Honestly, id much rather find that then a motor that was drained and sat on a concrete floof for 25 years.

That all will clean up nice.

Saw that a lot in the 70s with regular oil changes of quaker state and z7 pennsoil. Oldsmobiles were the worst, cylinder head drains would plug. We used to pour 3 gallons of kerosene in them, run them, and change the oil to valvoline or texaco, never a problem after that.

Saw that a lot in the 70s with regular oil changes of quaker state and z7 pennsoil. Oldsmobiles were the worst, cylinder head drains would plug. We used to pour 3 gallons of kerosene in them, run them, and change the oil to valvoline or texaco, never a problem after that.

Ive seen this exact same thing happen to engines even with proper oil changes . The company I used to work at back in the 80s used nothing but Valvoline, And after pulling the valve covers on one truck and I couldn't see the rockers arms,
Ive never used Valvoline since

Kerosene

That sure would LOOSEN IT UP but then it drops into pan THEN blocks the pickup

I wouldn't doubt that some oils would tend to leave more deposits than some others. But my personal experience is that the vehicle's daily operation is much more of an factor.

For instance, I began my Mopar experience by using the engines from retired police cars. Never have I pulled an ex-squad down that had those kind of deposits. And all of them had a ton of miles. But they had spent nearly all of their operational time at full operating temp.

But I have been into many low mileage engines with that kind of sludge. Most of them were primarily driven around town, running errands, stop and go from home to the store and back without the opportunity to fully warm up.

I have read that when oils are slightly heated and then allowed to cool, that the parafins in them tend to separate out and deposit. While getting the oil up to operating temp and kept that way for a sufficient amount of time, keeps the parafins suspended in the oil.

Modern oils resist that better than earlier oils, but sludging is still possible. And then engine design plays a role too. Think the 2.7 from 20 years ago. In other words, there are a lot of factors beyond simply the brand of oil that plays a role in engine deposits.

And although I haven't done it for 40 years or so, we used to flush engines with kerosene. I was actually taught it in auto mechanics class in high school.