Tips for those of you that wanted to install an electric fan

[R1190]

Some tips for people that are thinking about installing an electric fan, specially for those of you living in the EU area.

1. Electric fan from an old Peugeot 505 gas fits perfectly in our cars. The retrofitted car is a Turbo from 1974.

2. Thermo switch FAE P/N 37340, 88/79ºC (190/175F), 22x1,5 thread, from a Peugeot 205 MY83/87 works fine.

3. Thermo switch can be installed by your local radiator specialist for some $$. I have installed it close to the lower hose of the radiator.

4. Wiring diagram available at Electric Fan Wiring is very useful. Thanks to the author.

5. Fan relay can be easily installed next to the other relays.

6. How to fix the fan to the radiator? Easy and cheap: nylon strap + washer + foam pad + bottle cap + head of nylon strap can do this job.

7. It is winter time now, so I have to wait till summer season to check that everything works fine.

Regards from Europe, Pepe de la Parte.

[Guest Anonymous]

Coool writeup. does anybody know the part number for the Bosch relays that already have the diode. Would be good info to add to this thread.

[M3M3]

good write up.

i have done many circut installs like this, never saw any need for a diode.

[allbim]

good write up.

i have done many circut installs like this, never saw any need for a diode.

When the thermal switch opens, the magnetic field collapsing in the relay coil generates a voltage that is much higher than the 12 volt supply. Just like an ignition coil. This would not matter if the relay were turned of and on with a regular switch. However, when a thermal switch opens, the contact gap is small enough for this voltage to cause considerable arcing. The diode suppresses (shorts) that voltage and thereby extends the life of the thermal switch.

[R1190]

Coool writeup. does anybody know the part number for the Bosch relays that already have the diode. Would be good info to add to this thread.

A relay with an integrated diode would be the best option, but do not waste too much time searching for it. It is relatively easy to jump a diode between terminals 85/86 of a standard relay. That is what I have done.

Regards, Pepe.

[Guest Anonymous]

Diode is great. As to where to locate the thermal switch as i see it you put it next to the radiator return. That is the coolest point in the coolant system. Putting the switch on the coolant return right as it exits the head would be the hottest point and a better indication of the heat load your engine is putting out.

have fun

[hrg88]

As to where to locate the thermal switch as i see it you put it next to the radiator return. That is the coolest point in the coolant system. Putting the switch on the coolant return right as it exits the head would be the hottest point and a better indication of the heat load your engine is putting out.

have fun

You should put the thermoswitch where it goes on the car it is from, most manufacturers use the bottom of the radiator. If you use the top for a sensor made for the bottom, the fan will come on too soon. The reason most use the bottom is because that is how you tell if the airflow through the radiator needs a boost. Driving on the highway, no fan is needed (already have more airflow than the fan can give) but the top mounted sensor will turn the fan on anyway based on engine temperature. Mounted in the radiator outlet will cause the fan to come on when airflow is insufficient.

I use a 185 deg F switch from Spaal in the lower hose. This switch also does not require a relay, it drives the fan directly. On the track or the highway, the fan does not come on. My sender for the water temp is in the engine outlet and has not shown over 190.

[jimk]

Those looking for a relay with diode Siemens V23154-C52-X90, BMW 12631729004 or 12631711266 found on an E30, engine control relay box (not the one with the clear plastic cover) alongside the fuel pump and main relay.

[R1190]

As to where to locate the thermal switch as i see it you put it next to the radiator return. That is the coolest point in the coolant system. Putting the switch on the coolant return right as it exits the head would be the hottest point and a better indication of the heat load your engine is putting out.

have fun

You should put the thermoswitch where it goes on the car it is from, most manufacturers use the bottom of the radiator. If you use the top for a sensor made for the bottom, the fan will come on too soon. The reason most use the bottom is because that is how you tell if the airflow through the radiator needs a boost. Driving on the highway, no fan is needed (already have more airflow than the fan can give) but the top mounted sensor will turn the fan on anyway based on engine temperature. Mounted in the radiator outlet will cause the fan to come on when airflow is insufficient.

I use a 185 deg F switch from Spaal in the lower hose. This switch also does not require a relay, it drives the fan directly. On the track or the highway, the fan does not come on. My sender for the water temp is in the engine outlet and has not shown over 190.

I have read threads defending to place the thermal switch both at upper hose or at lower hose. I have chosen to install the thermo switch at the lower hose because I wanted to control the temperature of the water entering the engine. That way the thermo switch will detect when the radiator is not providing enough cooling itself and switch on the fan to provide more.

Anyway I do respect opinions that consider the upper hose is the best location. By installing the switch at the upper hose it will detect when the water going out the engine is needing more cooling in the radiator. One thing should be clear: thermo switches for upper and lower locations are not the same. It is important to find the right sensor either for upper or lower location that operates the fan only at low vehicle speeds.

Regards, Pepe.

[M3M3]

LOL, OMG, not another "where is the right place to put the switch" discussion!

put it where ever you want, just make sure the temp the switch turns on is the correct range for that location. no location is better than any other. it is a closed system.

[ozie2012]

Some tips for people that are thinking about installing an electric fan, specially for those of you living in the EU area.

1. Electric fan from an old Peugeot 505 gas fits perfectly in our cars. The retrofitted car is a Turbo from 1974.

2. Thermo switch FAE P/N 37340, 88/79ºC (190/175F), 22x1,5 thread, from a Peugeot 205 MY83/87 works fine.

3. Thermo switch can be installed by your local radiator specialist for some $$. I have installed it close to the lower hose of the radiator.

4. Wiring diagram available at Electric Fan Wiring is very useful. Thanks to the author.

5. Fan relay can be easily installed next to the other relays.

6. How to fix the fan to the radiator? Easy and cheap: nylon strap + washer + foam pad + bottle cap + head of nylon strap can do this job.

7. It is winter time now, so I have to wait till summer season to check that everything works fine.

Regards from Europe, Pepe de la Parte.

since the fan for this peugeot is old, can this mean that the part you need to replace is hard to find. i heard that some Peugeot repair questions are quite tricky in repairs.