Flushing problems with Crane toilets

we have a 4 year old mobile home that has 3 toilets and have had nothing but problems with the one at the rear of the home. over the past 4 years, we have had 4 separate plumbers re-seal, re-angle pipes, put heat tape on pipes and snake this thing but the problem continues to persist (lack of flushing/suction power), especially in the winter and have had no other issues with the other toilets, one of which was manufactured on the same date. we have spent $1000.00's of dollars and have now discovered that it was actually the toilet itself...touch wood!!!!! it was manufactured by crane and the following are the imprint #'s. we would like to know if anyone is aware of problems or recalls with this toilet on this manufacture date.

LID...9-742-CR/PL-2 Dec. 18/03
TANK...5437 7-7-12 Dec. 18/03 13-LPF

any input would be greatly appreciated!

toilets

No, and after almost 6 years there is not likely to be one. But I also question whether it is in fact the toilet, but verifying that would require that we be there and actually test the toilet ourselves. I have found that using someone else's diagnosis is usually a good way to make mistakes.