I suspect that this is going to be one of many Webasto threads over the next couple of months judging by history..
The Webasto has run fine in previous years. I've used the reader on channel 18 aux heating and there are no fault codes. Coolant temperature in the Webasto data reads correct (ie this morning it was cold when I tested it, and gradually increases as the engine warms up correlating within a degree or so of both normal coolant temperature sensor output feeds.) - so it doesn't appear to be the failed Webasto temp sensor issue reading 110 degrees centigrade at startup that others have encountered.
Running the actuator tests I don't see or hear anything with the glow plug run (but I didn't previously either when the pump was working), the fuel supply pump clicks rapidly as normal, and the fan spins up normally.
However, the last few mornings when it has been frosty, simply put the Webasto hasn't run when it would in previous years. The various acceptance criteria I know of for it to work (external temp, coolant temp, alternator voltage, engine running, internal heating system on HI, Econ not activated) were all as I expect them to be.
One thought that comes to mind : a few weeks back I had to fit a replacement diesel heat exchanger on the floor of the car in front of the rear drivers' side wheel. While it was up on the stands, the mechanic noted that what I now know is the fuel pump for the Webasto was hanging loose on its pipes / connection to the loom, so that was cable-tied back into place in the alcove behind the fuel cooler.
Doing a bit of reading about Webasto fuel pumps, I've read something to the effect that their orientation is critically important both for avoiding trapped bubbles, namely that the outlet end (which also has the connection to the loom) needs to be above the inlet end (from the fuel tank). The way that my pump has been secured, the outlet is a good inch lower than the inlet.
see the section marked "pump mounting" on the following page : https://www.letonkinoisvarnish.co.uk/eberspacher_fuel_2.html
from where I have borrowed the following diagram (in case the above page is lost at some point).
Mine is essentially the reverse of the left-hand image, the outlet with loom connector socket is canted around 15 degrees downwards. The pipe to the heater then doubles back on itself towards the centre of the car and then runs to some clips that take the fuel out / return pipes under the car to the engine bay.
Could this be a reason for the Webasto not running - possibly fuel starvation? Is the A2 webasto fuel pump also supposed to be fixed into a specific position?
One further note - I replaced the coolant temp sensor a couple of weeks back and lost the usual amount of coolant. Bled the radiator, but not the Webasto, but then again it wasn't necessary when the thermostat was changed last year so I hoped I'd got away with that. Will go check that now.
I know that running this diesel pump dry can burn it out quickly, so I would rather fix this sooner than later. Any thoughts gratefully appreciated.
The Webasto has run fine in previous years. I've used the reader on channel 18 aux heating and there are no fault codes. Coolant temperature in the Webasto data reads correct (ie this morning it was cold when I tested it, and gradually increases as the engine warms up correlating within a degree or so of both normal coolant temperature sensor output feeds.) - so it doesn't appear to be the failed Webasto temp sensor issue reading 110 degrees centigrade at startup that others have encountered.
Running the actuator tests I don't see or hear anything with the glow plug run (but I didn't previously either when the pump was working), the fuel supply pump clicks rapidly as normal, and the fan spins up normally.
However, the last few mornings when it has been frosty, simply put the Webasto hasn't run when it would in previous years. The various acceptance criteria I know of for it to work (external temp, coolant temp, alternator voltage, engine running, internal heating system on HI, Econ not activated) were all as I expect them to be.
One thought that comes to mind : a few weeks back I had to fit a replacement diesel heat exchanger on the floor of the car in front of the rear drivers' side wheel. While it was up on the stands, the mechanic noted that what I now know is the fuel pump for the Webasto was hanging loose on its pipes / connection to the loom, so that was cable-tied back into place in the alcove behind the fuel cooler.
Doing a bit of reading about Webasto fuel pumps, I've read something to the effect that their orientation is critically important both for avoiding trapped bubbles, namely that the outlet end (which also has the connection to the loom) needs to be above the inlet end (from the fuel tank). The way that my pump has been secured, the outlet is a good inch lower than the inlet.
see the section marked "pump mounting" on the following page : https://www.letonkinoisvarnish.co.uk/eberspacher_fuel_2.html
from where I have borrowed the following diagram (in case the above page is lost at some point).
Mine is essentially the reverse of the left-hand image, the outlet with loom connector socket is canted around 15 degrees downwards. The pipe to the heater then doubles back on itself towards the centre of the car and then runs to some clips that take the fuel out / return pipes under the car to the engine bay.
Could this be a reason for the Webasto not running - possibly fuel starvation? Is the A2 webasto fuel pump also supposed to be fixed into a specific position?
One further note - I replaced the coolant temp sensor a couple of weeks back and lost the usual amount of coolant. Bled the radiator, but not the Webasto, but then again it wasn't necessary when the thermostat was changed last year so I hoped I'd got away with that. Will go check that now.
I know that running this diesel pump dry can burn it out quickly, so I would rather fix this sooner than later. Any thoughts gratefully appreciated.