post-4378461

After I changed my thermostat my fuel economy improved immediately - so it'll pay for itself! I wish I'd changed mine much earlier than I did.

 

[varesecrazy]

I had the Gauge drop on my 169 and changed the stat
But it only dropped to 1/4 and no errors

Certainly worth changing the
stat (ALL METAL..)

 

[koalar]

@torbayron car is a 2006


The thermostat will be the earlier simple cheaper type with a seperate coolant temperature sensor on the back of the engine

Do the test mentioned above

Hopefully it's just the stat

Just be careful you order the correct one especially if ordering online