'99 Ram 1500
Complaint was no heat. The hottest the truck would get on a test drive was 181, but mostly sat in the high 170s.
{snip}
The jury's out on this repair....I had good heat for half of my test drive then lost it. Re-started later and heat is back (blend door is cable actuated in '99). So I'm thinking maybe still an air pocket somewhere. Seems to me a clog in the heater core wouldn't so quickly come and go??
Quoting myself.....the day after the initial test drive it took some more coolant, maybe a quart or so. I told myself maybe that would help take care of a theoretical air pocket in the very high heater core, but no.
Results were exactly the same: decent heat once warmed up, decent heat 1/2 mile down my private road, but after 3-4 minutes on the highway it would go cold. Once it did this the heat would not return at any speed or idle, UNLESS I shut it off for several minutes and restarted, at which point everything repeats.
Radiator is blocked by cardboard (the owner did this) and cooling system is staying around 192 thanks to a new thermostat.
When heat would vanish the HC input hose was hot, outlet was barely warm to the touch. Thus I was certain I had an air pocket or restricted HC. I pulled the return hose at the wp and the flow seemed low, although I never found time to pull the HC supply to contrast.
SOOOOO, I pulled both hoses again. I flushed the HC with CLR (which, apparently, isn't good for Al or brass but I still left it in there for 10-15 minutes) and then with soapy water numerous times,, then with clean water numerous times.
So far, success! I was able to complete a reasonable test drive with good heat for the entire time. I know the cooling system still has a lot of Stop Leak hiding, so the HC may yet clog up again at which point I'm going to tell her the best bet is a new rad, new HC, and flush the block again
I did watch a YT vid about a product called Thoro Flush which is allegedly superior to the run of the mill rad flushes.
@Kennedy01
