Peugeot 307 - Red Stop light and rising temperature gauge issue - Ash_11

Hi My car is a Peugeot 307 1.4 petrol 2005 model with around 80k miles.

I will be driving steadily along at say 60mph all is well. Then, suddenly, the STOP light flashes and the temperature gauge rises to the red zone, its like that for like a second and then returns back to normal. I then stop the car, there is nothing actually wrong (i.e. not overheating, water fine, oil fine). Turn the ignition off, restart and the car is back to normal.

Then it can happen again, it is really sporadic as to when it happens, it can also happen at low speed too, but definitely no over heating.

The other issue is the heat blower inside the cabin does not provide heat anymore, it is very minimal.

So far I have had the temperature sensors replaced, engine temperature sensor, coolant temperature sensor and a replacement thermostat, none of this has resolve the issue, even my mechanic is puzzled.
Any ideas as what this could be?

thanks in advance for you help.

Edited by Ash_11 on 06/11/2018 at 09:32

Peugeot 307 - Red Stop light and rising temperature gauge issue - hardway

If this came in to me with your explanation I'd be checking the coolant with a dye tester.

Simple tool,

there's a liquid in the tool that reacts to combustion gases in the coolant,

Idiot proof as the liquid changes colour is there's any gas in the coolant.

And a faulty head gasket will also produce gas lock in the coolant so the gauge will briefly shoot up AND the gas will produce a lock in the coolant making the heater matrix work poorly.

Probably not what you wanted but get the coolant gas tested.

If you want they're selling these block testers as they're called on Ebay for around £30.

Very easy to operate.

Peugeot 307 - Red Stop light and rising temperature gauge issue - RT

If this came in to me with your explanation I'd be checking the coolant with a dye tester.

Simple tool,

there's a liquid in the tool that reacts to combustion gases in the coolant,

Idiot proof as the liquid changes colour is there's any gas in the coolant.

And a faulty head gasket will also produce gas lock in the coolant so the gauge will briefly shoot up AND the gas will produce a lock in the coolant making the heater matrix work poorly.

Probably not what you wanted but get the coolant gas tested.

If you want they're selling these block testers as they're called on Ebay for around £30.

Very easy to operate.

Not idiot-proof - it took 18 months of inconclusive tests, including coolant dye, for me to prove my Hyundai's head gasket was failing - a hairline crack allowing coolant to be sucked into the cylinder but not combustion gas to go out -in the end, the gasket failed completely and the engine had to be taken out and rebuilt.

I had something similar on a Vauxhall SOHC engine.

Peugeot 307 - Red Stop light and rising temperature gauge issue - Ash_11

Hi, thanks for your reply, sorry I completely forgot to say, the garage has already ruled out any head gasket related issues, they have done some checks for this, and even when the stop light comes on and the temperature gauge shoots up for those couple of seconds, the garage checked the coolant temperature and it was definitely not overheating and showing a normal temperature reading.

please let me know if you have any suggestions?

do you know if an air lock of some sort may cause this kind of issue?
Thanks

Edited by Ash_11 on 06/11/2018 at 12:28

Peugeot 307 - Red Stop light and rising temperature gauge issue - Andrew-T

... the garage has already ruled out any head gasket related issues, they have done some checks for this,

Don't bank on it. A few years ago I noticed some oil in a coolant reservoir and asked my indie (reliable and knowledgeable) to check the HG and he reported it was OK. When the oil continued to appear I had the head skimmed and the HG renewed - problem solved. The tests aren't always definite.

Peugeot 307 - Red Stop light and rising temperature gauge issue - Gibbo_Wirral

I will be driving steadily along at say 60mph all is well. Then, suddenly, the STOP light flashes and the temperature gauge rises to the red zone, its like that for like a second and then returns back to normal. I then stop the car, there is nothing actually wrong (i.e. not overheating, water fine, oil fine). Turn the ignition off, restart and the car is back to normal.

Both of my previous Mk1 307s had this, and many other 307 owners have too. It IS the coolant temperature sensor.

You say you've had it replaced, but its possible the replacement was duff, or the wiring may be damaged.

Take another look. And also while you're in that part of the car, take out the battery and tray and give the earth points under it a good clean.

And do the same for the cooling fan relays under the plastics. between the engine and the grille.

And also if you've lost coolant when changing it you need to top up using the old pop bottle filler trick, and operate all three bleed screws to get air out of the system.

Edited by Gibbo_Wirral on 06/11/2018 at 12:35

Peugeot 307 - Red Stop light and rising temperature gauge issue - Ash_11

Hi thanks for your reply, I will definitely give that a go,

I have asked the garage again regarding the temperature sensor, and they say the one they have replaced was one that came with the thermostat and they replaced that at the same time, is this a different temp sensor? are the temp sensors easy to change?

I will check the earth points, sorry what is the old pop bottle filler trick, how do I do this? im guessing this is to prevent air getting in.

Is the process for getting the air out the system straightforward, where are the bleed screws located?
thanks

Peugeot 307 - Red Stop light and rising temperature gauge issue - Gibbo_Wirral

Temperature sensors are pretty easy to change.

Take out the battery and its on the side of the engine, held in by a circlip.

Its usually here, item 7:

www.peugeotforums.com/forums/attachments/307-38/22...g

I must say though that I've never heard of the sensor coming in a kit with the thermostat.

More on your problem here where its been a little more than just replacing the sensor:

www.peugeotforums.com/forums/307-38/temperature-to.../

See the "Haynes Hint" at the bottom of this picture for the pop bottle filler:

nwex.co.uk/temp/coolant/coolant2.jpg

Bleed screws covered here:

www.peugeotforums.com/forums/307-38/peugeot-307-co.../

Edited by Gibbo_Wirral on 07/11/2018 at 12:45