An expert who has achieved level 2 by getting 100 points
An expert that got 5 achievements.
An expert that has over 500 points.
An expert whose answer got voted for 20 times.
Re: radiator cooling fan
The cooling fan is switched on by the pcm according to the data received from the ect (engine coolant temp.) sensor.When needed the pcm supplies a ground to the fan relay whitch in turn sends power to the fan.Check your relays and fuses.The pcm very rarely goes bad....
- 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.
The powertrain computer turns the fans on through the cooling fan relays, based on information from the coolant temperature sensor. The fans will only come on when the coolant temp. is pretty high-varies by manufacturer, but it is over 200 degrees, some as much as 230 degrees. So the fans will not come on when engine is started, but they should come on before the engine overheats. You should have them checked. Also find out if the temp. gauge sending unit is separate and different from the coolant temperature sensor-on most cars, they are separate, maybe not on yours? Free advice from a shadetree-not worth a lot, eh? lol.
If there isn't actually any coolant dripping out of the engine, or rad, or hoses when it is sitting, either running or not, you most likely have a blown head gasket. The easiest way to check is, when it is cool, remove the radiator cap, and start the engine. If bubbles are constantly rising to the top of the rrad, your head gasket is gone, and i can almost guarantee you that is the problem. Sorry.
My guess is trapped air in the cooling system. If the cooling system was just filled with antifreeze without bleeding the air, it could cause sporadic overheating. It could also be the cooling fan not coming on at high speeds. Next time the temperature rises, turn on the defroster for th front windshield. That should cause the air conditioner to come on, which in turn will turn on the cooling fan. If the temperature drops, I would suspect the cooling fan sensor is faulty.
if you have high miles, 75k or more I would go ahead and have tempature sensor and thermostat it self change. I don't see battery cable would have any bearing to the temperatureguage or cooling process. Both switch work almost the same, at time it work well other time it read or work incorrectly because it a sign of unit becoming faulty. If the temperature sensor is faulty half of the time it well give you incorrect reading however if the temp sensor working properly and the Thermostat is not, you will also get a high temp reading due to the Thermostat is not working properly allowing the hot antifreeze to flow out from the engine to the radiator which cause the hot antifreeze to be remain lock up in the engine block. Thermostat suppose to open and close when it reach its temperature; at the same time I would also replace thermostat switch which operate the cooling fan. all three tend to go bad over times; replacing all three is a great ideas. Thermostat, thermostat switch and temperature sensor.
check your temp switch to see if operating normally or possiable gauge problem (switch controls fan for radiator if out of range can cause fan to come on later and in turn temp gauge will read higher than normal)may be more than one temp switch to control diffrent speeds.
You may have an air pocket in your system which some times happens. One way to get rid of it is to take the upper hose off on the engine side, fill your system with water until it runs out from your engine block, replace the hose, start your car turn you heater on and set to hi keep the radiator cap loose until the temp start to rise then close tight. Once the air pocket had been remover you can drain some of the water from the radiator using the lower drain plug and add antifreeze.
You have air in the cooling system, it needs bleeding, this is best done from the heater hoses. you cannot have a heating or cooling sysem that is not pressurised. no water no heater no demister no temp guage
Hi. Check the bottom of the radiator or on the side, as you also have a temperature-sending switch. The switch must reach a certain temperature before sending a signal on to the fan relay. The switch just screws into the radiator. If you would like to contact me again about this or other problems, feel free to do so. Bill ASE Master Technician