Interior heat from engine bay or exhaust
10-20-2017, 09:56 AM
#1
Three Wheelin'
Thread Starter
Interior heat from engine bay or exhaust
MY: 1990; debating whether or not to install dynamat products for reducing interior heat. Not a big issue for me, and would like to hear comments about other experiences.
Not certain if that heat is mostly coming from the engine or from the exhaust?
I have had others cars with real interior heat issues, and this car is not in that category, but if I could make it better, I might be inclined to make some mods.
Floors are in such incredible shape, I am not excited about installing all that sticky stuff.
pros and cons???
Not certain if that heat is mostly coming from the engine or from the exhaust?
I have had others cars with real interior heat issues, and this car is not in that category, but if I could make it better, I might be inclined to make some mods.
Floors are in such incredible shape, I am not excited about installing all that sticky stuff.
pros and cons???
10-20-2017, 10:07 AM
#2
Nordschleife Master
Are the cats in good working order? Any reason to think that the sensors might be malfunctioning and causing the engine to run with ignition retarded? Any overheating issues with the engine itself?
10-20-2017, 10:08 AM
#3
Administrator - "Tyson"
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Something is wrong, time to investigate.
If everything is in place & working as intended (exhaust heat shields, torque tube insulation under shifter, HVAC vacuum pods all functioning etc...) these cars are not known for having interior heat issues.
My 87 has "phantom" warmth issues due to all my vacuum diaphragms behind the dash leaking. I'm going to tackle that this winter.
If everything is in place & working as intended (exhaust heat shields, torque tube insulation under shifter, HVAC vacuum pods all functioning etc...) these cars are not known for having interior heat issues.
My 87 has "phantom" warmth issues due to all my vacuum diaphragms behind the dash leaking. I'm going to tackle that this winter.
10-20-2017, 10:27 AM
#6
Administrator - "Tyson"
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Again, a stuck or slow moving flap due to leaking vacuum actuator will allow a very unnoticeable source of heat to migrate into the cabin.
That's my 87, you swear the cabin is just slowly getting warmer, you cannot feel any moving air, the source is impossible to locate and really only happens when moving with outside air forcing it's way through the system.
27 year old rubber diaphragms, if they've never been replaced the chances of them being 100% are very slim. Even a slight leak.... like one of mine which would only hold 5" (should be 15) can cause such issues.
That's my 87, you swear the cabin is just slowly getting warmer, you cannot feel any moving air, the source is impossible to locate and really only happens when moving with outside air forcing it's way through the system.
27 year old rubber diaphragms, if they've never been replaced the chances of them being 100% are very slim. Even a slight leak.... like one of mine which would only hold 5" (should be 15) can cause such issues.
10-20-2017, 10:40 AM
#7
Nordschleife Master
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10-20-2017, 10:51 AM
#9
Drifting
Base on recommendation from Hans, I used RAAMAT and Ensolite when I had my interior out. It made a huge difference on reducing road noise and cabin heat. I double downed on the torque tube hump.
http://www.raamaudio.com/
If you do decide to apply this stuff, I highly recommend a roll of the shiny peel and stick furnace tape to seal all the joints. The black sticky stuff get everywhere if you are careful. Clean ups easily with goo gone.
https://rennlist.com/forums/attachme...ivers-side.jpg
http://www.raamaudio.com/
If you do decide to apply this stuff, I highly recommend a roll of the shiny peel and stick furnace tape to seal all the joints. The black sticky stuff get everywhere if you are careful. Clean ups easily with goo gone.
https://rennlist.com/forums/attachme...ivers-side.jpg
10-20-2017, 11:27 AM
#11
Administrator - "Tyson"
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10-20-2017, 11:57 AM
#12
Three Wheelin'
Thread Starter
hacker, how can I make anything better, with critiques!! all very welcome!
I overlooked the belly pans, and can see how those would reduce temperatures.
still wondering about installing insulation, and most timid about putting down
sticky stuff over my nice beautiful floor (that is never seen by anyone..lol)
I overlooked the belly pans, and can see how those would reduce temperatures.
still wondering about installing insulation, and most timid about putting down
sticky stuff over my nice beautiful floor (that is never seen by anyone..lol)
10-20-2017, 12:40 PM
#14
Chronic Tool Dropper
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Road test... Drive with the windows down and see if that causes more heat around the console area. The torque tube insulation is a formed foam block that's held up in the tunnel by the torque tube. With either engine or transmission mount sag, the foam drops down some and you lose the seal against the tunnel. Heat from under the car, particularly from the exhaust at the cats, is drawn into the car. Opening the windows or the sunroof creates a lower pressure in the cabin that causes more hot air to be drawn in around the shifter area in the console.
Until a few years ago we lived in the Los Angeles area, where there are only a few weeks of the year when AC isn't used. My half-high transmission mounts allowed a little hot air intrusion, but with windows up and AC running it was not really noticeable. Moving to central Oregon brings on a lot more days when driving with windows down is possible. Hot air coming through the console area moved closer to the front of my project list. Fortuitously, I noticed a couple drops of oil on the floor a couple springs ago after winter hibernation. Good reason to go in for OPG and motor mounts a year ago before hibernation, and a follow-up with new transmission mounts when even the taller Volvo motor mounts alone weren't sufficient to restore the seal. New transmission mounts finished the job, allowing me to drive with windows down and no hot console area.
