Water on trunk liner around tail lights

[tfrain]

I have a recently purchased 1991 BMW 318is.  In really good shape, but I am going over the various and sundry issues.  I had a new muffler put on today, and it is pouring rain outside.  When i returned I opened the trunk to check for leaks and there are some leaks that appear to be situated around the tail lights.  I have read before that the seals around the tail lights can go bad and cause leaks.  I want to attach some pictures to see if it seems this is what is wrong.  It appears the previous owner thought it might be the trunk gasket, because there is some black silicone on the left side where the gasket has a little tear in it. but it doesn't seem to be originating around that area at all.   It hasn't been going on long because there is no rust or rot in the car at all, but I want to address it now.  

Does this seem like the light gaskets?

[DesktopDave]

You're likely right.  The other places that I've found are the upper corners, where the rear sail is tacked on (just inboard of the hinges), and the seal itself.  If the upper part of that seal gets a hole worn into it, water flows into the channel and lets itself into the trunk through several little air perforations on the bottom.

Grab a buddy, a hose, a flashlight and a case of beer.  Put the beer in the trunk, get in the trunk with the beer, have your buddy close the trunk & then hose the car down.  You'll see the leaks more or less...and your buddy will be properly motivated to let you back out...

[tfrain]

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[tfrain]

I can't attach the photos for some reason, but here are some links that will hopefully work.  This is the only place I notice water.  There is a cut near the rear corner of the trunk gasket, directly above the driver side tail lamp that the PO siliconed with black silicon, I guess because they noticed the leak.  This doesn't seem to be the source.  I left it parked outside the muffler shop in the rain, and drove it approx. 3 miles there and 3 miles back in the rain.  Again, there is no rot or rust in either the jack well nor the battery well.  I guess I'll just drop the $50 bucks on new tail light seals first.   Well, I'll probably test as you say first actually.  Yeah, the beer thing is a good idea!!

Anyone know why the tail light seals on 87 to 92 are different and more expensive than the pre 87?  What the heck is the difference.

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[tfrain]

I've tried putting pictures and links on here to no avail.  What am I doing wrong?

[DesktopDave]

Spam filter is naughty to anyone with less than 25 posts.  I approved them, feel free to edit the code for your links.

Later e30's have the larger taillights, different electrical systems and many other detail differences.  Late '87 production date was the cutoff for many of the older e30 design.  Those would have sold as '88 models.  The last major change was the plastic "world" bumpers, integrated fog lights and the sleeker front & rear facia...cutoff was late '88, BMW sold them as '89-on model years.  Convertibles are another entire ball of wax,BTW...

That's a good point you bring up.  Make sure you know the VIN or exact date of production when ordering parts.  The production month/year is on the driver's b-pillar maker's tag.  If you're lucky you can find a build sheet under the rear seat with the exact date of your car's production and originally installed options.  Some dealers will also share that information with you.

[Geoff]

my 91 e30 used to fill up with water in the well for the jack.   I removed both rear light enclosures,  cleaned up the rear panel where the seal goes, clean up the seal,  then reinstalled it with a bead of silicone on the seal.  Its fixed!
                                                                               Geoff

[tfrain]

Dave, you really know your stuff man! How in the world do you know all this stuff?

Geoff, I thought about trying that, but I didn't want to do a bobo job using silicone, but if it worked for you, it could work for me as well.  But I would like to try and avoid spending $50 on some gaskets!

[tfrain]

Also, I'll look under the rear seat for a build sheet.  I'd like to know if my car has LSD or not.

[Geoff]

you jack up the rear of your car, with both wheels in the air & in nuetral,  if you turn 1 wheel by hand, in the direction of forward travel,  if the other wheel turns with the one you are turning, its an lsd.  if it turns in the opposite direction its not.  this tells you what it is, the build sheet tells you what is was when it left the factory:D
                                                              Geoff

[DesktopDave]

Dave, you really know your stuff man! How in the world do you know all this stuff?

LOL, just from making old Kraut iron run 20 years longer than intended...

The best way to test an LSD for function is to test it with the car in gear.  Sometimes the transmission can spin an open diff to make it look like an LSD.  Also, a worn out LSD will look like an open diff regardless.

Some BMW racers test diff function by jacking up one side of the car and using a torque wrench on a lug bolt.  A healthy diff should take about 50-70 ft-lb before it breaks away.  Here's a thread.