I just had my A/C fixed on my '87 740T.

Everything went fine except for some leaks in the lines that needed to be repaired.

The system works well especially at highway speeds.

One problem is that the fan on the front of the condenser was seized. I have yet to find a used one. In the mean time I have only run the A/C while driving (I turn it off while idling).

I was told that most Volvo fans are seized when they come into the shop because they very rarely turn on. Is this true?

What can happen if it runs too hot (say in slow traffic on a hot day)?
I was told that the oil will not be be effectively carried to the compressor and it could result in a failed compressor. True ?

What drives the relay to turn the fan on? Pressure? Temp?

How worried should I be about replacing this fan immediately?

Also, how much power (at the wheels) should I expect to lose while running the A/C?

How often does the compressor cycle?

I was recently at the shop having my AC fixed and we watched the high side pressure skyrocket. The fan was not on. With the fan on, the pressure dropped by almost half. Sustained high pressure can cause the compressor to fail. New ones cost about $200 from Hancock Industries in TX. In town, you need the fan. On the highway, there is enough airflow without it, but it won't hurt to run it. In my opinion, the fan should be wired to come on with the AC. You can do this by splicing into the compressor wire and using it as the trigger for a relay that turns the fan on. You may also be able to source a colder fan switch for the radiator. Check the part number on yours and compare it to the specs in the Volvo green books. There were at least two switches, one of which is, in my opinion, too hot. Run a colder engine thermo with the colder fan switch. The cooling system is more efficient if the two match up. If you have a 197, use a 189. If you have a 189, consider a 180. I would not go colder than a 180 engine thermo.

Philip Bradley

If someone finds a cooler radiator switch i would love to get the part number on them.

Hello Daylan:

I'd get the condensor fan fixed ASAP-- I had a condensor failure that was probably the result of overpressure due to inadequate cooling caused by the fan not running. In my case it was because the fan relay needed resoldering. Check to see if your fan runs with a direct application of 12VDC.

Good luck!

Herb Goltz, London, Ontario, Canada '92 245 w/97K mi
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Herb Goltz, London, Ontario, Canada '92 245 w/97K mi

Yes, they're often seized because they never come on, at least in an '87.
The fan is in no way connected to the A/C; it comes on when the radiator temperature is quite high, ~95C. Other years are different.
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Jim McDonald