Member Since: 07 Mar 2009
Location: Clanfield, North of Pompey - UK
Posts: 2819
FBH D3/D4 Differences
I’ve noted some differences between the operation and use of the FBH on my D3 compared to my D4.
I really knew when the FBH in my 2005 D3 HSE was running.
It burnt vigorously, with a good plume of nicely smelling white smoke on a cold morning.
If I started it with the BAS remote starter for 20mins before I needed the car I’d jump in, turn the ignition on, and the temp gauge would jump straight up to normal running temperature, the glowplug light would go straight out, and of course I’d get full heat hot air from the vents.
It was like this with the original FBH and the used one I cleaned out etc to replace the original when it stopped working.
On my 2015 D4 HSE Lux it appears to run a lot ‘weaker’, for want of a better description.
It starts OK with the ignition on a cold morning, or using the Altox controller.
But there is no smoke, a good thing most would think I suppose, but the rate of output from the FBH exhaust is much lower than it was on my D3.
The smell is also acrid, not the lovely comforting smell from my youth of running Paraffin lamps during power cuts.
I’m assuming ‘advances’ have been made and the FBH is running more efficiently, burning a higher percentage of the fuel it’s given, and as such moving less air around to heat things up and dumping less unburned fuel to atmosphere.
If I run the FBH for 30mins using the Altox before using the car the cabin is warm because the blowers are also running, and the windscreen is also defrosted.
But, it’s not fully up to temperature as it was in the D3.
When I turn the ignition on the engine temp gauge stays right at the bottom, jumps up to @1/4 by the end of my road, then takes a mile or so to be fully up to normal temperature.
I’m assuming it’s partly because on the D4 the cabin blowers are also running, moving air around and effectively preventing the coolant getting up to temperature by cooling it via the heater matrix.
But I’d have thought the additional 10mins would have covered that.
Not moaning really, just an observation.
But would like to know if other have seen the same thing in case I need to start thinking about rebuilding my FBH
Nasher.Heaven doesn't want me, and hell is afraid I'll take over.
31st Jan 2020 9:58 am
Bardley
Member Since: 02 May 2018
Location: Hertfordshire
Posts: 473
Some have a valve that diverts the coolant heater/block depending on model. This is likely your experience between cars.2011 MY D4 HSE
Previously 2001 D2 TD5, 1996 D1 300Tdi, 1985 90 2.2 petrol.
Bikes! KTM, BMW, British, Classics and others.
31st Jan 2020 11:03 am
wizbongre
Member Since: 26 Oct 2013
Location: Liverpool
Posts: 697
Exactly the same experience here between D3 HSE and D4 HSE Lux.
I think you’ve already answered half of the query - on the D3 the blowers don’t run, so all heat stays in the coolant; on the D4 the heat will be spent into the cabin via the blower.
I’m also sure (but may be imagining it!) that the D4 has different levels of burn, depending on ambient temp.Cheers,
Gareth
'57 D3 2.7 TDV6 HSE gone and soon to be forgotten!
‘15 D4 3.0 SDV6 HSE Luxury
'64 Audi A6 3.0BiTDi Quattro S-Line Black Edition with lots of toys
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
