Heater fan blowing air OUT of wingtop vent

[Shrubby69]

Hi all,
when my heater fan is running (defender TD5) a LOT of air is being blown out of the wingtop vent.

I presume this can’t be normal? I must be losing a lot of hot air out of the truck, and presumably letting cold air enter the system?

The heater has never been brilliant - thought this might have something to do with it.

Has anyone else had the same thing happen and what would you recommend the fix being - do I simply need to replace all the seals in and around the heater box? And I clearly should done something about it during the summer when it was a bit warmer!

Any thought much appreciated!

 

[mick the builder]

Is your fan going round the wrong way? Has it been messed around with or wiring?

 

[nobber]

Your on/off flap is closed. Does it do it when switched to cold? If not your matrix is blocked.
On the passenger side dash board, remove the vent that blows air around your feet, look through the hole with a torch, you will be able to see the heater vent and you should be able to tell if it is closed or open.

Basically something is blocking the air flow.

 

[Shrubby69]

Is your fan going round the wrong way? Has it been messed around with or wiring?

No - it’s definitely blowing into the cab as well.

 

[Shrubby69]

Your on/off flap is closed. Does it do it when switched to cold? If not your matrix is blocked.
On the passenger side dash board, remove the vent that blows air around your feet, look through the hole with a torch, you will be able to see the heater vent and you should be able to tell if it is closed or open.

Basically something is blocking the air flow.

Hi Nobber.
Pretty sure the flap opens and closes. I get decent air flow into the cab as well - just a lot escaping via the wing vent too. I’ll check again on cold tomorrow and also have a look with a torch.
Need a new seal on the flap maybe?

 

[nobber]

A broken seal wont cause the air flow to come out the wrong way, my guess is the air flow is being restricted. You really need to get in there and have a good look, there could well be crud on the fan itself, if you pull out the plastic chamber leading from the wing to the fan you will be able to look into the fan blades. I think you might have to remove the washer jet reservoir to get it out. Either way it sounds like your heater box needs looking at and its probably best to do it now before it gets really cold and maybe the problem getting any worse.

 

[nobber]

Hi Nobber.
Pretty sure the flap opens and closes. I get decent air flow into the cab as well - just a lot escaping via the wing vent too. I’ll check again on cold tomorrow and also have a look with a torch.
Need a new seal on the flap maybe?

This might be pointing to the fan blades not pushing all the air in the right direction, start by doing what I said above , inspect the fan blades for foreign matter.

 

[Shrubby69]

This might be pointing to the fan blades not pushing all the air in the right direction, start by doing what I said above , inspect the fan blades for foreign matter.

Right - so didn’t have any time today other than I managed to confirm that the same thing happens when hot or cold is selected.

So - job for next weekend is stripping the lot out and having a look.

Thanks for replies - really helpful - will post what I find!

 

[Flossie]

Are you 100% sure it's blowing out the wing top? Mine makes lots of windy type noises but it doesn't actually push air out from there.
If you remove the heater you can still use the truck by linking the two pipes to the matrix with 15mm copper pipe.

 

[Al2O3]

If there's air blowing back out through the wing top how is the air coming in getting past the air that's getting blown out?

 

[Shrubby69]

Are you 100% sure it's blowing out the wing top? Mine makes lots of windy type noises but it doesn't actually push air out from there.
If you remove the heater you can still use the truck by linking the two pipes to the matrix with 15mm copper pipe.

Hi Flossie,
Yeah - you can really feel it if you put your hand over the vent. It’s also definitely leaking round the join between the vent and the heater box (the one with the round foam seal).
Got some copper pipe - going to take it all off at the weekend and strip it down.

 

[nobber]

You wont need to take the whole box out just yet, that tube bit that connects the wing vent to the heater box, remove that and see whats going on with the fan.

 

[Shrubby69]

If there's air blowing back out through the wing top how is the air coming in getting past the air that's getting blown out?

I know - doesn’t make any sense to me either! There must be air getting in somewhere ‘cos it’s getting blown out of BOTH ends of the system!

