Hot Air from Fresh Air Vents

fencible39 · Postby **fencible39** » 28 Sep 2012 22:41

I'm trying to understand why I get hot air from my vents when controls are set to vent cold air in through the screen scoop. The door to the hood scoop opens properly, the door to the vents opens correctly, but I can't get cold air, just hot. Somehow it seems that the heater core is adding to the mix. Is there something I'm missing?

Dave Orcutt
1977 FHC Automatic
2007 Hummer H3

Vegas_M · Postby **Vegas_M** » 28 Sep 2012 23:57

Check that the heater shutoff valve is working.
Also, do you have the scoop that fits to the air intake in the engine compartment and prevents engine heat from siphoning in?

Martin

[url="https://docs.google.com/leaf?id=0BxOL0HRH5pDeNWRlOTVhZjgtMWE1Mi00ZWNiLWE3ZGYtOWNiODU1Y2JjOGQ0&hl=en_GB"]My TR7v8 Document Repository[/url]

RJS · Postby **RJS** » 28 Sep 2012 23:57

take a look at this topic:
http://www.forum.triumphtr7.com/topic.asp?TOPIC_ID=17344

Rob

Workshop Help · Postby **Workshop Help** » 29 Sep 2012 01:09

Yes, 'hot' air from the center vents is one of those more or less endearing traits of a TR7. What is happening, provided all else is operating normally, is the very warm, engine heated air is being drawn into the cabin. Even with the scoop tightly sealed against the underside of the hood, the incoming air thru the hood slats, directed into the venting will still be heated. There are those amongst us who also contend the heater core warms the air as well. I don't doubt that. But the main culprit is the engine heat warming the incoming air.

In any event, our cabin temperatures are always about 10 degrees warmer than the outside air. For those souls living in a more temperate climate zone, this is not a bad thing, particularly when the autumnal and winter seasons are present. However, for those who's locale is subject to the soaring temperatures with bonus humidities in the summer, we just plain broil there in the drivers seat and heaven help us if the traffic light stays red too long.

Since most of us do not have air conditioning, one learns to leave the center vents closed, and use the floor vents. The floor vents are fed air thru the fenders and avoid the whole engine heated air issue.

Mildred Hargis

Hasbeen · Postby **Hasbeen** » 29 Sep 2012 03:58

As with our system there is always hot engine cooling water going through the ventilation system, there will always be some heating of the cabin occurring. If the foam on the flap that stops the incoming air going through the heater matrix is degraded, & not working, the heating will be greater.

You can not shut this water flow off, without stopping the flow of hot water from the back of the engine, endangering your cylinder head.

It is a big job to strip the entire dash to recondition the system. This was done to mine, as the airconditioning system was fitted.

However for many years I had made the cabin much more pleasant by bypassing the ventilation system. I simply connected the back of the cylinder head direct to the water pump, rather than through the heater. This is a simple job, requiring a screw driver to work the hose clips, & just a few minutes.

For me, in our climate I have never reconnected it, but in colder climes, it should take less than ten minutes to bypass the thing in mid spring, & reconnect it in mid autumn. Just remove the fresh air plenum, & you'll see the 2 hoses going through the firewall. Change them over, & the jobs done.

Hasbeen

Beans · Postby **Beans** » 29 Sep 2012 07:48

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by fencible39

... Is there something I'm missing? ... <hr height="1" noshade id="quote"></blockquote id="quote">
To answer that it's essential to know what heater you in your car.
The normal one or is the car fitted wit A/C.

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My full Weblog[/url]</center>

DutchTriumph · Postby **DutchTriumph** » 29 Sep 2012 10:02

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Mildred

The floor vents are fed air thru the fenders and avoid the whole engine heated air issue.
<hr height="1" noshade id="quote"></blockquote id="quote">

Are you sure? I thought all the incoming air goes through the scoop.
My FHC has no air vent between the footwell and the fenders.

