This 87 crew cab dually has a 460 carbureated engine. The thing is giving me heart failure. Started out would overheat. No bubbles in radiator and could see the coolant circulating. Went ahead and changed the thermostat anyway just for good measure. The fan clutch didn't seem to kick in so changed that. Had radiator checked out and cleaned. Runs cool now for first 30 miles or so then slowly starts heating up. (Muffler?) Doesn't have a cat. Also most trucks I've had you could idle to cool down this one you idle will actually heat up. (Just replaced fan clutch) Any ideas greatly appreciated since this thing is causing me to tear my hair out.

 

Ok, so this is weird. I would wonder what kind of shape the coolant was in to begin with. If it was rusty, I would start by looking at the flow through the radiator when hot (cap removed so you can see it). When the thermostat opens, you should see a fairly strong flow. If not, start by taking a look at the waterpump, as the fins could just have rusted away.
Another thing to check is the airflow through the radiator; these had sheilds that helped funnel air to the radiator, and if they're missing that could be a problem.
Make sure that it has the proper fan (there is a difference for with and without A/C), and recheck the clutch to make sure it's working.
Let us know.

 

Going to pull the radiator and have it tested. Brand new fanclutch but, probably made in china. Will check it again.
Thks
Tom

 

Sending radiator to different shp this time. Came back last time looking like it hadn't been touched