Fuel Burning Heater - What are normal noises?

This is my first winter with a 2006 FL TD4. Am hearing some new noises which I assume are from the Fuel Burning Heater.

After turning off the engine there is a whirring noise which continues for for 30-40 secs then stops. I assume that that is the FBH (seems to come mostly from the metal pipe which emits warm air and which sticks down under the front bumper at the nearside between tow hook & n/s front wheel). And I assume that that run-on is 'normal'.

However, this is what concerns me: consistently when I start up from cold, after about 45 secs with the engine running there is now a quite loud sort-of-medium pitched groaning noise which lasts for about 10 secs. Is that also the FBH? Is it firing up or about to explode? Is a noise like that 'normal'? If not, what does it indicate?

I hadn't realised until now that I had am Oil Fired Boiler under the front of the car - are these things safe? All the manual says is that is cuts in at 5 degrees and is fully automatic.

You've just described the normal operation of one of the most clever inventions ever - the fbh. Without it your engine would take forever to reach normal working temperature.

I've got the optional timer on mine and it's set to run for 30 minutes before I go out to the car in the morning - brilliant.

Engine warmed up and heater / demister has all the windows clear and the interior nice and cosy.

Fantastic thing - no more chance of blowing up than your normal home central heating.

It's a standard Webasto - as fitted to HGVs as a night heater.

Ok thanks Sinvogel. That foghorn noise when it started up scared my wife half to death yesterday - she was walking right in front of it...

Here's a little more info from Harry from another forum.

It's very clear and concise - he's very good is Harry.

Assuming the FBH is working correctly, a temperature switch on the left hand side of the lower grill should (with the engine running) close at below approximately +5C. The FBH will then fire itself up and run, gradually ramping up its output to maximum burn. The FBH will then continue to run until the coolant gets to 74C then drop its output to half power. The process then continues until 77C is achieved and it then shuts down completely. If the outdoor temperature remains below +5C and your coolant temperature falls, the FBH may fire again to bring the coolant back up to temperature. Maximum output is around 5Kw worth of heat transferred into the coolant.

So the basic operation is completely automatic, starting to produce extra heat only when you start to drive the car. An optional extra was a timer, which would run the FBH to warm the car up prior to your starting it, at a set time. Another optional extra was a remote control to trigger it into operation manually from a short distance.

Yes, your wife would have got a surprise - most folks are unprepared and think the car is on fire or such like. Because of the timer I can leave mine running when I'm shopping on cold, icy, or snowy days - I've heard my reg. number being called in Tesco's more than once.

Thanks, great process description. Pity LR didn't put something like that in the manual....