Water Collected in Underbody Panel (Tranny panel)
06-26-2012, 11:44 AM
#1
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My Ride: 2006 BMW 550i "Ben Hogan's 5 Iron"
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2003 Audi A4 3.0 CVT "Part of the Moniker"
Silver/Ebony, Prem, CW, Star 17s
In doing a DIY transmission oil change (an eventful one at that), I noticed a fair amount of water in the large underbody panel after it was removed. Say 12 ounces of water in all. The subject panel covers the tranny oil pan and a number of underbody parts. About 5 days prior, the car was driven 1200 miles across country with the AC on constantly.
Is collecting water here normal and likely due to the long trip with the AC on? Where are there drains or water lines above the tranny? In looking at the transmission itself, there were many white water evaporation marks on the casing that appeared fresh and surely not normal from a design standpoint. I?ve looked at the tranny a few times before and never notice this.
One last strange item to add. The cold air stopped flowing and fan speed dropped significantly (regardless of the high the setting) during the last hour of the nine hour drive. I figured the AC was kaput but it miraculously came back to life during the last 30 minutes of the trip. This was darn odd. The last thing I remembered when the AC returned (after numerous pushing of this and that) was hitting the auto button only. I tend to run the snowflake and auto buttons all the time. Maybe the AC shutdown for its safety, given the system could not cope with 95F temp for 9 nine. Any thoughts?
Is collecting water here normal and likely due to the long trip with the AC on? Where are there drains or water lines above the tranny? In looking at the transmission itself, there were many white water evaporation marks on the casing that appeared fresh and surely not normal from a design standpoint. I?ve looked at the tranny a few times before and never notice this.
One last strange item to add. The cold air stopped flowing and fan speed dropped significantly (regardless of the high the setting) during the last hour of the nine hour drive. I figured the AC was kaput but it miraculously came back to life during the last 30 minutes of the trip. This was darn odd. The last thing I remembered when the AC returned (after numerous pushing of this and that) was hitting the auto button only. I tend to run the snowflake and auto buttons all the time. Maybe the AC shutdown for its safety, given the system could not cope with 95F temp for 9 nine. Any thoughts?
06-27-2012, 12:12 PM
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My Ride: 2006 BMW 550i "Ben Hogan's 5 Iron"
SilverGrey/Black Sport, L7, NAV, CW, AS, Split FR
2003 Audi A4 3.0 CVT "Part of the Moniker"
Silver/Ebony, Prem, CW, Star 17s
06-27-2012, 07:28 PM
#4
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Well, we're not talking about the sump pan are we? Obviously don't drill holes in the cover while bolted to the car.
I am pretty sure that 1/8" holes here and there aren't going to ruin your BMW Efficient aerodynamics!!!!!!!!!
I took my under belly pan off when I changed my tranny fluid a few years ago. I don't have snow so it's not a problem. I get more air cooling to my engine/tranny.
Those are my thoughts. Sorry you feel it's not good advice but its the best advice I can give you sorry. Do what you'd like. your car not mine.
I am pretty sure that 1/8" holes here and there aren't going to ruin your BMW Efficient aerodynamics!!!!!!!!!
I took my under belly pan off when I changed my tranny fluid a few years ago. I don't have snow so it's not a problem. I get more air cooling to my engine/tranny.
Those are my thoughts. Sorry you feel it's not good advice but its the best advice I can give you sorry. Do what you'd like. your car not mine.
06-27-2012, 11:41 PM
#5
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Depends upon where you drive, how you drive and I guess how often you access the bottom of the car for maintenance and how much you hate taking out all of the screws.
I would leave the belly pan on.
Yes, it does have an aerodynamic effect. No, you won't pay for a family trip to Hawaii with the fuel savings but every little bit helps.
Having it in place prevents road dirt and salt (if you are in the Northern states) from coating under body components and accelerating corrosion. It is designed to self drain and small amounts of water will evaporate without affecting anything.
