Can I swap out an old Chinese diesel heater with the Air 4D?

Updated 09/03/2025 | Published 08/11/2025

Question:

I have one of those generic Chinese heaters already installed. Can I reuse the ducting and wiring if I upgrade to the Air 4D?

asked by: Tyler

Expert Reply:

Maybe some of it, but the 4D heater # AU96MR not plug-and-play. You’ll definitely need to replace:

-All electrical components - Autoterm uses specific control logic

-Fuel pump and hoses

-Possibly the ducting - the Air 4D requires 90mm minimum

Exhaust and intake sizes might also differ. The swap is worth it for reliability, but don’t reuse anything critical. I'd honestly just plan on swapping everything out since this kit includes everything you need. Also some of your old kit might not be as good of quality or could be weathered from use.

What makes you want to reuse the parts? Less install time?

expert reply by: Andrew N

Tyler

9/3/2025

Yeah, mainly just hoping to save time on the install. Do you think keeping the old ducting would cause problems if it’s a smaller size? – Tyler

Andrew N.

9/3/2025

@Tyler I get it, Tyler, reusing ducting sounds like a shortcut, but if it’s under 90mm it’ll choke airflow and make the 4D run hotter than it should. That can shorten the life of the heater. I’d go with the fresh ducting in the kit so you know the system’s breathing right from the start. Are you planning to stick with the same mounting location, or moving the new unit somewhere else in the rig?