- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Make sure the reservoir coolant tank is at 'full'. Start the car from cold and observe. After a couple of minutes when the engine has begun to drop in revs ( the coolant temperature sensor should tell the ECU to begin to shorten the injection cycle as the engine warms) the top of the engine and the coolant passage to the thermostat housing should become warm to the touch. When hot the top rubber hose to the radiator should become warm and then hot as coolant begins to circulate. If the top hose fails to get hot at any time then the thermostat is at fault. If you have electrically driven radiator fans these should now come on. If they fail to come an at all you need to check the coolant temperature sensor, the electrical motor fuses and the motor relay. Lastly check the motor itself (just run a 12v supply to it directly). As the ar continues to idle, with the fans running, the bottom return hose from the radiator to engine should also become warm. If the bottom hose fails to become warm this points to circulation problems. Either the radiator had become clogged with rust sludge and needs an extensive flushing out with a high pressure hose or the pump is not functioning as it should. Quickly check that the interior heater works by asking for 'full heat with fan on full'. If the interior heater works this indicates that the main coolant pump is probably OK.
To check the thermostat more thoroughly, remove it from the car and drop it in a pan of near boiling water; the 'stat should pop open. As the pan cools, at 88 degree centigrade or so, the 'stat should pop closed. Failure to observe this tells you the 'stat is a dead and needs to be renewed.
Follow the upper radiator hose from the radiator to the motor. There should be two bolts holding the hose-to-block outlet in place. The thermostat is directly below this in the intake manifold. Before you take it all apart, check your radiator coolant level. If it's really low, there will be no flow of warm coolant to the heater core and you wont' be getting heat in the cab. Fill to the recommended level and recheck your heater...
Are you losing coolant? If not, check for a stuck thermostat. Start the car and allow it to run to temperature. The upper and lower hoses should be hot and firm. If the bottom one is not hot or firm there isn't any coolant flowing through it meaning the coolant is not leaving the motor. The thermostat is under the housing where the top hose goes into the engine. To change it remove the hose and remove the housing where the hose connects. The thermostat pops right out. Install a new one and reconnect everything. If that doesn't solve the problem you'll need to look for other signs of coolant loss including the head gasket, side tanks on radiator, and hose connections.