My wife's car is a 1997 850 2.5lt. She has been suffering with an ongoing fault with the car, which has gone back to the Volvo dealer four times now, with out the fault being fixed long term. The car is fine when she collects it, but with in 3/4 weeks the fault returns. The problem starts with the engine management light illuminating, and soon after she has trouble starting it. From cold the temperature gauge reads over 50% the cooling fan runs immediately, and the car is very difficult to start. I guess that's due to the high temperature reading which then amends the fuel mixer. In reality the mixture is weaker than it needs to be to start from cold. Has anyone had similar problems or may know where the problem may lie?

 

Coolant temp. sensor? -I can't believe dealer would not find something as simple as that. Maybe, the engine computer module is going?

 

My guess is either the coolant temp sensor or the thermostat.