And it provides some protection for components, especially that fairly fragile plastic transmission pan.
Aerodynamically the biggest effect is if you like to occasionally exercise your BMW in a safe manner on a deserted highway at triple digit speeds.
Mind you, I personally would never engage in such an unsafe practice with my 545i.
But if one were to do such a thing they would find that without the belly pan the front end will begin to go light as speed increases. As air builds up under the car because of the missing pan the down force designed into the car's front end is negated. The design of the bottom of a wing is as important as the top of a wing (at high speeds an aerodynamically sound car design is an upside down wing, with down force increasing as speed increases).
While electronically limited to 150mph in the US, the 545i in Germany was claimed to hit nearly 170mph on the Autobahn. At that speed aerodynamics are critical, and BMW is every bit as good as Porsche (I drive both) at designing a car that can cruise all day comfortably at 150mph with no hysterics at the wheel.
But if you start pulling pieces off the car, whether on top or bottom, stability will be adversely affected. Not necessarily noticeable at 60mph but definitely at 80+.
Regarding the protection afforded to components under the car by the belly pan, coincidentally my 545i is presently in the repair shop.
While driving down I-10 west of Phoenix last week the vehicle in front of me ran over a large rubber wheel chock (the type used to prevent semi-tractor trailers from rolling when parked in a dock). After the vehicle in front of me ran over it he spit it out at me. I had vehicles on both sides and couldn't swerve and was forced to run over it.
As I ran over it I heard a loud bang, and immediately the Active Steering warning indicator light illuminated on the dash and iDrive system. The chock struck a lower control-arm on the passenger side and became wedged between the suspension and the road surface. I began to move over to the side and checked my rear view mirror for traffic. Heavy smoke was pouring out from under the car. As I eased off the road onto the shoulder I heard a loud crunch (which was the chock crushing the belly pan as it exited out from under the car at the front passenger door as the drop off in the road level on the shoulder gave it room to escape). I stopped the car and immediately shut off the engine.
I got out to look under the car. I was sure the smoke I had seen was either engine oil or transmission fluid on the exhaust system from loss of a sump pan and expected to see fluid leaking everywhere. But as it turned out the smoke I saw was the burning rubber of the wheel chock as I dragged it along the road. My belly pan was torn up on the passenger side but I wasn't losing any fluids.
I started up and got off at the next exit for a closer look. No fluid loss but after attempting to reset the Active steering the warning light stayed on.
Damage - Tear in front bumper, torn up belly pan, bent hydraulic lines, damaged miscellaneous brackets and damaged steering rack. Steering rack alone is $3K. Total could exceed $6K. If anyone is interested I could post pictures I shot during the insurance adjuster's examination at the dealer. Comprehensive insurance will cover all but deductible, but I am missing my baby.
Without the belly pan in place could the damage have been worse? I believe so. Had the chock taken out both the oil sump and transmission sump at 70mph both the transmission and engine could have been toast in the time it took to pull off the road and turn off the engine. And instead of waiting for repairs I could be shopping for another car after insurance declared it a total loss.
From personal experience I would advise you leave the belly pan on.
I would leave the belly pan on.
Yes, it does have an aerodynamic effect. No, you won't pay for a family trip to Hawaii with the fuel savings but every little bit helps.
Having it in place prevents road dirt and salt (if you are in the Northern states) from coating under body components and accelerating corrosion. It is designed to self drain and small amounts of water will evaporate without affecting anything.
And it provides some protection for components, especially that fairly fragile plastic transmission pan.
Aerodynamically the biggest effect is if you like to occasionally exercise your BMW in a safe manner on a deserted highway at triple digit speeds.
Mind you, I personally would never engage in such an unsafe practice with my 545i.
But if one were to do such a thing they would find that without the belly pan the front end will begin to go light as speed increases. As air builds up under the car because of the missing pan the down force designed into the car's front end is negated. The design of the bottom of a wing is as important as the top of a wing (at high speeds an aerodynamically sound car design is an upside down wing, with down force increasing as speed increases).
