When engine oil turn thick like jello in a diesel can it be fixed?

When engine oil thickens like jelly in a diesel engine, it's typically a sign of contamination, oxidation, or excessive heat. While it can sometimes be resolved by changing the oil and filter and flushing the system, severe cases may lead to engine damage. It's essential to address the underlying issue, such as cooling system problems or using the wrong oil type, to prevent recurrence. Consulting a mechanic is advisable for a proper diagnosis and solution.