Again. No heat, all hoses hot, new radiator, new core, both hoses hot.

No heat. No air coming from burping, been burping it for an hour now at 3k rpm. Heat comes slightly warm when at 3000 rpm. New radiator, core, 3 different radiator caps, reverse flushed core about a thousand times, coolant is topped off, and I disconnected the air mix servo and manually actuated the blend door to heat. Went to dealer, they said they think it’s a head gasket but they weren’t sure. I tried a sealer, no more gurgling behind dash and no more endless air bubbles (none at all actually) when burping. Only thing I notice is the hoses go completely flat when cold. Like I said I’ve reverse flushed the core and have a temp gun, both hoses hot. In hose is ~150, out hose is between 130~150 depends on when I measure. I have an UltraGauge truck is running at 194 degrees and has been the whole time. I’m out of ideas and am ready to run this thing into a ditch lol. Anyone have any ideas?

update as I’m writing this. Heat went hot with the front end lifted 6” in the air, but no bubbles have been coming out at all. Temp at vents is 110. When I pull her down off the block heat goes cold.

note: heat goes ice cold within a few minutes of putting radiator cap on regardless of wether or not front is raised.

 

If the hoses go flat when the system cools down that would imply there is air in the system (liquid doesn't compress).

You used a head gasket sealer? These are notorious for clogging up cores, so hopefully you flushed it all out after doing that. Was the heater valve open when you used the sealant?

 

Instead of using that gasket sealer there is a test kit you can buy that will tell you if you have a HG leak. It tests your coolant for combustion byproduct. Also like mentioned above, if the hose goes flat then you have airlocks in the system. If burping doesn't work then you can try to pull a vacuum and refill with the Airlift kits. I've used them extensively and they will pretty much get all of the airlocks out every time. You need a air compressor inorder to use it. A 5 gallon one will work fine.

 

New thermostat? Sorry if I missed it, don't see it in your list.

 

I will definitely try this. I’ll update back on if it works. Thank you!

 

Yeah last year I had it replaced (I had a shop do that cause it was before I got tired of paying labor Lol)

 

Yeah the heater valve has remained open, I’ve flushed it a few times with just water and a hand pump Lol! Both hoses are hot in and out so I don’t think it’s the core being plugged. I haven’t flushed it out yet actually, I have an appointment at a shop to do that (where I’m at in Michigan it’s hard to do flushes yourself because there’s no recycling pickup for civilians, but you can’t just dump it either, and the county/state is no help)

 

So I actually have tried one of those EG test kits and the liquid stayed blue, but I’m not sure if I used it properly or gave it ample time so I’ll try it again today just to be certain. Seems like collapsing hoses indicates air is what I’m hearing? So a good flush, burp, and refill is in order, especially to get all that stuff out of the system. Thanks for all the help so far, I’ve been chasing this no heat situation for almost two full winters now. I’ll post back any updates.