Is there any way to save my truck without a complete rebuild?

[JaketAKACaptainCrasht]

Someone pulled the oil cap off my truck and dumped sugar into it. I didn't know this.

I began to notice a lack of power, and as soon as it began to knock, I parked it and pulled off the valve cover, only to find the sugary mess. I'm thinking about flushing it out real good with diesel. Then I'll fill it with three parts 5w20 high mileage oil mixed with two parts marvel mystery oil, then change the oil like that every day for a week. Could that save it? Or is that engine doomed?

It's a 2.5 4 cylinder in a 1989 S10.

[DR+MrsBearsface]

Hi it would need to stripped down and rebuilt to get out all that mess it is possible to do it but takes hours of work.