2000 Volvo S40 overheating

lhackett · Post by **lhackett** » 05 Sep 2010, 13:52

Hi,

I recently purchased a used 2000 Volvo S40 and at about 12 hours into 13 hour drive to Virginia from Michigan, the car started to overheat when stuck in traffic. I turned the air on hot and the engine temperature went down to normal. From what I can hear, it sounds like the fans are working. The car continues to overheat after about 45 minutes of driving. The temperature gauge goes up (not into the red but about 3/4 of the way) and then goes back down to normal. This doesn't happen when moving at fast speeds e.g. on the highway. I had the temperature gauge changed (but to no avail) and have checked the coolant levels multiple times, and it doesn't seem to be leaking coolant. I am scheduled to drive back to Michigan in a couple of weeks but want to have this problem resolved before the long haul. Any ideas? thanks --Lewis

Post by **JDS60R** » 05 Sep 2010, 19:58

S40 cooling relay and controller are well know failure points. Search the site for S40 fan controller or similar. The controller fails and will only turn on fan at last minute instead of starting early and raising fan speed as needed.

https://www.matthewsvolvosite.com/forums ... =8&t=31031

I always replace the thermostat and the pressure cap after an overheat. Statistically they fail very soon afterwards.

lhackett · Post by **lhackett** » 06 Sep 2010, 08:14

Thanks for the response, I will be in touch with my mechanic to talk about addressing this issue. Is it generally a cheap and easy fix (crosses fingers)? Hopefully nothing is wrong with my head gasket. The temperature didn't enter the red so I'm hoping it's OK.