2017 Peterbilt 579 Heat not properly working

you think bad waterpump? not putting the correct pressure? the outlet hose is cold inlet hose superhot

 

i did the EAS test all came back good but outlet hose on diagram coming from the valve going downwards is cold the inpet one is super hot

 

If you had a faulty water pump, you’d see that on your temp gauge.

I believe, you just have a water flow problem right in the area you’re messing in.

 

where does the outlet lead to? goins inlet to heatercore and from heatercore to outlet? so maybe not enough pressure for the collant to go thru the heatercore?

 

As the diagram shows, there are restrictors and valves. I’d disassemble everything and see if one of those pieces is plugged. While that’s all apart, I’d put a garden hose to the heater core, just make sure it still flows free and there isn’t fresh debris plugging it, somehow. Put water to it, in both directions.

 

i replaced the heater core about a month ago there was Debrie like gunk plugging one heater outlet and i replaced the heatercore and it worked like a charme for a month then bam.

 

If that gunk plugged the heater core, you can bet those flow restrictors and this new heater core are probably plugged.

You need to find out what the gunk is.

 

it looked like slush like a bit solid pieces

 

It’s hard to say. Could be some sort of stop leak, something degrading, old coolant having never been flushed, I can’t say for sure. There should be a coolant filter, somewhere. It’s probably packed full, too.

 

you are correct i didn't think about the coolant filter