Review on Genuine GM (12378255) Fluid 3634621 Cooling System Seal Tablet - Pack of 5: Effectively Stops Leaks, 4 Grams per Tablet by Robert Johnson

I think they work but only time will tell. I've only driven it 100km. I have a Tahoe 04 with a 5.3 engine. It says 230000. I replaced the water pump last year and after a few months I noticed a coolant leak. Never had to add coolant before the water pump. I can't find a leak anywhere unless it resolves somewhere. Or the water pump is defective. Bought the cheapest autozone. I also change the oil every 3,000km. I'll do anything for this Tahoe. I'm really OCD. Well, after adding coolant for about 6 months, I changed my oil the other day and was doing it when I woke up. The car didn't start. It barely ran out of the drain hole and started pouring out in black chunks. So I hope the coolant didn't get into the oil. I have 862 heads, not sure if they are castek or not. Well I put all 5 on, like I said I've driven 100 miles. I haven't noticed any losses yet. Also, before changing the dirty oil, I poured Castrol oil. Well, before the change before the scrap, I switched to Mobil 1. It never uses oil between changes and doesn't leak anywhere. I was hoping Mobil 1 was just cleaning up. So after adding the sea foam I immediately drained it and cleaned as best I could. I will do another oil change in 1000 miles to see if it gets better. I'll update in a month or so to make sure it worked. Update 8/31/20 It's been about 2 or 3 weeks since I've added them and I still haven't had to add a drop of coolant. I marked my bottle and it didn't move. This is madness. My oil looks better. It's amazing so far. Will update again. Another update 8/2/20. My mom called me and said her antifreeze leaked. I went to check it out and figured I should just change their water pump. 2004 altima 2.5 by the way. Well, it was her radiator. I put 2 of these in as they worked so well on my Tahoe. We let the car idle and before I left we didn't see it dripping again. I'll update again in a few days and see how it worked on her computer.