Fair play for the effort you are putting into this project. It's valuable to those of us who are interested in working on our vehicles, seeing your detailed step-by-step approach. Wish you are yours a wonderful Christmas and a healthy and prosperous New Year 🙂
I had this issue with my D4 and chased a few items to diagnose. I settled on the heater matrix without fully testing - and it was a mistake! One new matrix fitted (no change), I discovered it to be the diverted/heater control valve mounted behind the webasto unit. £50 Amazon part fitted and it was 👌🏻 To test, give the valve a few sharp taps and see if you get a burst of heat into the cabin. The value is probably sticking. After replacing, my engine warms up quickly and the heat is spot on. Best of luck.
That item you changed I think is a rheostat and controls the fan speed. Not really anything to do with heat just fan speed. I had the same issue with poor heat inside mostly driver side, I removed the heater matrix, not easy and it was half clogged, so new one fixed it.
SMA did a recent video on a repair to deal with a 'blocked heater core' (not for disco mind) that might be worth a watch for future repairs/ideas [reverse flush with some strong cleaner], bit more involved but he seems to have had great sucess with it.
My heat issue is: Driver side has warm heat works normal but passenger side only cold maybe tiniest bit of warmth but the de-mister works well all around
The resistor you changed only regulates the fan speed, the sign that they have failed is when you only have max speed on the fan. If you have no heat coming out it will be a blocked hater matrix. A pig to get too, so try a flush first.
I think all efforts need to be on the engine not getting up to temp before the heater is resolved. I’m sure you said you had tried a drive as well as parked up, it definitely didn’t look like it had temp in any of the video sections. Could it be something like the viscus fan not disengaging? Or maybe the engine IS up to temp but the sensory is under reading and that’s preventing the heating coming on. Can you see engine temps in the Diagnostics. I can’t see how a blocked heater matrix would prevent engine warm up.
It’s the heater matrix. Either flush it out with a hose pipe at the bulkhead hoses or just replace the matrix. Just did mine and it now heats up like it should 100%
LR Time have recently done a video on fixing a Disco 3 heating system might be worth a watch
Fair play for the effort you are putting into this project. It's valuable to those of us who are interested in working on our vehicles, seeing your detailed step-by-step approach.
Wish you are yours a wonderful Christmas and a healthy and prosperous New Year 🙂
My 56 plate sport only got mild heat coming out of drivers side only...I feel blessed....enjoyable content on disco 👊
I had this issue with my D4 and chased a few items to diagnose. I settled on the heater matrix without fully testing - and it was a mistake!
One new matrix fitted (no change), I discovered it to be the diverted/heater control valve mounted behind the webasto unit. £50 Amazon part fitted and it was 👌🏻
To test, give the valve a few sharp taps and see if you get a burst of heat into the cabin. The value is probably sticking.
After replacing, my engine warms up quickly and the heat is spot on.
Best of luck.
I might have to look into that. cheers
That item you changed I think is a rheostat and controls the fan speed. Not really anything to do with heat just fan speed. I had the same issue with poor heat inside mostly driver side, I removed the heater matrix, not easy and it was half clogged, so new one fixed it.
Happy Christmas to you too Fraser.
SMA did a recent video on a repair to deal with a 'blocked heater core' (not for disco mind) that might be worth a watch for future repairs/ideas [reverse flush with some strong cleaner], bit more involved but he seems to have had great sucess with it.
My heat issue is: Driver side has warm heat works normal but passenger side only cold maybe tiniest bit of warmth but the de-mister works well all around
I can’t recall whether you had faults logged re air vent motors. If none logged I would expect it to be the heater matrix. But it’s a pain to swap.
The resistor you changed only regulates the fan speed, the sign that they have failed is when you only have max speed on the fan. If you have no heat coming out it will be a blocked hater matrix. A pig to get too, so try a flush first.
My d2 takes a good 3 miles of driving before it gets to temp and fans starts blowing hot air
I think all efforts need to be on the engine not getting up to temp before the heater is resolved. I’m sure you said you had tried a drive as well as parked up, it definitely didn’t look like it had temp in any of the video sections.
Could it be something like the viscus fan not disengaging? Or maybe the engine IS up to temp but the sensory is under reading and that’s preventing the heating coming on. Can you see engine temps in the Diagnostics. I can’t see how a blocked heater matrix would prevent engine warm up.
We’ll spend some more time on the diagnostic in the new year to see what’s going on. D3s always take an age to heat up especially on idle
Got to be the heater core.
check your heater control valve the blockage could be there
It’s the heater matrix. Either flush it out with a hose pipe at the bulkhead hoses or just replace the matrix.
Just did mine and it now heats up like it should 100%
You have to diagnose the fault first before just part swapping
Judging by the crap that’s in the system you 100% have a partially blocked rad
Rad seems fine but the matrix was completely blocked
@ inner rad I meant 🤦♂️
Take off top pipe and put drain cleaner Costic soda into the rad and flush out, that will sort it