Heater Intake

[castorcamber]

I have been trying to understand why the heater blows very little warm air. Pipes to and from the matrix get hot so the water system is ok, but still no warm air, in fact there is not a lot of air at all. I have removed the trim in the car to analyse the problem and all the vents look ok and connected. Whilst in the engine bay I noticed that I cant see an inlet for the air. The bonnet has a vent on the rear facing edge (facing the screen)and the underneath of the bonnet had a hole in it that has a rubber sheet glued to it, then i noticed that the front of the bulkhead has the formed ABS plastic cover with an added sheet of ABS pop riveted on it. At this point I realised that there isnt actually anywhere that I can see where the air can get into the heater, Doooh, perhaps that is why there is little air from the heater. But before I start drilling out the pop rivets can someone answer the following.
1. Is the front of the Bulkhead where the heater air intake should be?
2. Is there a vent or tube from the bonnet to this intake? (that is missing on my car)
3. Is there a clever way of getting the air in that I haven't noticed?
Any answers to these questiones would be welcome

[s.hogan3]

on my car it uses the air from the cab and uses this
i found that my water valve was broken in the on poss
i got a new one from vw as the mk1 golf used a simler setup

[leorest]

I've spent ages trying to find where the air gets in. At one point I even suspected it was up in the transmission tunnel somewhere. I've given up now and am resigned to the belief that TVR intended for the top to be down. In all honesty I think that the heater/ventilation was an afterthought. If you get the plastic cover off I'd like to see some pictures of what's behind.

[s.hogan3]

the back of the fan assemble is behind the cover

[Gerry Attrick]

As far as I can establish the heating system (if that's what it's called) merely stirs up the air inside the cabin. The general consensus of opinion is that it's pretty cr4p. I think everyone else just puts another sweater on!

[jchase]

castorcamber,

which heater box do you have? there are about four variants I have seen. I redesigned mine, and it works, demists any weather from cold in 2 minutes and stays demisted. You need to make sure there are no air locks in the matrix, which can be a pain if you have any kind of leak in the coolant system at all. Also, if you have the 2nd type box, made of folded and welded PolyPropylene, you should try sealing all the connections for the air delivery, especially the face vents, and the seal to the demist plenum.

The final, 400se version works the best of the variants I have seen in use, no doubt due to the extra space behind the dash.

I'm probably not going to make another of these, as it took me over a week! If you want one, I'll be happy to make it for you if you pay me a weeks wages!!

-Jim

[badredwedge]

jchase said:

The final, 400se version works the best of the variants I have seen in use, no doubt due to the extra space behind the dash. -Jim

Your right Jim the 400 is as warm as toast even hot enough for wifey and she likes it HOT !!

[blaineuk]

had this problem on the 390, i drilled a couple of big holes in front of the windscreen, so that the air is drawn through the vent in the bonnet that you have got, covred them woth some mesh. made a difference,you could feel the air coming through the vents

[adam quantrill]

On my first 350i it was a mesh at the top of a boxy looking thing in the bulkhead - and the screen wash nozzle poked through the mesh. Haven't looked at the 400SX but will post when I find out, but looking at the pic in your profile I'd suspect it's like the 350i. The 400 is quite toasty but the 350i isn't bad - only struggles if it has been parked somewhere damp all day and then it freezes in the late afternoon.

[brummiewedge]

Yep, my 400 is not bad at all, just the two way fan is not quite enough on low speed and high speed is ballistic and you cant hear yourself think!

[castorcamber]

Thanks for all your help, Yes it is a 350I and on the rear facing edge of the bonnet there is already a mesh covered vent that supposedly is connected to the underside of the bonnet where the 2.5 inch square hole is. It looks like this is supposed to go down through a vent at right angles to point the air flow into the ABS cover under the bonnet on the bulkhead. I will check this this weekend and try to remove the pop riveted cover on the bulk head to see if this can be done. I can see no reason why this should not work. Will let you know. Thanks again for all the help

[badredwedge]

brummiewedge said:

Yep, my 400 is not bad at all, just the two way fan is not quite enough on low speed and high speed is ballistic and you cant hear yourself think!

Yea Brummie but at least if you have the fan on full you cant hear the portable speed limiter screaming down you left ear hole

SLOW DOWN

[andy390]

Hi ,just to let you know, I went down the route of removing the ABS plastic box on the 'bulkhead',just cos i was curious where air was drawn in.
It turns out on a 350 style body (which my 390 is based on) the only air inlet is through an oval opening in the drivers footwell,so, basically ,all you have is an air recycling system, that has no fresh air inlet. No wonder i have seen an amazing variety of TVR/owner modifications when i looked around at the last BBWF! It seems TVR experimented wildly with this area!
There is nothing behind the ABS box apart from a 4 inch hole where the Vauxhall(i think) fan unit draws its air. i have no idea why the shallower part of the box is there...it does nothing.
Not wanting to make any modifications to the external appearance of the bonnet, i cut a neat hole in the top surface of the box,fitted some wire mesh(frying pan splash guard-99p from pound shop!) and used various bits of foam/rubber seals to draw air in from the windscreen area,and even incorporated a metal flap operated by a solid wire choke cable to blank off the fresh air inlet if required.
Hope this is of help
I have photos if you're interested
Andy

[GV]

andy390 said:

Hi ,just to let you know, I went down the route of removing the ABS plastic box on the 'bulkhead',just cos i was curious where air was drawn in. It turns out on a 350 style body (which my 390 is based on) the only air inlet is through an oval opening in the drivers footwell,so, basically ,all you have is an air recycling system, that has no fresh air inlet. No wonder i have seen an amazing variety of TVR/owner modifications when i looked around at the last BBWF! It seems TVR experimented wildly with this area! There is nothing behind the ABS box apart from a 4 inch hole where the Vauxhall(i think) fan unit draws its air. i have no idea why the shallower part of the box is there...it does nothing. Not wanting to make any modifications to the external appearance of the bonnet, i cut a neat hole in the top surface of the box,fitted some wire mesh(frying pan splash guard-99p from pound shop!) and used various bits of foam/rubber seals to draw air in from the windscreen area,and even incorporated a metal flap operated by a solid wire choke cable to blank off the fresh air inlet if required. Hope this is of help I have photos if you're interested Andy