I have been having an issue with hot air coming in from somewhere under the dash. The problem arose when I changed from my d16 to a b16. The engine runs at the proper temp. (about half way on the gauge)

I made sure the temp on the heater is set too cool, and the vent is not set to floor and recirculates inside air. I also made sure that the motors and cables for the settings all work the way they are supposed to. I also tried switching the fresh air vent both ways.

So after that seemed to be a dead end i tried to check where the air was coming from specificly. It was not coming from the floor vents but behind them somewhere. So I checked all the gromets and various hole plugs on the firewall and they all seem to be there.

Now I'm stumped. Does anyone have any ideas?

 

turn the heater off

jk... is it just warm by your feet or is there actual hot air BLOWING from somewhere?

 

Im pretty sure itn not just radiating its actually blowing but it seems to be associated with the car moving. Like its found an opening in the firewall to come through when car is moving and air is being forced through. Only problem is I've looked all over and no such opening.

 

I just thought of another possible explanation. Anyone think it is possible that the door speakers are moving the hot air radiating off the firewall? They are MB Quart QSD 216s they get fairly loud so i would imagine they move a substantial amount of air. If this is the case does anyone have an idea of how to reduce the amount of heat that is passed into the passenger compartment through the firewall??

 

man Im having a very similiar problem. and it sucks cause I dont have a/c and its 103 degrees outside here in savannah. I have no idea what is causing it, but when I change the air to inside flow, it seems to stop it almost completely so Im just doing that for now.

 

Yeah, when it is set to outside air the car pulls air into the system kind of like ram air the movement of the car forces it in. My problem is changing to inside air doesnt help. Ive checked to make sure the button actually works, and it does switch between in and out. Its almost like thiers a hole in the firewall that i cant find or the heat is really intense and radiating through the firewall. Im trying to think of a way to better insulate the firewall itself. Any ideas?

 

that sucks especially now in the summer. but I really dont know what it is, or what to do.

 

i got the same problem with my cars. Im guessing it has nothing to do with speakers cuz i dnt have speakers on my rex, only on my hatchy, n its the same shiite on both... What i find out to lower the am0unt of hot air, is swiching to the window defogger... Stil having it off u dig?

 

See but the air isnt coming out of the floor vent, I cant figure out where it is coming from. I'm starting to think it is just the heat from the firewall I'm feeling. But i know what you mean.
Have you tried switching from outside air to inside air? (you know the two little buttons on the top right of the climate control panel) That keeps air from outside from being forced in.

 

i knw its n0t c0ming from the vent, but idk why, it makes a difference... Lol its s0me weird ****, but i guess its only hapening to us... Jaja n ive tryed the air thing with no luck... Go0d thing dat only happens to me on long trips n n0w i got the odyssey with a/c, so inker jr is co0l on the back... Lol

 

This is some of the funniest stuff I have read in a LONG time.

Its just the air circulating while you are driving!!!!!!!! And the firewall is radiating heat. Close your windows while driving and your current will go away.

Its that simple.

 

I dont understand why its funny? I mentioned before that i suspect the heat from the firewall. I cant close the windows while driving because its in the high 90s here and I have no air. Hence the reason i would like to try and better insulate the firewall. This is my DD so I spend a lot of time in it.

 

Check the rubber boot that seals the shifter to the body. My buddy had a 240sx that he converted to manual and didnt have said piece, blew hot air right at your feet. Also smelled like a truck, but thats par for 240s

 

Thanks Ill check that out. Does anyone have any experience with how the steering coulmn is sealed where it goes throught the firewall? Is there anytype of rubber seal maybe?

 

If you have the car pulling air from outside... thats just the air from the bay because thats where its pulled from...

 

I mentioned in my first post that the vent is set to recirculate inside air. I thought that was the prob at first too though. Its either air leaking in through the firewall or its just heat radiating off the firewall. And I checked just to be sure that the problem is the same with the windows up or down (someone earlier said that was the reason). Begining to think its a lost cause. Maybe ill get some of the dynamat heatshield stuff and try insulating the firewall with that. Anyone have any experience with this?

 

you know that little thing that moves in your engine bay when you turn your climate control to hot or cold? try messing with that, just unhook and try in different positions and see what happens. worth a shot.

 

did u ever figure it out because it pretty annoying. never did it before intill i swaped it

 

i've had this same issue. the hot air also seems to come from the tranny "hump". i'm sure it's just heat build-up that's finding it's way in, but it's no fun. and i can't roll my windows up either. it's too hot with them up.

 

A very common issue with the 4th gen. Radiant heat FTL

 

if the heat is coming from the shifter/exhaust tunnel, you might be able to rig up a heat sheild for the exhaust/cat.
and make sure the rubber boot that seals up the hole for the shifter is in place.

 

Sorry every one but I've been away for awhile. (I just took the Rex to N. Carolina and back with no probs ). Well the problem seems to be better. I found that there is another hole next to the one where the main harness enters the engine bay (sorry i dont know what its for prob A/C or something i dont have. ) well it had been over looked, probably when the engine bay was repainted. I plugged it up and it helped with the hot air being forced toward your feet. There is still quite a bit of hot air down there though. I talked to one guy that said the Dynamat hood liner is excelent for insulating the cabin from the firewall and other hot spots (under the shifter).



I think its like $50 for a 32x54 inch piece. Its not real thin though its about 3/4 inch thick. He said the dynamat extreme also works though not as well, however it is very thin like 1/16 of an inch. BTW he restore classics and builds kit cars for a living and this is what he uses himself (the hoodliner). IMO he seems reliable.

 

@ graftuner
Yeah mine wasn't an issue until after the swap either. My thoughts are the B16 or other B series engines produce a lot more radiant heat, but i've said it before and I will say it again "I am no expert".

 

yep, im still having this problem too, and it sucks cause it makes the 100 degress turn to 110 degrees. but just turning it to inside flow air seems to help a lot. make sure that that **** is working on your car. cant think of anything else besides buying that stuff that guy told you to get, or just wait untill winter, and you wont have to use your heater

 

If you remove the insulation from the firewall on the inside and the engine bay you will definitely experience a rise in radiant heat.

I just choose to live with it.