What's the purpose of the little "opening" at the bottom of the spare tire well?

[Bmachine]

Rust at the bottom of the spare tire well is a frequent issue. I imagine that cracked or aged trunk seals would be a major cause for water ingress. But I also notice that, after you insert the plastic plug in the center hole under the tie down post, there is a little opening that remains. Clearly, when driving in the rain, that could cause water to get in there. Does anyone know the reason for that opening?



@eriknetherlands , I noticed that you had drawn that extra opening in your repair piece but did not actually cut it. Or maybe you cut it after the pics were taken?

 

[Stevehose]

My guess would be the hole is for draining the spare tire well.

 

[Bmachine]

My guess would be the hole is for draining the spare tire well.

I thought about that too. But that is the purpose of the round plastic plug, isn't it? And if all other things (seals) work correctly, it seems there would be no reason to have a permanently open hole there. Hence the removable plastic one...

 

[lip277]

Looking at the profile of the sheet metal... It may be a by product of the forming (manufacturing) process. I can't recall if my 2002 had a similar feature or...???
I don't think so, but I do not recall directly....

 

[Breiti]

I thought about that too. But that is the purpose of the round plastic plug, isn't it? And if all other things (seals) work correctly, it seems there would be no reason to have a permanently open hole there. Hence the removable plastic one...

When you change the tire in there rain, you put a wert tire in the well and that need a drain.

The round plastic is to cost the big hole that is for production purpose.
When the body comes out of the primer bath, the liquid must drain very fast, otherwise the roof (where the car is hanging on while that process) wil bent due to to much weight.

You got 4 massive cut out in the floor panel also for that purpose.

Breiti

 

[Bmachine]

When you change the tire in there rain, you put a wert tire in the well and that need a drain.

Ah, ok. Wet spare tire. Now that makes sense. Thank you @Breiti

 

[eriknetherlands]

Ah, ok. Wet spare tire. Now that makes sense. Thank you @Breiti

Indeed I did not cut the little extra opening.

Guess I have to avoid getting a wet spare tire then.

 

[Dan Wood]

I am betting it was a poor design based on the assumption that it needed a drain.
I am not aware of any newer cars having drain holes for a spare tire well.

 

[Breiti]

Every car has any kind of drain in the spare well...
Mostly it is constructed in a rubber with a kind of check valve.

Breiti

 

[Fritzie]

Every car has any kind of drain in the spare well...
Mostly it is constructed in a rubber with a kind of check valve.

Breiti

And nowadays those little rubber check valves stuck due to dirt! Resulting in lots of water in the trunk compartiment and damaging a lot of electrical parts. For example the BMW e61 and e90
So the e9 trunk never can be filled with water

 

[jmackro]

I am not aware of any newer cars having drains for a spare tire well.

Many new cars don't have any provision for a spare tire. No spare tire well makes water drainage moot.

 

[Dan Wood]

BMW must have forgot to put the hole in the E24 spare tire well.

 

[Breiti]

Are you sure?
What is that obb the pic?
I don't know the e24.

Maybe anybody smeared it up with putty?

Breiti

 

[Dan Wood]

Are you sure?
What is that obb the pic?
I don't know there e24.

Maybe anybody smeared ir up with putty?

Breiti

I am sure that there isn't a hole like the E9. I will look it over tomorrow and let you know.

 

[Dan Wood]

Are you sure?
What is that obb the pic?
I don't know the e24.

Maybe anybody smeared it up with putty?

Breiti

Breiti
I stand corrected. While there isn't a hole like in the E9, BMW did design 2 small drains where water shouldn't enter while driving and should work to remove water.