Our XC70 seems to overheat after numerous short drives around town. We come back to a parking lot and there is no power to the car. Fob doesn't open power locks. We can get in with the valet key, but the ignition does not accept the key. What has worked is to pop the hood and let the engine cool / and or somehow reset what the car thinks is going on. Eventually power returns and we can drive away. But four mechanic shops, including 3 volvo specialists or dealers can't find any problems. WHAT IS GOING ON WITH THIS CAR?

Over the summer the engine was definitely overheating. Fan would run for 15 minutes after stopping driving. And we were getting overheating warnings. We did get the thermostat and fan module replaced and a new thermostat kit (dealer). The warnings have stopped, but we still have this shut down issue after the short, repetitive trips.

Any similar experiences? Any ideas?

 

sounds like an electronics module, relay or wiring.connector is heating up and the thermal expansion is creating an open circuit which is causing your electronics/electrics to fail. The part cools done and life is good again. I'm surprised a competent shop can't sort this out. Its common for techs working electronics issues to use compressed air or a cold spray to quickly chill a suspect component but they'd need to drive the car/heat it up to the point of failure. When you say overheating, does the car boil over/lose coolant, smell/smoke or does it just indicate a warning light? (which could be just a failed ECT sensor reporting an incorrect temp. That should have been replaced with the thermostat.). My only similar experience was with a failing fuel pump. it would overheat the fuel pump relay and the car would stall. when the relay cooled, the car drove normal. Not saying you have a FPR relay problem but just to parallel how a component can heat up and fail then cool and work normal.