jabos7

Well, finally success....kinda. I believe I finally got the system topped up, as best as possible for now. With the cap off of the housing I could flex the upper hoses by hand and hear the air come into the cavity below the cap. I probed all around that cavity with a bent wire and still could not find any internal openings, yet the air said otherwise. So I proceeded to fill the area under the cap, about 3 tablespoons at a time, until the level was up into the cap seal area, then "burped" the upper hoses' air into this cavity until the level came down to just air, and then repeated - over a dozen times. I finally reached the point where flexing the hoses only makes the coolant level rise and fall, no bubbles. I'll run it this weekend and see if any air collects back into this cavity, which should be the highest point on the system, and repeat my process again if necessary. Bring me the head of the engineer that dreamed this up.....

this came on my donor engine after mine cratered. During the rebuild I noticed you couldn't see through this thing one way or the other. The passages either cross or turn just far enough in to thwart logic. I'm going to jack it up as suggested, fill as much as I can into the top hose disconnected, then fire it up and see if it pulls down after the thermostat opens. Give me a couple days and I'll let you know what happens. --Any further suggestions are certainly welcome -Jeff 🔨

JohnD - I've done that on a standard radiator cap, but are you saying it should work with this housing/cap? -There's no flow-thru here, despite the appearance of the housing in the picture. Even bone-dry, on the first fill attempts, the coolant would not carry from under this cap onwards into the hoses/radiator. Poppyman--sadly I'm not running any heater hoses, but your suggestion might lead me to attempt that fill where the heater hose would meet the housing. -Hope!

Here's the evil invention. It looks like an open passage would run through, inlet to outlet, but noooooo!

Colin -- that was my first effort, and seemed reasonably successful and messy. But when I see one of the Midget housings with the removable plug/nut it makes me worry that I'm not truly topping up my rig like one could with that opening a the highest point (even though they did have a multitude of problems with dissimilar corrosion around that plug. Pete- I'm good with the airbleed hole, but the odd casting of the upper section seems to keep me from getting coolant even down to the thermostat, let alone filling the block and radiator. There's gotta be a secret I'm missing here......

Spit Greetings to all, and HELP! Can anyone tell me the coolant filling procedure on a 1500 that has the system cap located on the Thermostat housing? First attempts resulted in the coolant mixture instantly filling the space below the cap and spilling back out without moving further into the radiator or engine. I recall on my rebuild as I cleaned and repainted the housing (between the cap and water pump) that I could not figure out the passage paths through the housing. No clear shots visually. How did they even cast these pieces??? I ended up pulling the top hose for a messy fill and slamming in back on, but I know I have some air/room still in the system. Any hints or guidance would be greatly appreciated, and would cool me off in more than one way! Cheers--Jeff/Maryland