Webasto screeching

Pinkythelabrat

A2OC Donor
I’m back. Sorry I’ve not been around much. I’ve been a dirty flirt and spent the last wee while fixing up a T25 VW camper. It’s for sale now so I can get back to sorting the issues with my car instead of it.

My TDi has the diesel Webasto heater. Recently it has been screaming and screeching whenever it runs. Very Halloween appropriate and turns heads I must say. I turned it off with the ECON button for now.

How easy is it to pull out the Webasto. Anyone done it?

I do have a spare (two actually) and thinknit looks easy enough but I’ve been caught out before.

Any advice?

Alex.


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Doesn't Econ also turn off the A/C compressor on the A2? Not that you'll need it in this weather but I have vague memories of reading that it's always running anyway, and... some... magic happens? to make it only do cold A/C when it needs to? I'm not sure on the ins-and-outs.

Anyway, I mention this as screeching and screaming shouts (heh) motor bearings to me. Do you, or anyone you know, have VCDS as that, amongst other things, will let you briefly fire up the Webasto without the engine running.

Edit. Testing procedure here: https://www.a2oc.net/community/index.php?threads/webasto-remote-heater.25802/#post-203464

Edit 2: There's a fan in the Webasto. Hmm.
 
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It’s the Webasto. The owl runs on for a couple of minutes after the engine stops.

There is indeed an air moving fan in the Webasto which starts before the fuel pump. That would seem the culprit.


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Hi Alex,

It may be the combustion fan screaching, but this is an uncommon issue with the Webasto.
There's not much else that can be causing the noise though, unless the Webasto has a shut-off fault (not going to idle/sleep when reaching a set temperature) and therefore boiling the water in the chamber. This is doubtful, and only really applies if the Webasto is being run in test mode without the engine running.
I would not recommend running the unit in test mode without the engine running as the water in the chamber will boil very quickly if the water pump isn't circulating the coolant.
You could check to make sure the air intake isn't blocked and causing the noise.

Removing the unit isn't an easy task, and is a bit time consuming.
Plainly - it's a faff and awkward, but not overly difficult.
It really needs to come out through the wheel arch, so it's front right wheel off and arch liner out to start with.

If it's not been out before it'll have spring clips holding the hoses in place, so you'll need a decent tool to open them so you can remove the hoses.
You'll loose coolant, so don't forget to have some G13 ready to replace what's lost from the hoses and the the heater itself.

Take care to remove the wiring harnes from the middle of the Webasto carefully, and make sure when re-fitting that they are correctly iinstalled.

One other thing to mention is, make sure the repalcement unit is from an A2.
There are many Thermo Top Z/C-D, but the controller board (electronics) is specific to the A2.
If you have a Webasto from another car it is possible to remove the controller from the A2 item and swap it into the other item.

The combustion air fan can also be swapped, but that will involve splitting the Webasto in half and buying new gaskets.

Last gotcha is to test the replacement unit before fully re-fitting, as many that are sold secondhand don't work at all, and that's very annoying.
I'd fit the hoses and electrial harness and test before re-fitting.

These units can be refurbished and typical parts cost is approx. £200 + VAT.
Typical repair labout charge is £100 +VAT.

Hope this helps
Cheers
Jeff
 
Thanks Jeff,

That’s perfect.

The other units are from A2s and I’ve spun the fan up on one so it’s definitely working - at least the intake fan is.

The owling starts immediately, during the test before fueling so it’s definitely not hot yet.

I’ll take your advice about plugging it in before buttoned no everything up. I’ll maybe have a practice on VCDS as well and see if I can get the test mode to work. I’d rather not be doin* the work at under 7c.

Thanks again.

Alex




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Alex

Freeze spray is perfect to use on the ambient temp sensor that lives just off-centre to the passenger side behind the front grill.

Freeze the sensor for a few seconds and once it detects the chill the Webasto will fire.
Spray the sensor with shorts blasts every now and then to keep the temp low until the Webasto is at full power (about 2 mins normally).

Good luck and let us know how you get on.
Cheers
Jeff
 
No need for freeze spray. Scotland has provided freezing temperatures.

Bonnet off and the owl is definitely in the Webasto. A grinding internal noise and the hooting make me think it’s the fan not turning freely. The air intake is full of grit and is missing an end cap - some dirt has probably been sucked in.

It looks like the Webasto would come out through the bonnet gap if I removed the headlight and the air intake piping. I can see all the fixing bolts I think and it’s not really that big...

Am I being ridiculously optimistic to think so? Has anyone tried this or is the wheel arch the ONLY way?


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Alex,

I've tried twice - a good few years ago now though - and both times ended up removing through the wheel arch.

I too remember thinking it would come out the top, but cannot remember why it wouldn't.
It'll not hurt to try it, and if it won't you know how what to do.
I think it's only 30 mins to remove the wheel and arch-liner, but at this time of year that'll seem like 4hrs.
I might have a go at removing one out of the top this weekend to see what happens, but depends on the time I've got and the weather.

Cheers
Jeff
 
I didn't have time to remove a Webasto today, but looking at the engine mount I don't think there's enough room to angle the unit up and over it, so I still think it's out through the wheel arch.

Cheers
Jeff
 
As a lazy person I’ve tried a soft approach first before stripping the Webasto out.

The end cap for the air intake was missing and the intake area is very very dirty (I found cobwebs!). When putting an ear to the Webasto I can hear grinding from the air fan so I thought maybe just clean it first!

Air intake off and half a can of Wynn’s carb and air intake cleaner later and a new end cap and the air fan seems to be moving without grinding.

I’m a little too cowardly to actually start up the fuelling portion of the Webasto’s function. Since I just filled it full of half a litre of flammable petroleum distillates it felt... unwise.

I’ll try it tomorrow and see whether it worked, didn’t work or whether my car explodes into flame.


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Hi Alex,

That's a much better solution to 4hrs of "fun" taking your car apart

I'll keep my fingers crossed for a result tomorrow.

Cheers
Jeff
 
Thanks Mustang-owner,

That sounds better than ‘lazy’.

first impression is good. Only a very short test driving for 10 minutes. I think I may (possibly) have heard the slightest hint of an owl while sitting with my ear against the side of the car but that was it and certainly not going to be noticeable while driving with the doors closed.

It remains to be seen if this is a lasting solution but fingers crossed.

I also put a new cap on the air intake so hopefully it won’t be made worse. Check your intake baffles people!


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