While electronically limited to 150mph in the US, the 545i in Germany was claimed to hit nearly 170mph on the Autobahn. At that speed aerodynamics are critical, and BMW is every bit as good as Porsche (I drive both) at designing a car that can cruise all day comfortably at 150mph with no hysterics at the wheel.
But if you start pulling pieces off the car, whether on top or bottom, stability will be adversely affected. Not necessarily noticeable at 60mph but definitely at 80+.
Regarding the protection afforded to components under the car by the belly pan, coincidentally my 545i is presently in the repair shop.
While driving down I-10 west of Phoenix last week the vehicle in front of me ran over a large rubber wheel chock (the type used to prevent semi-tractor trailers from rolling when parked in a dock). After the vehicle in front of me ran over it he spit it out at me. I had vehicles on both sides and couldn't swerve and was forced to run over it.
As I ran over it I heard a loud bang, and immediately the Active Steering warning indicator light illuminated on the dash and iDrive system. The chock struck a lower control-arm on the passenger side and became wedged between the suspension and the road surface. I began to move over to the side and checked my rear view mirror for traffic. Heavy smoke was pouring out from under the car. As I eased off the road onto the shoulder I heard a loud crunch (which was the chock crushing the belly pan as it exited out from under the car at the front passenger door as the drop off in the road level on the shoulder gave it room to escape). I stopped the car and immediately shut off the engine.
I got out to look under the car. I was sure the smoke I had seen was either engine oil or transmission fluid on the exhaust system from loss of a sump pan and expected to see fluid leaking everywhere. But as it turned out the smoke I saw was the burning rubber of the wheel chock as I dragged it along the road. My belly pan was torn up on the passenger side but I wasn't losing any fluids.
I started up and got off at the next exit for a closer look. No fluid loss but after attempting to reset the Active steering the warning light stayed on.
Damage - Tear in front bumper, torn up belly pan, bent hydraulic lines, damaged miscellaneous brackets and damaged steering rack. Steering rack alone is $3K. Total could exceed $6K. If anyone is interested I could post pictures I shot during the insurance adjuster's examination at the dealer. Comprehensive insurance will cover all but deductible, but I am missing my baby.
Without the belly pan in place could the damage have been worse? I believe so. Had the chock taken out both the oil sump and transmission sump at 70mph both the transmission and engine could have been toast in the time it took to pull off the road and turn off the engine. And instead of waiting for repairs I could be shopping for another car after insurance declared it a total loss.
From personal experience I would advise you leave the belly pan on.
06-28-2012, 12:12 AM
#6
Senior Members
I'd have to disagree with your book on aerodynamics. I have it off and although I rarely drive the 5er these days, when i do drive, I cruise about 120-130 and I notice no noticeable difference from when it was on or when i do 50 or 130. It's sitting in my garage.
I'd rather not worry about messing with screws and I'd like to catch leaks when they start rather than later. But most of all I'd like to have my engine and tranny air cooled as well as liquid cooled seeming that the 5 series have had such a wonderful cooling system reputation.
Because my other bimmers undersides are constucted different it's a bit risky to the wheel plastics to not have it on. The E60 doesn't matter.
I'd rather not worry about messing with screws and I'd like to catch leaks when they start rather than later. But most of all I'd like to have my engine and tranny air cooled as well as liquid cooled seeming that the 5 series have had such a wonderful cooling system reputation.
Because my other bimmers undersides are constucted different it's a bit risky to the wheel plastics to not have it on. The E60 doesn't matter.
06-28-2012, 11:00 AM
#7
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My Ride: 2006 BMW 550i "Ben Hogan's 5 Iron"
SilverGrey/Black Sport, L7, NAV, CW, AS, Split FR
2003 Audi A4 3.0 CVT "Part of the Moniker"
Silver/Ebony, Prem, CW, Star 17s
Well, we're not talking about the sump pan are we? Obviously don't drill holes in the cover while bolted to the car.
