Having owned my Disco all these years and in the colder seasons had the fuel burner running. But one question I don’t understand is why does it fire up when my Disco is running at normal temp ?
So I came back from a long journey today and the outside temp was at 5 degrees and it fired up so my question is why would it need to fire up when the car is already warm.D3 HSE
3rd Jan 2020 9:20 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10360
To maintain heat.
It’s probably in the lower heat mode
3rd Jan 2020 9:27 pm
Beno2
Member Since: 18 Apr 2009
Location: SE
Posts: 987
I get that from cold but if the vehicle is already up to temperature why would it be necessary?D3 HSE
3rd Jan 2020 9:31 pm
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
I think like all modern diesel engines, they are so efficient if it was not for the webasto they would be running cold, especiallly if running light.
Do not forget even though the temp gauge says it is up to temp it could be lower by quite some margin.
3rd Jan 2020 9:49 pm
Beno2
Member Since: 18 Apr 2009
Location: SE
Posts: 987
So as well as using diesel to run the engine it uses diesel to run the fuel burner? Even when it’s reached temperature .D3 HSE
3rd Jan 2020 11:00 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10360
Yes. This is where emissions rules were 15 years ago.
Imagine what it’s like now
3rd Jan 2020 11:04 pm
Motolab
Member Since: 18 Oct 2019
Location: Sleen
Posts: 1815
Beno2 wrote:
So as well as using diesel to run the engine it uses diesel to run the fuel burner? Even when it’s reached temperature .
So you asked this when lynalldiscovery You all ready gave the answer why...
lynalldiscovery wrote:
Do not forget even though the temp gauge says it is up to temp it could be lower by quite some margin.
What you See on the dail, as „reached“ can be far from reached in reallity....
On the other hand it has probably reached an optimum with help from the FBH, so without the FBH it will cooling to quick and the FBH can not start-stop-start-stop etc. It needs timeBest regards
Harold
Always looking for Pre '55's & Pre war British Motorcycles! knowing or having one for sale? PM please. I visit the UK 6 times a year
Ps. I edit my texts quite often, english is not my native language, so I will edit My “typo’s” etc.
3rd Jan 2020 11:14 pm
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
Beno2 wrote:
So as well as using diesel to run the engine it uses diesel to run the fuel burner? Even when it’s reached temperature .
Yes and yes.
Webasto thermotop 5.2kw will burn approx 0.6 litre per hour at full power, I would guess half that at half power?
In winter your fuel consumption will increse by approx 10 percent.
You can disable the heater by disconnecting the CAN wires, this may save you fuel (depending on what work you do) but the engine will take longer to reach temp (use more fuel) and during light duty work may never reach operating temp (use more fuel), thus making your engine inefficient and dirtier than normal out of the exhaust.
The new euro6 engines have real trouble keeping the exhaust system hot enough to keep the emissions down.
In fact nowadays it is not about the engine at all it is all about the after treatment systems, the engine plays second fiddle.
4th Jan 2020 3:28 am
Motolab
Member Since: 18 Oct 2019
Location: Sleen
Posts: 1815
agree... although The data sheet is a older and less efficient ThemoTopC it gives a good idea..
The ThermoTop V or EVO's in our D3 & 4's are slightly more efficient..
plus de data is based on Full Parkingheater function (from zero to 76 degrees celcius standalone) instead of the auxillarry function, where it works TOGETHER with the engine and only does, lets say 30% of the work on a long drive...Best regards
Harold
Always looking for Pre '55's & Pre war British Motorcycles! knowing or having one for sale? PM please. I visit the UK 6 times a year
Ps. I edit my texts quite often, english is not my native language, so I will edit My “typo’s” etc.
4th Jan 2020 10:23 am
robpenrose
Member Since: 12 Jan 2016
Location: Surrey / SW London
Posts: 2136
My old TD5 defender was terrible for staying at temp.
When I was living in a ski resort, the engine would cool down if not being worked hard with the heater on when it was cold. You could see the engine temp gauge dropping back!
Could have probably done with disconnecting the viscous fan!
Current: D4 HSE
Previous: BMW Z4M Coupe
Previous: Land Rover Defender 90 CSW Td5
Previous: Land Rover Discovery Td5 ES
4th Jan 2020 10:26 am
Beno2
Member Since: 18 Apr 2009
Location: SE
Posts: 987
Thanks for the explanation I understand it better now D3 HSE
4th Jan 2020 2:59 pm
ClassikFan
Member Since: 02 Nov 2016
Location: Surrey
Posts: 1026
robpenrose wrote:
My old TD5 defender was terrible for staying at temp.
When I was living in a ski resort, the engine would cool down if not being worked hard with the heater on when it was cold. You could see the engine temp gauge dropping back!
Could have probably done with disconnecting the viscous fan!
I had the same with my TD5, I was amazed to see the temp gauge going down when sat in a traffic queue in winter time.Just 'cause you got the power... that don't mean you got the right.
8th Jan 2020 2:14 pm
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
robpenrose wrote:
My old TD5 defender was terrible for staying at temp.
When I was living in a ski resort, the engine would cool down if not being worked hard with the heater on when it was cold. You could see the engine temp gauge dropping back!
Could have probably done with disconnecting the viscous fan!
My 200 is the same, has a proper capilliary gauge and takes exactly 5 miles for the stat to fully open, then if you potter through town the temp will drop and the stat shuts, one winter the lowest I saw the engine temp was 75 degc, that made the pants heater even poorer!
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