Webasto engine coolant pre-heater - horrible noise

[ringo]

Hi,

I was wondering if anyone had any experience of using a engine pre-heater. I have a webasto one that came pre-fitted to my van.

Its great, in that i can set the timer for it to come on an hour before i drive to work, and by the time i leave, the engine is already warm and my wind screen is cleared.

There is one major downside to my unit though - its really loud! Its not just "eberspacher" loud, its completely different and can be heard in the video below:

http://youtu.be/uRPVdBgt3Oo

I suspect the noise is actually coming from the water pump part of it and nothing to do with combustion. However i know nothing of these pre-heaters.

Does anyone have experience of these things? Is this normal?

Pointers and advice much appreciated,

Ringo

[Oldiebut goodie]

I have never touched the water ones but that sounds a bit like there is an air restriction - leaves in the combustion air intake? I wouldn't have expected the pump to be so high pitched.

[lloydy]

I'd agree with that, some boilers sound like that when the air/gas ratio is wrong. Use your hand to partially block the air inlet pipe, see if the noise stops/changes pitch. Check the air inlet pipe for holes, the air and exhaust are meant to be balanced, so if its sucking in air elsewhere air/gas ratio will be wrong

[ringo]

Thanks guys.

You may be onto something.

I took both inlet and exhaust pipes off completely. This made no difference to the high pitched noise at all.

However, when covering the inlet with my thumb, air flow stops and the noise stops.

So does this mean that air is getting into the webasto casing somewhere? I can't see or hear anywhere obvious and there is a lot of suction on the inlet...

Cheers,

Ringo

[lloydy]

i'll say first i know little on diesel heaters, are you completely blocking the inlet, or partially? When this happens on a gas boiler its normally a venturi or heat exchanger starting to block up. So a strip and clean is in order. Basically something has changed the ratio, could be a coked up nozzle, or as you say, sucking in air from somewhere else

[ringo]

Completely blocking it stops the noise.

Looks like i've got a weekend job to do then....

Cheers,

Ringo

[lloydy]

And it still runs with the inlet blocked? or does the noise stop because the fan cuts out? If it carries on running it's getting air from somewhere??
Good luck with cleaning out, take pics, i'm thinking of getting one of these at some stage

[ringo]

I didnt stop it for long enough to stop it as i didnt want to break it. Cool down cycles and all that...

Cheers,

Ringo

[Oldiebut goodie]

I should have a manual for it amongst my collection if you need one and know which model it is.

[ringo]

I should have a manual for it amongst my collection if you need one and know which model it is.

LOL - just found the one you gave me last time i asked

Thanks Goodie...

Ringo