Hot air story

htfx19

Herzel Frenkel
For a long while I was getting hot air blowing into the cabin.
I suspected the regulating valve in the heating unit wasn't shutting off properly (though air wasn't flowing thru) so I installed an inline valve on the hose in the engine compartment leading to the heating unit. NG.
I must add that hot air was coming in only after engine temp reached the 190 deg region.
Then I suspected the channel under body covering the main water tubes along the car. A long time ago I replaced those tubes and doing so I had cut off the channel. So I fabricated a new channel. NG
I then sealed everything along the channel – still NG
Last week my friendly neighbor Nati looked and found out I am missing two small plate, up front under the headlights which leaves an open path for hot air into the front trunk and into the cabin.
End of hot air story, see pics


 
up front under the headlights which leaves an open path for hot air into the front trunk and into the cabin.

I have been battling this too - and best I could work out (by the increase in temperature of my Diet Coke bottles) was that the hot air was coming from the spare wheel area - probably pressurised by the coolant pipe channel. But my attempts to fix it have failed dismally. So I'm obviously wrong.

I have a late model car (and no panels like your photograph). What is this air path you speak of? I would be very happy to fix this one!
 
Path

My car is 1987 which is pretty late model too.
As for path - hot air (from the radiator) builds up pressure in the air dam (that is the volume in the front scoop under the nose. Usually it is directed down and out under the car. These panels are down there in the hi pressure volume and when missing provide a pass-through to the front trunk. I believe there are enough passages from there to the cabin, I haven't traced them.
 
I think they were late model parts

Earlier Xs had indicators mounted to the body



When the indicators were moved to the bumpers a plate was fitted to blank off the original hole. It's the lower "hole" in this next photo



Which the eagle eyed might pick as a car that now resides in Adelaide :grin:

Jim McKenzie has indicators set into these plates, which looks so good and smooth I have acquired all the necessary parts to do the same.

 
I don't get how the absence of those plates would increase flow into the cabin. I put blinkers into them and ditched the bumpers. I always have hot air but my temp control slider doesn't operate full motion so I can't turn the valve off all the way, have to fix that soon. Get's pretty toasty in the cabin sometimes. The space between the bottom of the headlight and the top that plate I filled with a piece of suspended ceiling light lens. I can disable the headlight motors via a switch in the cabin and turn on the headlights they shine those lenses, sorta like little fog lights.
file_zps5dfbbde6.jpg
 
temp control

So you suspect the miss-adjusted temp valve heats up your cabin... but where does the air come from,where would the air that flows through the heating core come from?
I still think it is the plates but haven't checked yet.
 
Kinda Kool, Jeff...

The car is looking awesome as well... clothed in radar resistant flat black and all... HA!
 
Thinking about this today, I'm also struggling to see where hot air in the front compartment can "leak" into the cabin. Effectively there's a double firewall there (with the steering rack in it). The only place I can think is through the wheel wells and down the sills where there are some holes to the cabin (but covered in carpet).

I'm still thinking the coolant pipe channel section is the most likely candidate - especially if the front "plate" is not sealed around the pipes?
 
hot air

check the defroster door at the top of the cowl between the w/w motor and the brake/clutch reservoirs. sometimes it won't close all the way, or the seal is decayed, that is my first thought. if indeed it is coming from the radiator.
get one of those infrared thermometers, drive the car till you really feel the heat.. stop and read all the temps under the trunk and look for the hot spots....
best o luck!!
mikemo
 
I always assumed it was coming in the scuttle vent somehow, it sure feels like it comes through the center console heater duct and picks up heat from the heater core, at least that's my assumption, air is certainly entering mine somewhere.
 
The car is looking awesome as well... clothed in radar resistant flat black and all... HA!

Doesn't look that good anymore. Plasti Dip is wearing thin on the hood, the gloss is showing through, rust holes are rampant again, but it runs good and I'm content :D
 
Hot air

Jvandyke, at least I've found a twin for my problem. You state you have air flowing in (hot or cold)
So now the question is where is it coming from.
 
holes into cabin

My 85 has a large 2.5 inch hole at the front of each side of the cabin. Its in the scuttle under the windscreen for fresh air? Although mine is a UK car this may be different?

I was wondering what these holes are for? Also I only get hot air from the centre vents - is this normal?
 
My 85 has a large 2.5 inch hole at the front of each side of the cabin. Its in the scuttle under the windscreen for fresh air? Although mine is a UK car this may be different?

I was wondering what these holes are for? Also I only get hot air from the centre vents - is this normal?

There should be ducts that connect those to the side vents in the dash. Yes, only the center vents are part of the heater unless you have an air conditioned car. A car with AC has those holes blocked off and hoses running from the side vents to the heater/AC unit.
 
I finally dropped my fuse box for valve access and manually closed the valve, my control cable just won't close it off completely because with manual closure; no heat. I need to re-adjust that cable throw.
 
Soak cable in PB Blaster inside and out... then gently...

exercise it until your full throw is restored. Maybe disconnect the cable to prove its the valve or the cable, or hopefully not both.
 
vent holes

those two round holes are for any water that accumulates in the cowl and drains at the bottom of the car.
mikemo
 
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