The new fan clutch helped and we thought we’d cured it. That is, until we had the truck out on the first 100-degree day. When we got the truck, stops-leak was holding the cooling system together. So we flushed the system again, even though we flushed it twice before putting the new radiator in, and got some more chunked-up stops-leak out. The three-core copper/brass radiator has smaller cores and is more susceptible to getting plugged (that’s why we flushed the system twice before putting it in). We pulled the radiator, torched off the end cap, and sure enough, it was clogged. Rather than go junkyard again, we sourced this all-aluminum unit from Novak Adapters. They designed it and sell it with the intention of cooling LS-1 V-8s swapped into XJs/MJs, so we knew it would have no problem cooling our “little” engine.