I am pretty sure that 1/8" holes here and there aren't going to ruin your BMW Efficient aerodynamics!!!!!!!!!
I took my under belly pan off when I changed my tranny fluid a few years ago. I don't have snow so it's not a problem. I get more air cooling to my engine/tranny.
Those are my thoughts. Sorry you feel it's not good advice but its the best advice I can give you sorry. Do what you'd like. your car not mine.
I am pretty sure that 1/8" holes here and there aren't going to ruin your BMW Efficient aerodynamics!!!!!!!!!
I took my under belly pan off when I changed my tranny fluid a few years ago. I don't have snow so it's not a problem. I get more air cooling to my engine/tranny.
Those are my thoughts. Sorry you feel it's not good advice but its the best advice I can give you sorry. Do what you'd like. your car not mine.
06-28-2012, 11:22 AM
#8
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Join Date: Dec 2004
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My Ride: 2006 BMW 550i "Ben Hogan's 5 Iron"
SilverGrey/Black Sport, L7, NAV, CW, AS, Split FR
2003 Audi A4 3.0 CVT "Part of the Moniker"
Silver/Ebony, Prem, CW, Star 17s
Depends upon where you drive, how you drive and I guess how often you access the bottom of the car for maintenance and how much you hate taking out all of the screws.
I would leave the belly pan on.
Yes, it does have an aerodynamic effect. No, you won't pay for a family trip to Hawaii with the fuel savings but every little bit helps.
Having it in place prevents road dirt and salt (if you are in the Northern states) from coating under body components and accelerating corrosion. It is designed to self drain and small amounts of water will evaporate without affecting anything.
And it provides some protection for components, especially that fairly fragile plastic transmission pan.
Aerodynamically the biggest effect is if you like to occasionally exercise your BMW in a safe manner on a deserted highway at triple digit speeds.
Mind you, I personally would never engage in such an unsafe practice with my 545i.
But if one were to do such a thing they would find that without the belly pan the front end will begin to go light as speed increases. As air builds up under the car because of the missing pan the down force designed into the car's front end is negated. The design of the bottom of a wing is as important as the top of a wing (at high speeds an aerodynamically sound car design is an upside down wing, with down force increasing as speed increases).
While electronically limited to 150mph in the US, the 545i in Germany was claimed to hit nearly 170mph on the Autobahn. At that speed aerodynamics are critical, and BMW is every bit as good as Porsche (I drive both) at designing a car that can cruise all day comfortably at 150mph with no hysterics at the wheel.
But if you start pulling pieces off the car, whether on top or bottom, stability will be adversely affected. Not necessarily noticeable at 60mph but definitely at 80+.
Regarding the protection afforded to components under the car by the belly pan, coincidentally my 545i is presently in the repair shop.
While driving down I-10 west of Phoenix last week the vehicle in front of me ran over a large rubber wheel chock (the type used to prevent semi-tractor trailers from rolling when parked in a dock). After the vehicle in front of me ran over it he spit it out at me. I had vehicles on both sides and couldn't swerve and was forced to run over it.
As I ran over it I heard a loud bang, and immediately the Active Steering warning indicator light illuminated on the dash and iDrive system. The chock struck a lower control-arm on the passenger side and became wedged between the suspension and the road surface. I began to move over to the side and checked my rear view mirror for traffic. Heavy smoke was pouring out from under the car. As I eased off the road onto the shoulder I heard a loud crunch (which was the chock crushing the belly pan as it exited out from under the car at the front passenger door as the drop off in the road level on the shoulder gave it room to escape). I stopped the car and immediately shut off the engine.
I got out to look under the car. I was sure the smoke I had seen was either engine oil or transmission fluid on the exhaust system from loss of a sump pan and expected to see fluid leaking everywhere. But as it turned out the smoke I saw was the burning rubber of the wheel chock as I dragged it along the road. My belly pan was torn up on the passenger side but I wasn't losing any fluids.
