I have this disorder or condition, maybe it would be called in these modern times, "older truck noise detection paranoia disorder"?

Anyway, it got kinda cold so we moved the lever on over to the red and later when I accelerated I started hearing this strange gurgling noise.
For you of the older age group, it almost sounded like a cassette tape on play and you hit fast forward.

Yes or no? I assume it is just hot fluids moving through some heat exchanger, right?

"older truck noise detection paranoia disorder"
OTNDPD: Please donate now to find a cure!!!

 

i thnk you have this disorder.... or maybe im just uninformed.... check your heater core make sure its not clogged or leaking

 

Sounds more like you have air bubles in youre heater line. Since it sits higer up than any other part of the cooling system it holds air. Did you flush the system since you last used the heater?

 

Yes, the coolant was flushed and refilled on 9 nov.
The other day was the first time we used the heat since then.

What should I do?

 

Park it facing uphill and run it with the coolant cap off. This will help purge the system. What you are trying to do is get the fill neck higher than the highest point in youre coolant system. This way it forces the air out.

 

The heater on my 88 does that. I call it more of a swishy swashy type noise.

Anywho, there ain't a damn thing wrong with mine. The heater works great and it doesn't seem to have any effect on anything else. I've drained and refilled the coolant at least a dozen times since I've owned it. I've never had a problem with any trapped air in the system and that sound's never gone away. I don't worry about it in the least.

 

Mine does that too, but it only does it after I shut the engine off (now that I think about it, it could be doing it while running, but there are so many other noises, it all gets mixed together)

sounds kind of like a gurgling noise

oh yeah, kind of off topic, but i'd rather not start another thread:

sometimes, not all the time, I can put my hand up to the defrost vents for the windshield, and the air will be blowing cold (when the heater is on hot) and it's just those vents, everything else is blowing hot as hell, even the little side defrost vents that hit the side windows, I'm pretty sure it isn't supposed to do this, but I've been wrong before

any ideas?

 

Your laminar flow has become turbulent. Happens with old trucks. If its putting out heat and no leaks, rock on.