I want to know their generational symptoms
Welcome to the Forums! Glad to have you. The D model excavators were some of the best Cat made in my opinion. Largest one I owned was a 325DL that was a fantastic machine. Powerful and well balanced. Still have a 321DLCR. Not real familiar with the 336 or 330 enough to give an opinion. The 330DL's were very popular when they were new.
does you cat 325dl has any problem. I used to have 320d it has injection problem
Sold the 325DL many years ago but no we didn't have any issues. 321DL I still have has not had injection issues either.
What kind of injection issues? Wondering if they could be related to dirty or contaminated fuel.
330D and 336D are essentially the same machine. 330D will be older they were later renamed the 336D since the "36" is closer to its actual operating weight. 30 was probably too close to the 329D which is actually a 30 tonner.
That depends on whether you have a machine before 2011 or after 2011. The travel motor before 2011 is a small motor with a convex cover, and the one after 2011 is a large motor with a flat cover. The rotary pump of 336 has an extra breathing tube compared to the rotary pump of 330. These two are quite obvious.
In my country oil is dirty and my cat320d are overload
Before 2011