I started up and got off at the next exit for a closer look. No fluid loss but after attempting to reset the Active steering the warning light stayed on.
Damage - Tear in front bumper, torn up belly pan, bent hydraulic lines, damaged miscellaneous brackets and damaged steering rack. Steering rack alone is $3K. Total could exceed $6K. If anyone is interested I could post pictures I shot during the insurance adjuster's examination at the dealer. Comprehensive insurance will cover all but deductible, but I am missing my baby.
Without the belly pan in place could the damage have been worse? I believe so. Had the chock taken out both the oil sump and transmission sump at 70mph both the transmission and engine could have been toast in the time it took to pull off the road and turn off the engine. And instead of waiting for repairs I could be shopping for another car after insurance declared it a total loss.
From personal experience I would advise you leave the belly pan on.
I would leave the belly pan on.
Yes, it does have an aerodynamic effect. No, you won't pay for a family trip to Hawaii with the fuel savings but every little bit helps.
Having it in place prevents road dirt and salt (if you are in the Northern states) from coating under body components and accelerating corrosion. It is designed to self drain and small amounts of water will evaporate without affecting anything.
And it provides some protection for components, especially that fairly fragile plastic transmission pan.
Aerodynamically the biggest effect is if you like to occasionally exercise your BMW in a safe manner on a deserted highway at triple digit speeds.
Mind you, I personally would never engage in such an unsafe practice with my 545i.
But if one were to do such a thing they would find that without the belly pan the front end will begin to go light as speed increases. As air builds up under the car because of the missing pan the down force designed into the car's front end is negated. The design of the bottom of a wing is as important as the top of a wing (at high speeds an aerodynamically sound car design is an upside down wing, with down force increasing as speed increases).
While electronically limited to 150mph in the US, the 545i in Germany was claimed to hit nearly 170mph on the Autobahn. At that speed aerodynamics are critical, and BMW is every bit as good as Porsche (I drive both) at designing a car that can cruise all day comfortably at 150mph with no hysterics at the wheel.
But if you start pulling pieces off the car, whether on top or bottom, stability will be adversely affected. Not necessarily noticeable at 60mph but definitely at 80+.
Regarding the protection afforded to components under the car by the belly pan, coincidentally my 545i is presently in the repair shop.
While driving down I-10 west of Phoenix last week the vehicle in front of me ran over a large rubber wheel chock (the type used to prevent semi-tractor trailers from rolling when parked in a dock). After the vehicle in front of me ran over it he spit it out at me. I had vehicles on both sides and couldn't swerve and was forced to run over it.
As I ran over it I heard a loud bang, and immediately the Active Steering warning indicator light illuminated on the dash and iDrive system. The chock struck a lower control-arm on the passenger side and became wedged between the suspension and the road surface. I began to move over to the side and checked my rear view mirror for traffic. Heavy smoke was pouring out from under the car. As I eased off the road onto the shoulder I heard a loud crunch (which was the chock crushing the belly pan as it exited out from under the car at the front passenger door as the drop off in the road level on the shoulder gave it room to escape). I stopped the car and immediately shut off the engine.
I got out to look under the car. I was sure the smoke I had seen was either engine oil or transmission fluid on the exhaust system from loss of a sump pan and expected to see fluid leaking everywhere. But as it turned out the smoke I saw was the burning rubber of the wheel chock as I dragged it along the road. My belly pan was torn up on the passenger side but I wasn't losing any fluids.
I started up and got off at the next exit for a closer look. No fluid loss but after attempting to reset the Active steering the warning light stayed on.
Damage - Tear in front bumper, torn up belly pan, bent hydraulic lines, damaged miscellaneous brackets and damaged steering rack. Steering rack alone is $3K. Total could exceed $6K. If anyone is interested I could post pictures I shot during the insurance adjuster's examination at the dealer. Comprehensive insurance will cover all but deductible, but I am missing my baby.
