Overheating

So does the radiator fan come on before it starts to overheat? Or does the radiator fan come on at all?

Well it has a new relay, but I also can straight wire it with a wire. so yes they do come on before it overheats. The top hose does build up pressure on it but the new pressure release radiator cap is cold when there is pressure on the hose.

Drove the car to the auto parts store which is less than two miles. Did not overheat on the way but on the way back it overheated and when I pulled into driveway, turned the car off you could smell antifreeze.

Unplug the coolant temperature sensor with the car running, does the radiator fan come on? If so the radiator fan circuit is working correctly and you probably have a bad coolant temperature sensor not reading the correct temperature.

I already bought the sensor so I am going to just replace it now and I bought new coolant air bleeders so I know no air is leaking pass those and getting into the coolant system.

Everything is new on the car. Still over heating. Help!

When you refilled the cooling system you had the air bleeder open until you got a steady stream out of the bleeder screw then closed the bleeder screw? Also, you already replaced coolant temperature sensor? Also, with it running while unplugging the coolant temperature sensor the radiator fan turns on?

Yes, we bled until it was a stream. Yes replaced the coolant temperature sensor. The old one was broken. The one bleeder over the water pump puts out water but the one at the thermostat housing is only letting steam out no water now.

Then there is air somewhere in the system you showing mess with the bleeders when it is hot.

Well you have to mess with them when it is hot to make sure you get all the air out.

There only meant to opened when cold otherwise you can get sprayed with hot coolant. Like I said the bleeder is opened when your adding coolant not while your warming the engine up. Or while the engine is cold you can see if you get air out then.

Did that. Even after the car got warm air was still coming out.

Sounds like there is air in the cooling system that will make a car overheat really quick.

So I need to keep bleeding it after it cools down again and keep adding fluids?

Yes, that is correct those air pockets can be tricky sometimes.

Husband is test driving it again since we got water flow out of both bleeders.

Okay, keep me posted.

Okay, as long as the car is moving it does not try to overheat. Anyway the temperature gauge inside the car is going out? No pressure on any hose like before and when I released the pressure on the radiator cap there was none.

Okay we took the car back out. No heat at all. Anyway, if I do a engine block flush and a radiator flush to get anything that can block a hose out would that help? I do believe there is still air in the coolant system but I am tired of bleeding the system without getting anywhere.

Sounds like the temperature gauge is working if it is showing it is overheating. When the engine reaches normal operating temperature is both the upper and lower radiator hoses getting too hot to hold? Also, are both heater hoses at the firewall getting too hot to hold at operating temperature? I would like to know what temperature the radiator fan is coming on? Because when someone tells me it does not overheat while driving but overheats when i am not driving. First thing I suspect is the radiator fan is not working correctly. Also, you never answered my question of does the radiator fan come on when you unplug the coolant temperature sensor when it is running? Unless someone put some radiator stop leak in the cooling system I would not suspect things being clogged up.

I think we have been bleeding it wrong. It has two bleeder screws. How do you bleed it correctly? Water pump was rusted when we replaced it.

Here is what I have about filling the cooling system after draining it:

We are bleeding the coolant system and it seems like we are getting less air out of the bleeder and more coolant but we will see if this fixes it.

Keep us posted.

We were bleeding the cooling system wrong and putting air through the system still. It is fixed now after spending a bunch of money, but hey the whole cooling system is brand new now.

The good and bad glad to hear you got it all fixed thanks for using 2carpros

Bad news the car ran for a couple of hours before it started over heating again. Air is some how getting into the coolant system. Also no leaks so will bar's leak coolant system repair work?

No I would never use that leak stop stuff it causes more problems then solutions.So are both the upper and lower radiator hoses getting too hot to hold?

They do get hot and have a lot of pressure on them. As of right now the cooling fans are bypassed so they come on when we start the car up. We have put a wire in place of the relay

Why did you bypass the cooling fan relays?

When we had the head gaskets fixed before the relay had gone out. We bought a new relay but misplaced it so we have it to where it come on when we put the wire in its place.

That's crazy to do it that way.i know you got the head gaskets replaced but have you rechecked it with a chemical block tester to make sure there isn't exhaust gasses going into cooling system?

There is air somehow getting in the system. We can bleed the system and after a couple of hours there is air again in the system. I have to be missing something but the whole cooling system is brand new

Exhaust gasses would put air into the cooling system hot air also.

Anyway we aren't getting all the air out thru the bleeders? I don't know what else it could be. The Buick dealerships don't even know what it could be. They can tell everything is brand new and we have all the receipts for everything.

There is one other thing you can use but it requires a air compressor it's called a air lift I use it all the time.you drain the coolant out and you use compressed air to pull all the air out of the system and it creates a vacuum.you use the vacuum to fill the cooling system air free.But that's strange that it runs without heating for a few hours then you suddenly have air again.

Okay next question. Could the heater control valve be bad? We have cold air when in idle or not on the gas which is when I see the car go to overheating but as soon as we accelerate we get heat back? I am even thinking maybe the idle air control valve.

That or a partial clogged heater core which I have seen those symptoms happen.

Heater core brand new. Me and another girl replaced it just two days ago.

Are sure that car has a heater control valve?I didn't see one in my online repair manaul or for sale as a part.