Thermostat

[gsb104]

hi

i have noticed that my engine gets very hota

fter checking the hoses i noticed the top hose was hot and the bottom hose cold,could this be because of the thermostat.

could this have caused the top plastic part of my radiator to crack

[Mike169]

Hi.

Thermostats tend to fail 'safely' that means they get stuck open but having said that your problem could still well be a faulty thermostat.

Other problems could be an air lock in the system, a blocked radiator, a faulty water pump and the list goes on.

May i suggest you remove the thermostat and see by feel if all of your radiator pipes get hot, the radiator is hot all over ensuring your header tank is full to the correct level at all times.

It could be your engine has a major fault, head gasket i am thinking.

Can you put on your profile more details about your vehicle, the age of the vehicle, the ngine you have fitted, is it diesel or petrol then diagnosis is easier to work out.

Mike.

[gsb104]

hi thanks for your reply

my car is a rav4.2 estate 2.0L vvti with the 1az fe engine

coolant is topped up and is clear with no signs of oil in it

the engine does seem to get very hot but the temperature guage reads normal

gaz

[crofter]

To add to the excellent advice from our metallic amigo a non technical way to test your thermostat is to start your engine from cold and under the bonnet carefully lay your hand on the top of the top hose which should after a while suddenly heat up. with an open (faulty) thermostat the heating up will be gradual.

A normal engine runs more or less at boiling point but it is stopped from boiling by the rad cap causing pressure to build which stops it from actually boiling. That is why you must never ever remove the cap from a hot engine without precautions

Del

[gsb104]

hi

thanks for that i will try that tomorrow