Cheers,
Peter

1977 TR7 FHC, 1976 Spitfire 1500

Ianftr8 · Postby **Ianftr8** » 29 Sep 2012 11:37

The floor / footwell were a fitment for the California cars ( I think) they do make a big difference as Mildred says. I have them fitted to my car and can thoroughly recommend them.

S&S had at least one pair for sale at the Recent TR Register International meet.

Cheers
Ian

Ian Freeman
1979 TR8 DHC
Triumph Courier
Triumph owner for 31 years

Hasbeen · Postby **Hasbeen** » 29 Sep 2012 11:37

Peter all 7s without airconditioning should have a flap in the outside face of the foot well. These have spring catch. A push opens them, & a pull closes them.

These were not fitted to cars which had airconditioning ex factory.

They do give nice cool air in all but the hottest conditions.

Hasbeen

Beans · Postby **Beans** » 29 Sep 2012 11:57

As far as I know these were not fitted to European cars.
Actually I only know these vents exist, but never seen them in real life.

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My full Weblog[/url]</center>

fencible39 · Postby **fencible39** » 29 Sep 2012 13:05

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Mildred

Since most of us do not have air conditioning, one learns to leave the center vents closed, and use the floor vents. The floor vents are fed air thru the fenders and avoid the whole engine heated air issue.

Mildred Hargis
<hr height="1" noshade id="quote"></blockquote id="quote">

The car has the floor vents but I haven't even tried them yet as I was trying to figure out the hot fresh air vents.

Lots of good suggestions by all received and I have a lot of checking to do now.

It does have A/C but not working as the previous owner removed the a/c fan belt when it got gradually warmer (as the freon waned, as it would with a 35 year old car). I plan to have it recharged next spring with fingers crossed.
Thanks everyone.

Dave Orcutt
1977 FHC Automatic
2007 Hummer H3

DNK · Postby **DNK** » 29 Sep 2012 14:01

Try Ted
http://www.tsimportedautomotive.com/ima ... 5B2%5D.jpg

Don
Stick a Wedge In It
80 TR7 V8 Kick in the pants

fencible39 · Postby **fencible39** » 29 Sep 2012 15:21

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by fencible39

I'm trying to understand why I get hot air from my vents when controls are set to vent cold air in through the screen scoop. The door to the hood scoop opens properly, the door to the vents opens correctly, but I can't get cold air, just hot. Somehow it seems that the heater core is adding to the mix. Is there something I'm missing?

<hr height="1" noshade id="quote"></blockquote id="quote">

Ok, further info:

When the Vent lever (far left)is turned off, and I turn on the fan, air shoots out the driver side vent, far left, and nothing from the middle. When I turn the Vent lever to Max, it shuts off that far left vent and air blows out the center vents. Is something connected wrong or does that sound right?

Dave Orcutt
1977 FHC Automatic
2007 Hummer H3

Spectatohead · Postby **Spectatohead** » 29 Sep 2012 16:22

If the car came from the factory with AC it would not have the floor vents. They can be retro-fitted though. As Don said, you can get them from TS Automotive. Both my TR7 and TR8 came without AC and they have the vents. My heater core is currently bypassed because it leaks. The air coming out of the vents is still warm but maybe not as warm as it was before I bypassed the heater core.

Jim Clark
'80 TR8
'97 Maxima 5spd

fencible39 · Postby **fencible39** » 29 Sep 2012 16:33

[quote]Originally posted by Spectatohead

If the car came from the factory with AC it would not have the floor vents. They can be retro-fitted though. As Don said, you can get them from TS Automotive. Both my TR7 and TR8 came without AC and they have the vents. My heater core is currently bypassed because it leaks. The air coming out of the vents is still warm but maybe not as warm as it was before I bypassed the heater core.

<hr height="1" noshade id="quote"></blockquote id="quote">

Maybe the a/c was dealer added (it's on the original window sticker) but it does have original floor vents with the black plastic turn locks.

Further--I looked at those floor vents yesterday and those are not "turn locks", they're just used to pull open and push closed. I found that once having applied some oil to the area that the springs push them closed quite well.

Dave Orcutt
1977 FHC Automatic
2007 Hummer H3

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