Recently installed Used Electric Fan from '83 240 Turbo in front Of my car as an aid to my R-134a conversion.I have wired it according to the Volvo wiring diagram using a headlight relay I bought at Strauss. My Question is as follows: I have a Nissen radiator that I bought from IPD that already has the temp sensor installed that I used as part of the installation.Is this sensor of proper spec for the Volvo fan or should I use a different sensor from Volvo.If I use a Volvo sensor will it fit the radiator ? Are there different types of sensor with differnt temp ranges available ?

If you want the fan to act as an "...aid to my R134a conversion..." it needs to operate when the compressor is running, so trigger it from the comp. clutch wire via a relay. Yes, it would be nice to have the fan cut out when vehicle speed exceeds 45MPH or so, but short of an electronic speed signal and logic circuit*, you'll need a manual switch on the dash to interrupt the clutch-to-relay lead.

UNLESS....you have an M46/OD car. Then you could wire the fan relay's ground terminal by connecting it to the Yellow output wire from your OD relay. This would render the relay inoperative when the OD is on (45mph and up..?). You'd have to put a diode in the circuit to block current backfeed when the OD was on and AC compressor off, but it's not complicated. Disregard all this if you have an automatic - you're out of luck.

Running it only when radiator temp is high will often not help the AC system. The radiator is fairly decent capacity and can keep the engine temp controlled on a warm day in traffic with just the engine-driven fan. But the AC condenser is a weak link in Volvo's AC system, especially if converted to R134a. That's where you need the extra airflow (electric fan).

*(more modern cars with an ECU that controls a LOT of vehicle functions often have this feature)
--
Bob (81-244GL B21F, 83-244DL B23F, 94-944 B230FD; plus grocery-getter Dodge minivan, MGB, and numerous old motorcycles)

Hi. You certainly can use the radiator's temp sensor's switch. But remember, it will work when the coolant gets hot, but not always when your A/C needs the extra airflow, which (you wrote) was the reason for your auxiliary fan installation).
A better way to ensure that the fan always works with the A/C is to tap the wire to the compressor clutch. Attach that to a relay (so the clutch's wire isn't burdened by both the clutch and the relay), and then power the fan through the relay. This way, the fan will go on whenever the A/C cycles on.

How about if I use Thermo switch # 823 959 481 F That activates at 92-87 Centigrade ? This sounds like a better solution as the fan is not necessary when car is going fast & the fan is not needed.Other activate at 94-90C & 102-97C.I do not want the fan operating whem acr is going fast.

use the sw with the rad. i've installed many of them and it's good enough for temp control. good luck, chuck.