RV Repair: engine heating sys., heater hoses, pace arrow

Question
i have an 1984 pace arrow class a we bought it used in the spring time acouple of years ago. it never heated to good with the engine heaters, it has two one in front for heat and defrost and a rear heated.  ihave had both recored so both are in very good shape now and at this time they still dont heat good they get warm to hot. i think it is the way the heater hoses are ran, the motor is a desiel . the hose comes out of  the motor and "y",s into a hose that goes to both front and back heaters. it was routed to go to the back heater first than for the y . the motor was replaced in the camper and they (who ever put it back in )may have gopt the hoses mixed up. can you shed any light on this i would like to use it in the cold seasons. and yes i did check the heater valve in the hose line

Answer
Hi Karl, I have not seen this in a Fleetwood product that I can remember. You can call Fleetwood and double check me, but I think this is after market. Regardless. I would rerun the hoses with new and take the return from the dash and run it to the rear and back to the engine. What you think? Let me know how it turns out. Good Luck