Without the belly pan in place could the damage have been worse? I believe so. Had the chock taken out both the oil sump and transmission sump at 70mph both the transmission and engine could have been toast in the time it took to pull off the road and turn off the engine. And instead of waiting for repairs I could be shopping for another car after insurance declared it a total loss.
From personal experience I would advise you leave the belly pan on.
You like the active steer?
06-28-2012, 11:35 AM
#9
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Senior Members
My wife doesn't drive the car much, but when she does she comments that at slow speeds it feels "twitchy".
Doesn't matter much at highway speeds. I understand the M5 does without it altogether.
What really makes a difference for me is the sport suspension with active roll stabilization, which makes it a real monster in the tight curves while keeping the ride quality soft enough to enjoy highway cruising.
06-28-2012, 12:29 PM
#10
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Senior Members
I'd have to disagree with your book on aerodynamics. I have it off and although I rarely drive the 5er these days, when i do drive, I cruise about 120-130 and I notice no noticeable difference from when it was on or when i do 50 or 130. It's sitting in my garage.
I'd rather not worry about messing with screws and I'd like to catch leaks when they start rather than later. But most of all I'd like to have my engine and tranny air cooled as well as liquid cooled seeming that the 5 series have had such a wonderful cooling system reputation.
Because my other bimmers undersides are constucted different it's a bit risky to the wheel plastics to not have it on. The E60 doesn't matter.
I'd rather not worry about messing with screws and I'd like to catch leaks when they start rather than later. But most of all I'd like to have my engine and tranny air cooled as well as liquid cooled seeming that the 5 series have had such a wonderful cooling system reputation.
Because my other bimmers undersides are constucted different it's a bit risky to the wheel plastics to not have it on. The E60 doesn't matter.
Excerpt from AutoWorld on what BMW thinks:
ERIC MAYNE
Ward's AutoWorld, Sep 1, 2001 12:00 PM
Decades after their European competitors turned aerodynamics upside-down by employing ?belly pans,? Big Three automakers admit they may have underestimated underbodies.
?If you look at their designs, if you look at the actions they have in place underneath the car, the management of airflow, it's obvious that, in the early phases of the program, it was an important design criteria,? says an engineer with one of the U.S. Big Three automakers.
Meanwhile, automakers such as BMW AG were redefining airflow from the ground up. Underbodies have been a priority with the Munich-based automaker since 1980. That's when BMW acquired its first wind tunnel and began development of the 1986 7-Series ? code-named E32.
Today, underbodies rank second ? behind rear ends ? on BMW's aerodynamics checklist, says company spokesman Wieland Bruch. Wheel housings and cooling airflow are third and fourth, respectively.
Such structured protocol helps explain why BMW's X5 sport/utility vehicle boasts a segment-leading drag coefficient of 0.35 ? just 0.03 more blunt than the lower, sleeker Lincoln LS.
And, Mr. Bruch warns, expect an ill wind to blow on BMW's competition this month in Frankfurt. The automaker is unveiling ?a huge step forward? in underbody technology with the debut of its new 7-Series.
?It's an orchestrated/comprehensive approach to optimize underbody airflow, wheel housing resistance, downforce on front and rear,? Mr. Bruch claims, withholding all details except the new 7's 0.29 drag coefficient.
http://waw.wardsauto.com/ar/auto_bottoms/
Article about the Camaro and down force item #5 bellypans
http://media.gm.com/content/media/us..._zl1_aero.html
Article about early aerodynamic research on covering engines to better cool them than leave them exposed.
http://history.nasa.gov/SP-4219/Chapter1.html
At the end of this article engineers talk specifically about how smooth underflow BETTER cools engines.
http://autospeed.com/cms/title_Modif...5/article.html
Even Pat Goss from Autoweek says leave the belly pan in place
http://www.motorweek.org/features/go...e/aerodynamics
If guard duty watching for leaks is that important to you ... I say stay with it.