306 cooling fans

I don't know, but if you are getting heat out of the heater you can use that as an emergency radiator. Run it full blast with the windows open, unless you want to simulate Australian weather.

the stoplight sign is if you got WATER IN YOUR DIESEL so drain the water out of your diesel by undoing your drain plug on your filter houseing.the fan will not run at 90c its got to go a little bit higher than that..

It is over 90. The only times I have seen the stop light (other than switch on) are when the brakes have had a problem, or a lack of water in the radiator leading to overheating.

I don't think there is any connection between the water in diesel sensor and the stoplight.

Nah, the stop light is also for over temp. I had a similar problem with the bitron sensor in my Xantia. It would give me an overtemp warning and a stop light even though all was fine.

In the case of the OP I reckon having a look at the thermal switch that controls the fans and or the wiring to the fans. Try putting 12V onto the fan if you can and see if that gets it going. Short out the thermal switch and see what that does.

There was not on my old 306. The sensor was faulty it sometimes came on even thought there was never any water in the filter. The stop light never came on at the same time.

Pete

The STOP lamp is illuminated for a number of reasons one is when you have no cooling.

This site shows an explanation of how the dual fan system works for cooling

I have a 1998 406 1.9TD with air con and had the same problem. This uses a bitrol system to control the 2 fans. The system is switched on by the brown thermostat of the three on the engine. This then switches a changeover relay and 2 other relays to either give slow speed both fans in series or fast both fans in parallel. These relays are located under the badge on the grill.

Sounds as though you have one of your cooling fans not working. At about 80C they should come on in series both working at slow speed. Also if air con is switched on. At 90 C they should both come on at high speed. These are controlled by 3 fan relays sited behind the rad grill under a cover, check here first for dirty contacts or failed relay. The next possibility is a us fan motor, faulty wiring or faulty earth. There are two 40 an fuses in the engine bay that feed the fans one for each.

Car temperature gauges are notoriously bad at providing the correct temperature reading. You can only be sure of the gauge reading if you check the water with a second temperature gauge. The thermostat opens at 83 C. The fans are controlled from an electrical system Both fans operate in series at 96 C (slow) Both fans operate in parallel at 118 C (Fast) To check the fans do both work, with the engine switched on remove the brown plug on the thermostat housing. After a few seconds both fans should come on at high speed. If your engine cools rapidly after reaching 90+ I would not worry. Water in a radiator is pressurised to lower its boiling point. If you have a leak in the cooling system it will affect the cooling system efficiency and lower the boiling point of the coolant.

The stop light indicates a range of faults normally lighting at the same time as another warning. I've never seen an exhaustive list though.

Ours (petrol 306) seems to come on almost as soon as the engine warms up with no other lights, and the temp indicator is sensible for the rest of a 200 miles journey. The fan runs on even after a short journey (e.g. 4 feet today!) even in cold weather, so presumably a dodgy temp sensor/connection to temp sensor (I suspect the latter in our case). Doesn't always mean a serious fault, anyway and often cooling related.

Chris

The same happens on my HDI partner van , it can be running for about one minute and the temperature gauge will, on occasion, go right round into the red which sets off the stop light flashing and a beeper, this lasts for about 20 seconds and then all goes back to normal.

GGJ

Hi Mike, no, I tend to leave the air set on windscreen and low fan, and sometimes (?) have to turn off the aircon as it turns itself on when you start up. Seems to need a regas anyway so I'll get the thermostat checked at the same time in spring.

Chris

Chris

That is the reason your radiator cooling fans are running. When the controls are set to screen, the air con is switched on to provide dry air even though it does not show on the control panel.

This is why > > Chris

The light shows sometimes though - I'm not sure why if it's lying when it's off.

Do you mean that there's no way to have the air set to screen without aircon - that's a stupid waste of fuel.

On the 406 (which sets the aircon and "auto" fan when it's cold) I let it run aircon sometimes for this reason, but I'm not going to use all the time.

Thanks for the tips.

Chris