Peugeot 308 stop signal flashing & beeping, warning - temperature too high, often not starting over first time

Car: Peugeot 308
Model Year: 2010
Categories: Running Rough, Starting & Power Loss
This problem has been going on for about 12 months now. First it started with the warning signal "anti pollution system failure" which came & went with not rhyme or reason. Then this message plus fan running on, sometimes for up to 20 minutes after car engine off. Had to have battery replaced as the fan eventually ran the battery down, worked good for a while. Then started again, as it was misfiring again, garage changed spark plugs, coil pack worked well again for a while.
Then anti pollution came back & fan again, took back to garage he did something under the bonnet to the temperature gage with a screw driver & turned on all the heaters & problem went again.
For the last 7 days the problem has got progressively worse, anti pollution came up again, but was running fine, a few days later fan started running on again, but would go off again once engine off. A few days later we now have a car that as soon as you start engine says temperature too high, temp gage goes back and forth between being in red to half way as you drive, then when gets to red stop sign comes up with beep.
Took to garage yesterday as car wouldn't start again & same stop sign coming up, oil was put in as was very low (even though only put in about 6 weeks ago) then he ran the car and said there is either a problem
With the thermostat or sensor. He didn't plug into the diagnostic however the engine management light went off once more oil was added.
He said that if the stop light comes on to pull over let car cool
Down before driving again, but this happens about 1/2 minutes down the road even at low speed.
He said that eventually the engine may power off, which is obviously a scary thing to me to be in a car that may lose power!!!!!
Garage are saying they think replacing the thermostat (which they have quoted £260) will hopefully sort the problem!!!!!! Does this sound right? Has anyone got any other ideas how to fix the problem? Or experienced same thing? This close to Xmas is a nightmare as I don't want to use the car with kids in it incase it powers off & break down again, plus garage can't fit this part until the new year!!!!! Help
Posted: Dec 22, 2015 (9 years ago)
1st thing you need to establish is the actual engine temperature.
or is it a fault in the wiring.
or is it even overheating.
It is possible it is the thermostat but that takes me back to point 1.
My procedure with this would be plug in scan tool to read just exactly "what" temp the computer is "seeing"
while an independent thermometer measures the actual coolant temperature.
If my thermometer corresponds with the scan tool data temp and it is high then the thermostat is the next check.
Reason I'd go about this is French cars have bad wiring and can shot circuit across wires giving the computer crazy readings.
Posted Dec 23, 2015 (8 years ago)
Get the garage to check the connectors into the ecu.Its possible there may be coolant at the ecu.
Posted Jan 1, 2016 (8 years ago)

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