Peugeot 406 coolant temp warning light
My 2001 406 1.8 petrol (Engine 8*6FZ*) has a coolant temp overheating warning and red stop light coming on when engine gets up operating temp. Temp gauge reading 90 degrees and the ambient temp is -15 where I live, Rad fans don't come, but why should they at -15, if I coast down hill warning light goes off. (I will check to see if fans work today only -6) rad felt cool when I opened bonnet when first happened. thanks for any help! Mac
Cars & Trucks - Peugeot - 406
Answers & Comments
1. Check the coolant level if you have not already.
2. The most likely cause is a stuck thermostat so that when the engine is getting up to operating temp the thermostat is not opening at all - or enough - for the coolant to flow freely between the radiator and the engine to cool the heated fluid. If you check the radiator after driving and find it is cold it is a sure sign that the heated coolant that is circulating through the engine at operating temp and higher is not getting to the radiator. The first thing I would do is to change the thermostat and re-check. At the same time completely flush the coolant and replace it with new fluid of the correct spec.
The radiator fans are not going to operate when the fluid in the radiator is cold because the hot fluid cannot flow through from the engine. The fans have a temperature sensor switch.
3. If that does not solve the problem I would suspect the water pump has corroded and needs to be replaced. However from the symptoms you have described I believe a new thermo will fix the problem.
4. Don't drive the car when it is overheating. This is a certain way to blow the head gasket and potentially crack or warp the cylinder head. (In a worst case you can crack the engine block.) It will be nice and expensive to repair if you blow a head gasket or damage the cylinder head.