Let me know what I need to do to fix this.
Also do these fans automatically turn on every time the car is running, or only if the cooling system isn't working?
My 4.6 is overheating - it runs fine, the gauge stays at 12 O'clock for a few minutes then goes all the way over and pegs after another few minutes.
The fans never turn on.
The coolant is topped off, so that is not the problem.

 

The cooling fans only run as needed - they won't come on until the engine is too hot. They should however come on automatically when the Air Conditioning is turned on. I've seen air in the cooling system cause this, either an air pocket in the system, or something bad like head gaskets leaking (unfortunately common on the northstar)

I don't think though that just the lack of fans would cause a pegged temp gauge, but you never know. If it is only the fans, driving at higher speeds should be enough to cool the radiator and keep the fans off. Does it overheat at speed?

 

I ran the engine today and watched the fans - They did come on, and the temp still pegged.
The temp gauge went to 12 o'clock and after a few minutes slowly crept up until it was on its way to being pegged, so I parked it and shut it down.
So my over heating is 1/ Not the fans 2/ Not the thermostat - I replaced it when it over heated 3/ Not the coolant, as it is full.
Any ideas? Could it be a bad water pump?
Thank you

 

Are the radiator and both radiator hoses getting hot? They should all be Very hot from the sound of it once your engine heats up. If they are getting just as hot as the engine, then your water pump is doing it's job. Same goes for the heater core. Good heat coming from inside?

The water pump is driven off of a separate belt on these engines, on the back of the forward head. You can look to see if the belt is okay and spinning.

If all this looks okay, I think it's time to have a shop look at it. You can actually do more damage to these aluminum engines by letting them overheat. A good shop should have special tool that detects combustion gasses in the coolant - to tell if your head gaskets are the problem. Good luck

 

Thank you for this reply - I will check the water pump belt - hopefully that is the reason. I will also let you know on the hose temps.

 

Thank you VERY much! The belt housing hides the belt but I was able to fish it out. I already ordered the replacement tensioner and belt!

 

Great news. That will certainly cause some overheating. I would recommend turning the water pump pulley by hand before installing the new belt too - in case it is wobbly or seized up.

 

Ok, will do! Thanks again