I recently installed this 5kw Diesel Heater in my 2004 Dodge Sprinter and although the install went well and it works great now, I did run into some issues. Here is a link to the heater install post.
First, the heater itself was broken when I got it, the plastic tab had broken off the bottom. I contacted the company, and they sent me a brand new one for free (now I have two). Unfortunately, the second one had similar issues, but I overlooked the issue as it would still function correctly.
Secondly, my fan inside the heater made a really loud noise which made it seem like the van was rubbing. Based on this I highly recommend bench testing the heater to make sure it's fine before installing this. All that is required to do this is a 12v battery. This is the sound it was making:
To fix this you could contact the company and I am sure they will fix it. However, I decided to just open it up and see if it was an easy fix, as this was the second one they sent me, and I had spare parts now.
What I found was that there was 4, really cheap, plastic legs that hold the fan in place. One of mine was broken, but upon further inspection that is not what was causing the sound. I simply glued that leg back on and determined that due to the way I was mounting mine (vertically) those legs only serve to keep the cover in place and that would not be an issue.
What I found was making the noise was the fan rubbing on the control board as it was too close. The fan itself was not adjustable.
What I decided to try was to shave off some of the plastic on the tabs where the controller mounted to the heater and move it away from the fan ever so slightly.
This worked and provided enough clearance to prevent the fan from rubbing and still secured the control board.
Something to keep in mind if you go with the cheap Amazon heaters. Bench test them assuming that the standards for manufacturing them are not great.
After this I installed the heater, and it has been working with no issues for a year or so now.