The motor mount diagnosis is pretty simple. The mounts sit between a couple safety hooks that normally sit all but touching each other. With the belly pan off, you can reach up and feel the space between the hooks. If you can slide a pinky finger between the hooks, the mounts are sagging. Folks often use visual cues like the height of the bottom of the oil sump vs the height of the crossmember. In my S4, new factory mounts cause the top of the intake manifold to line up about half an inch above the crossbrace, using a steel scale on the manifold. The Volvo mounts add to that some since they are taller.
At the transmission, the mounts normally have a cavity under the top bolt that you can easily stck a finger into. When the mounts collapse, that cavity shrinks or disappears. Telltale visuals include a little over an inch of clearance between the rear crossmember and the bottom of the differential housing with good mounts, using a small scale against the rear face of the crossmember. The differential housing is sloped there and there are undoubtedly some slight variations in where the gearbox sits, so this is hardly precise. A better measure might be on the front face of the crossmember to a relatively flat section of the housing, but by the time you get the car up to take that measurement you can just as easily reach up and feel for the clearance in the mount itself. You -may- be able to see the left-side mount looking through from the left wheel well area past the front of the battery box. Still easier to just reach up and do the digital (with a digit...) measuring and know for sure. Folks with fully collapsed transmission mounts report that the differential housing is all but or maybe even touching the crossmember.
Over the years and maybe decades, folks have kludged some sagging mounts by putting urethane spacers between the crossmember and the oil sump in front, and between the rear crossmember and the transmission housing in the rear. These are definitely not long-term options, but might help you identify torque tube foam leaks as your heat source.
All that said, I'd still put insulation in place on the firewall and tunnel areas after the leaks are solved. The Rammat and Dynamat-stype products help dampen low frequencies passing through the floor, and offer a little thermal benefit on the way. There are thermal-only insulating/radiant barrier materials that don't need to be glued down. Replacing the tired foam under carpets and mats helps a lot too. That stuff fails with age and heat exposure to the point it starts to crumble and collapse. Even some creative work with common carpet padding will help in most cases.
Until a few years ago we lived in the Los Angeles area, where there are only a few weeks of the year when AC isn't used. My half-high transmission mounts allowed a little hot air intrusion, but with windows up and AC running it was not really noticeable. Moving to central Oregon brings on a lot more days when driving with windows down is possible. Hot air coming through the console area moved closer to the front of my project list. Fortuitously, I noticed a couple drops of oil on the floor a couple springs ago after winter hibernation. Good reason to go in for OPG and motor mounts a year ago before hibernation, and a follow-up with new transmission mounts when even the taller Volvo motor mounts alone weren't sufficient to restore the seal. New transmission mounts finished the job, allowing me to drive with windows down and no hot console area.
The motor mount diagnosis is pretty simple. The mounts sit between a couple safety hooks that normally sit all but touching each other. With the belly pan off, you can reach up and feel the space between the hooks. If you can slide a pinky finger between the hooks, the mounts are sagging. Folks often use visual cues like the height of the bottom of the oil sump vs the height of the crossmember. In my S4, new factory mounts cause the top of the intake manifold to line up about half an inch above the crossbrace, using a steel scale on the manifold. The Volvo mounts add to that some since they are taller.
At the transmission, the mounts normally have a cavity under the top bolt that you can easily stck a finger into. When the mounts collapse, that cavity shrinks or disappears. Telltale visuals include a little over an inch of clearance between the rear crossmember and the bottom of the differential housing with good mounts, using a small scale against the rear face of the crossmember. The differential housing is sloped there and there are undoubtedly some slight variations in where the gearbox sits, so this is hardly precise. A better measure might be on the front face of the crossmember to a relatively flat section of the housing, but by the time you get the car up to take that measurement you can just as easily reach up and feel for the clearance in the mount itself. You -may- be able to see the left-side mount looking through from the left wheel well area past the front of the battery box. Still easier to just reach up and do the digital (with a digit...) measuring and know for sure. Folks with fully collapsed transmission mounts report that the differential housing is all but or maybe even touching the crossmember.
Over the years and maybe decades, folks have kludged some sagging mounts by putting urethane spacers between the crossmember and the oil sump in front, and between the rear crossmember and the transmission housing in the rear. These are definitely not long-term options, but might help you identify torque tube foam leaks as your heat source.
All that said, I'd still put insulation in place on the firewall and tunnel areas after the leaks are solved. The Rammat and Dynamat-stype products help dampen low frequencies passing through the floor, and offer a little thermal benefit on the way. There are thermal-only insulating/radiant barrier materials that don't need to be glued down. Replacing the tired foam under carpets and mats helps a lot too. That stuff fails with age and heat exposure to the point it starts to crumble and collapse. Even some creative work with common carpet padding will help in most cases.
10-20-2017, 01:52 PM
#15
Three Wheelin'
Thread Starter
all great ideas!
will check out the mounts
I can tell you. with windows down, and only at a full stop, I can feel warm air coming from OUTSIDE the car, from the middle section
thinking about those belly pans, but brakes and fuel lines and intake refresh seem to be ahead of them. priorities......
the good news, is that this issue is so minor and really not a bother.
will check out the mounts
I can tell you. with windows down, and only at a full stop, I can feel warm air coming from OUTSIDE the car, from the middle section
thinking about those belly pans, but brakes and fuel lines and intake refresh seem to be ahead of them. priorities......
the good news, is that this issue is so minor and really not a bother.
