HDJ81 1HD-FT air intake heater terminal loose

[kenavt]

Seen very little online about the 1HD-FT air intake heater (which I think may only be on EGR-equipped models from looking at Partsouq part diagrams). Mine has a fried lead that I'm replacing, but while doing that, I realized that the terminal's bolt is loose. It feels like it should be snugged up (which is proving harder then it sounds due to the tight space and a bit of slag on the lead inside.

My question for anyone with their 1HD-FT air intake heater installed is - do you have this bolt loose as well? Would that be a useful design in any way, or should it be snugged up?

 

[ikarus]

I disconnected it last year when I installed an intercooler. I don't remember it being loose.

That's the connection for power for the intake heater right? So I would imagine it should be tight or you risk a funky connection.

 

[bigredmachine]

i would get that tightened up or remove the grid heater, the 6.7 cummins have a similar issue and they can drop the bolt into the intake and destroy the motor. the lose connection will cause arcing making the problem worse over time

 

[kenavt]

I disconnected it last year when I installed an intercooler. I don't remember it being loose.

That's the connection for power for the intake heater right? So I would imagine it should be tight or you risk a funky connection.

i would get that tightened up or remove the grid heater, the 6.7 cummins have a similar issue and they can drop the bolt into the intake and destroy the motor. the lose connection will cause arcing making the problem worse over time

Agreed on both of your comments... I have went deep-diving on this air intake heater and bolt terminal, and have a Gordian knot type solution for now, to possibly revisit in the fall. But first I'll recount what I've learned, since I've found very little information about the air intake heater through Googling. There is some info to troubleshoot it and its relay in the 1HD-FT engine factory service manual (RM473e); but I could not find anything about it in the factory service manual wiring diagrams I have (RM184e).

I did learn that the 1HD-FT's air intake heater is the exact same part number as the 1HD-FTE's. That led me to this YouTube video of a fun teardown by a Scot with a fantastic accent, which was a ton of great info.

That said, mine has a different lead shape then most but not all of the ones I saw online (including the YouTube video). I haven't seen any with slag... which makes me suspect this might have been messed with at some point.

I filed off the slag enough to stick some 13mm wrenches in there, and tried tightening (or loosening) it, but it wouldn't give at all. I decided to just let it be for now, and instead to disconnect the relay so that way it can't get any power. It doesn't seem to be able to get any looser (or tighter), so I'm not worried about the pieces breaking apart into the intake, so leaving it be is fine. I would like to get this fixed before it gets cold in the fall though.

Finding the relay, given its not in any of the wiring diagrams I have, was a chore. Turns out it's hidden under the drivers' side (RHD) battery; so pulling the airbox and the battery and battery box was enough. I then popped the black plastic cover off the relay (which was a bit weak in the classic 25-year-old-plastics way), unbolted the right-side lead which I confirmed was for the air intake heater terminal (the other side appears to be 12V unfused so be careful!), and put it all back together.