Diagnosing volvo cooling fan issues.
Airflow speed through a radiator is a major influence on the heat it loses. Vehicle speed affects this, in rough proportion to the engine effort, thus giving crude self-regulatory feedback. Where an additional volvo cooling fan is driven by the engine, this also tracks engine speed similarly.
Engine-driven fans are often regulated by a viscous-drive clutch from the drivebelt, which slips and reduces the fan speed at low temperatures. This improves fuel efficiency by not wasting power on driving the fan unnecessarily. On modern vehicles, further regulation of cooling rate is provided by either variable speed or cycling radiator fans. Electric fans are controlled by a thermostatic switch or the engine control unit. Electric fans also have the advantage of giving good airflow and cooling at low engine revs or when stationary, such as in slow-moving traffic.
MVS Forum Member stoutlogic says:
Just a quick FYI,
When your check engine light suddenly rears it ugly amber hue and your volvo cooling fan runs constantly when the car is turned on, running and continues to run up to 5 minutes after the car has been shut down you probably have a bad temperature coolant sensor. Common codes are P0116 or P0118. If you live in the US, Autozone does free code reads for CEL’s.
This is the second time within a year I had to replace the sensor. You can get the sensor for $30+/- from FCP Groton, always a good cheap source for parts. The dealer wants twice that amount. My replacement sensor was covered under warrantee (one year).
MVS Forum Member pcschmid added:
I’ve read about the volvo cooling fan continuously running, but what about the volvo cooling fan not running at all. Checked the fuse and it’s OK. I can turn the fan blades and it will run slowly for a few minutes then stop again. So I figured it is not getting a signal. Pulled the Climate Control panel but it does not look like just that switch could be replaced. Is there another switch it might be or do I need to replace the panel.
I am new to the volvo world, used to VW’s, Toyotas and GM’s.
Car is a 1998 S70, non turbo
MVS Forum Member Trilarry says:
Try This, push the terminal out of the volvo cooling fan relay connector. Two cone shaped terminals should appear out of the connector. Then connect the terminals into the relay with out the connector body. If this works it’s just a bad wornout connector that is causing your volvo cooling fan not to work. I had the same problem.
Sometimes the plastic supports in the connector body that holds the terminals in place wear out and it allows the terminals to not have a good connection. (This is from an earlier post a couple of weeks ago) Here is the whole thread: https://www.matthewsvolvosite.com/chat/p … hp?t=11429
For a quick test turn the AC on