Got an 85 Ford LTD Country Squire with the 5.0 cfi. Not my first squire nor my first 302, but this sound is a first. It’s all stock, no rigged up junk. When cranked from cold, and left to warm up slowly, a clunk/pop comes from the engine area. The engine doesn’t miss a beat. No smoke, or fluids going crazy. To me it sounds like metal expanding, but to my knowledge I’ve never heard this on a cold engine. I feel silly for asking, as a hot engine cooling down makes racket, but I guess I’m being over protective of this wagon. thanks everyone!!
Take a short length of heater hose, like a couple feet, and use it to see if you can localize the area the noise is coming from. Of course, you put one end to ear, and pull it straight, then aim it to listen under, in front of and on both sides. It goes a long way to localize the area. I'm very familiar with Windsors, but I have to admit, there is always a first. If I had to make educated guesses, I'd say to pull the belts and start the engine, observe the crank damper annulus, and the crank pulleys. Also use the hose to listen around the timing cover, as one thing that comes to mind is an overstretched chain or worn factory cam gear (cast aluminum with Nylon teeth, ugh, not one of Ford's better ideas). Start there, then listen around the exhaust both sides, deteriorating converters can cause backpressure, causing exhaust gases to escape the manifold/pipe joint. Then listen on the backside at the Thermactor crossover manifold and the Thermactor pump and air valves. And finally, lift and properly support the front end, listen around the bottom of the oil pan and the bellhousing inspection cover. Unbolt the cover and manually bar the engine over, listening for scraping, and look for any debris that doesn't belong.
Long time to reply to this……the sound I was hearing……was the valve covers warming up. During this past year of deep work and repairs, tools tapping the valve covers made the exact sound I was hearing. So short answer, nothing was wrong. Just over thinking