You wont need to take the whole box out just yet, that tube bit that connects the wing vent to the heater box, remove that and see whats going on with the fan.

Yeah - good call!

 

[FlyingPete]

Defender heaters are notorious for getting blocked up with leaves, dead birds etc and leaking- no wonder people think they're rubbish. I'd go for a thorough approach- take the whole thing apart and investigate. Pull all the assorted crap out, flush the heater matrix with clean water for good measure (you'll be surprised at the colour of what comes out) and put it back together, sealing everything properly. Then see what happens.

 

[Flossie]

Defender heaters are notorious for getting blocked up with leaves, dead birds etc and leaking- no wonder people think they're rubbish. I'd go for a thorough approach- take the whole thing apart and investigate. Pull all the assorted crap out, flush the heater matrix with clean water for good measure (you'll be surprised at the colour of what comes out) and put it back together, sealing everything properly. Then see what happens.

Agreed. The heaters are ok when working properly.
The important things to get right when refurbing is to make sure-
The matrix is good.
The flaps and cables move easily.
ALL air must pass through the matrix and not around it .
ALL air must be shut off by the flaps .
The last two can be achieved by using foam (closed cell camping mats are good) around the matrix and glued to the flaps.
LR did this from new but used a foam that disintergrated over time.
Use new seals for the intake and bulkhead .
Air can also escape from where the matrix pipes poke out, seal them as well.
Keep in mind when fiddling/sealing that you need ALL the intake/fan air to go through the matrix and into the bulkhead with NO losses and you won't go far wrong and know you've got the system running as best as it can.
Set up the cables so you get FULL movement of the flaps and they seal shut nicely inside.
You may find your heater box is rusted out at the bottom which is a pita, source a better one or patch up the old at least ,because your precious air will escape through those holes as well.

 

[Shrubby69]

I’ve had issues with the cables before where the outer wasn’t being clamped properly. Managed to sort that one out thanks to reading about it on the forum!
When I had my rad off during the summer I gave everything a proper flush through with a hosepipe - surprisingly (and disappointingly) it was pretty clean - I was hoping that flushing the matrix would be a quick fix for improving the heater.

After I’d done all that, and was still getting rubbish heating is when I discovered the current issue. I’ll take the wing vent and pipe off at the weekend and have a good look at the fan etc and take it from there.

 

[nobber]

Agreed. The heaters are ok when working properly.
The important things to get right when refurbing is to make sure-
The matrix is good.
The flaps and cables move easily.
ALL air must pass through the matrix and not around it .
ALL air must be shut off by the flaps .
The last two can be achieved by using foam (closed cell camping mats are good) around the matrix and glued to the flaps.
LR did this from new but used a foam that disintergrated over time.
Use new seals for the intake and bulkhead .
Air can also escape from where the matrix pipes poke out, seal them as well.
Keep in mind when fiddling/sealing that you need ALL the intake/fan air to go through the matrix and into the bulkhead with NO losses and you won't go far wrong and know you've got the system running as best as it can.
Set up the cables so you get FULL movement of the flaps and they seal shut nicely inside.
You may find your heater box is rusted out at the bottom which is a pita, source a better one or patch up the old at least ,because your precious air will escape through those holes as well.

I used the liner out of my tool box drawer, not so thick (2mm or so) and quite strong, worked a treat.

 

[zeaphod]

I'd genuinely like to see this "blowing both ways" in action - there's always something new with Tratters! Apart from all the advice above, I'd add check the flexible tubes between the dash vents and dash channel, they easily get kinked/misplaced.

 

[Shrubby69]

I'd genuinely like to see this "blowing both ways" in action - there's always something new with Tratters! Apart from all the advice above, I'd add check the flexible tubes between the dash vents and dash channel, they easily get kinked/misplaced.

Hah - I’ll have a think about how I might be able to video it - think I probably need to find a smoker who’s happy breathing cigarette smoke into my engine bay for a few minutes.

 

[ogb]

Just been through this myself. Details here