Engine Sludge/Carbon Removal

[1987Comanche]

When I picked up the '90 last year she had been neglected and the inside of the engine was nasty. I had the VC and oil pan off the 4.0 and scraped a significant amount of sludge and carbon off everything I could reach. I pulled the pushrods, blocked the pushrod holes and scraped about 2 Coke cans full of carbon off the cylinder head. The timing cover was completely plugged with sludge/carbon and the only free space was where the chain actually moved. The bottom of the block and rods were skunky too.

After scraping what I could and seeing what was inside I figured the best method of non aggressive cleaning was to change the oil more frequently than I normally would. I've been changing oil every 2K miles (2 months) and I recently saw Pennzoil advertised as having extra detergents that remove sludge. Is there any merit to this? I don't want to do anything aggressive like Seafoam because I'm sure there's plenty of carbon waiting to break free and clog passages.

[Northup]

You can use ATF fluid to flush your oil. Use like a 50/50 mix of oil and ATF fluid and oil, run it for a few minutes to get it threw the engine then drain while hot and flush with fresh oil and filter. The detergents in the ATF fluid will do a good job of cleaning. I also have seen and read of people doing flushes with kerosene but thats a little aggressive for me, I like a little gunk to hold my engines together.