Engine Noise Part 2

Use what the mfg recommends. If its been 5 degrees already you probably should have been using 5W30 all along. . It probably has nothing to do with your problem. At 125K its probably over due.

Once put a can of Valve Ease into a small block Chevy that wasn't running quite right. Before the last of the VE was in the engine it started ticking. Had to go get gaskets to adjust the valve train. The VE worked, kept from having to remove the intake manifold but didn't eliminate having to work on the engine entirely. IOW additives might work, might not or result may be unexpected.

Bought a van cheaply with a constant tick and ~120K on it, put another 20K+ on it before rebuilding it. Can't diagnose sounds over the internet though. Your problem seems more dire. Time to have someone more knowledgeable look at it. Check oil on dipstick daily until issue is resolved. If it starts looking milky coolant is getting in the oil and big damage is imminent. It may not be or just be a valve train issue. Good Luck.

I told Dad about it for the first and second time. On the second time, he told me to check the oil because he's seen vehicles make a similar noise when the oil is low. It was full. For the oil being only a month old, it has gotten somewhat brown already although not black yet and is still mostly transparent. Antifreeze in the reservoir is still holding at full or very close to it. I had already switched over to 5W30 earlier in the week *before* it got down to 5 degrees because I looked at the forecast and saw the cold weather coming, so that's when I took it in to change the oil. Also, the valve cover gasket is leaking on this car. We replaced the gasket once as it blew, and then within a month, it blew again. We then siliconed it. A year later, it's leaking again and got past the silicon. It's not leaving any oil on the driveway, but it is on the engine. (The last time it blew it did leave oil on the driveway.)

This is often indicative of a bad PCV valve, GW