toyota avensis overheating

Got coolant?

Or, is the heater core plugged, or is the valve not opening? The valve should be near the firewall slightly to the left of venter, looking towards the FW.

My guess is the water pump itself has failed. Some cars use plastic impellers on the waterpump, and the impeller blades wear out to the point that water does not pump properly. One of the signs that this is the problem is poor circulation through the Heater.

How many miles/kilometers on the engine? How many miles/kilometers on the timing belt?

It's hard for me to say, the car belongs to the OP. Having said that, a '99 is closing in on 7 years old and the water pump makes sense as a place to start looking ...

It would help to know the stuff you asked about though.

I've never heard of the impeller blades in a Toyota water pump wearing out. A more likely sign of Toyota water pump failure is a leak from the seal. If the water pump is driven by the flat side of the timing belt (I don't know if the Avensis has a timing belt or chain) and the belt is worn or stretched or improperly tensioned, then the water pump may not be driven properly.

Other things to check - coolant condition and level, air in the cooling system, coolant circulation, improper thermostat installation, radiator, faulty coolant temperature sender or gauge, ignition timing, and head gasket.

Actually, I haven't heard of it on a Toyota either, but it is a common problem for water pumps to have. Obviously, it requires a plastic impeller on the pump, and I don't know if the OPs car has this or not.

Head Gasket? Really? His only complaint was that the heater blows cold, wouldn't the head gasket cause other problems that are more important than the heater output?

PS You suggested the water pump is driven by the timing belt, but my guess is you meant to say fan belt (or serpentine belt).

When I list multiple things to check, I list them in order from most likely to least likely, based on my experience. I rarely post SWAGS because they are seldom correct.

From my experience in meeting with customers, I learned that they tend to fixate on a condition that bothers them and ignore other potentially big problems and so they don't provide complete information for a diagnosis.

IMO, the head gasket is the least likely problem for the reasons that you mention - other symptoms, but I'm not discounting the possibility that the OP is missing other symptoms like leaks, steam in the exhaust, milky oil, oily coolant, etc.

I did mean the timing belt. Water pumps are generally not driven by a fan (accessory drive) belt, especially transverse-mounted FWD drivetrains.

Hi bro overheating on avensis are common problem, but they are easy to fix if there is no major damage to the engine. This engine do have terible air lock on them if you do not bleed the cooling system properly.you need to bleed the system propperly first, and make sure that you are geting hot air inside the vehicle befor changing any bit on your engine. if not you can email us to let us know what you have done to the engine. hassan