No heat

New owner got some heater questions

04 first gen 3.4L .
It is almost January and I still have no heat . Right now the only thing I’ve done is flush the coolant and heater core assuming that was the problem and when I flushed the coolant and burped the system and then flushed the heater core I had heat for about a day or 2. It looks like I’m getting coolant to and from my heater core and my valve or whatever it’s called for my heat functions properly . I get good blowing ac but my heat doesn’t work , and when the heat is on it blows super weak and isn’t really hot . Someone recommended a thermostat first , I was just about to replace the heater core but not anymore until I verify a problem. The needle sits a little high and it’s making me frustrated. Please help I’m FREEZING

 

A stuck open thermostat wouldn't allow the truck to warm up or atleast it would take forever to get to temp in these now winter temps. A thermostat stuck closed would cause overheating or a quick rise in eng temps. Although I don't believe the thermostat is your issue it doesn't hurt to change it. You flushed the heater core so that's not it. How's the coolant levels when the truck is at operating temp? If levels are good it could also be a failing water pump.

 

Might still have an air pocket in the cooling system. Did you use a spill funnel when you were filling the coolant? Check the coolant level at the radiator cap when the engine is cold in the morning, before starting it

 

When I run the unit at 3k rpm in nuetral I get heat . When I flushed the coolant I was only able to get around just under 2 gallons of coolant and then I flushed again and got a full 2 gallons . I didn’t use a spill funnel I used a regular funnel. Should my first step be getting a new thermostat just for my needle level ? I’m not an automotive mechanic but heat running only at higher rpm’s does sound like a failing water pump but I don’t know.

 

If the coolant level is less than normal the higher rpms help push more hot coolant through the heate core, so the air temp improves slightly coming out the vents.

Definitely recommend a spill funnel kit because it allows you to run the engine for a good bit and watch the air bubbles come out. After a few minutes when the stat opens a pretty sizable bubble should come out. Then remove the funnel and install the rad cap

 

So I’ve always had a good coolant level. And the temp isn’t the only thing that increases with rpm’s, it blows harder. I was thinking of flushing the coolant system again and getting a new heater core just because I don’t believe the coolant has ever been replaced . So I will try that spill funnel . And the coolant system itself just seems really dirty so I am going to try and super flush the system . Along with a new thermostat just for the needle gauge problem.but I want to entertain that water pump idea , could it be failing and only operating properly at higher rpm’s?

 

Is the coolant rusty? Has anyone been adding straight water in the past?

Another member on here had a ton of orange rusty crap in there and he found the water pump impeller blades had rusted away from corrosion. But he had to remove the water pump to see it.

 

It is SUPER rusty in my radiator and my coolant when I flushed it had a crazy amount of chunks of what appeared to be rust. What is the solution?

 

I don't know, you have to look. Remove the water pump and check if the impeller blades are still there, cut the plastic end tanks off the radiator and see if the passages are clogged. If the radiator is corroded and clogged then you know the heater core is too. Running straight water for a long period of time is no bueno

Perform a chemical block test and see if the headgaskets are blown