91 2.4 Overheating - skreech
My toyota previa overheats . it is ok sitting idling. When driving it can start to overheat after about 30 minutes or more. Putting the foot down seems to make it overheat quicker , like when driving up a steep hill or mw driving. any ideas anyone. The water level is ok.
91 2.4 Overheating - Peter.N.
If its done a high mileage it could be that thr radiator is clogged. If it only happens when driving slowly in traffic but not at speed, the cooling fan is probably not working.
91 2.4 Overheating - Wurzel83
Sometimes with overheating its best to find the problem using a process of elimination. I would take this approach but there are probably people out there who have more knowledge than me and would be able to offer more precise advice.

I would start with the thermostat because the fact its OK when ideling sounds like the fan and switch are functioning OK. The thermostat cost around £10 (for the part) - do you have a haynes manual? To change is is normally rated 2 spanners for most cars.

Before you change it you could put some radiator cleaner in the coolant and leave it in their for a day.This should loosen off some of the debris within the system. The new anti-freeze costs around £5 so total cost £20.
91 2.4 Overheating - skreech
Thanks guys. i was suspecting a blocked rad. The car has done a lot of miles. has had a new thermostat. so i willl try the cleaner in the coolant.