H4 headlights with buttermilk!?

Benjamin Weste Pearre bwpearre at alumni.princeton.edu
Mon Feb 9 15:28:34 EST 2004

Last April I upgraded to Blau's overwattage Euro headlight kit.  They
worked like a charm, but coming back from skiing on Friday, I noticed
the following:

1) At the gas station, I went to clean the headlight lenses, and found
   that the lights were still on.  Flipping the headlight switch on
   and off again had no effect.  But the lights went out while I was
   washing the lenses.

2) I left home that evening, and noticed that while the left bulb was
   fine, the right bulb was making an odd pattern (ie the filament was
   not in the normal position).  High beams worked about right, but
   it's hard to check exact aim with the H3s going!

3) Turning the lights off and on resulted in the right bulb dying

4) Driving around town I found I couldn't see anything.  The 5w
   parking lights were lit up, but I couldn't detect that the real
   lights were.  But in the Checker parking lot, it seemed that the
   left light was working OK.

5) I replaced the right bulb (damn, it's hard to do that; who the hell
   designed the front of that car???) with a H4 60/55W.  Now it was
   obvious that the left bulb was also dead.  Maybe it had died
   earlier and I just couldn't tell?!

6) Replaced left with another 60/55 (the overwattage ones are hard to
   find, and I believe aren't really important anyway).  They're
   working fine now.

The interesting thing was the post-mortem on the bulbs.  The right one
had cracked (and even left part of itself inside the reflector -- do I
need to go dig that out???).  The left one had also cracked but not to
the point of losing shards.  But both bulbs were coated on the inside
with a white deposit that looked like dried buttermilk or something.
What is this?  Is it normal?  Perhaps enough light would have gotten
through this for me to think that it was working OK in the parking lot
at (4), but I'd be surprised if the buttermilk did not coincide with
the failure.

Skiing was cold, but the bulbs have been happy in colder weather
before.  All seals seemed OK (not that I looked very hard).  I'm
pretty sure I never touched the bulb surfaces, so I can tentatively
rule out hand-oil deposits.

I almost always drive with my lights on, but I've only put about 6k
miles on the car since installing Blau's kit.

Any ideas as to what I should start worrying about?  Do headlights
often turn into cultured dairy products?  Do they die of culture
shock?  Is my alternator sad (it does have 183k miles on it)?  My
battery is a few months old, but the old one lasted 5 years,
indicating that the charging circuit has been somewhat OK fairly
recently...  I don't have an oscilloscope, though...

anyone want to trade for a 1995.5 S6?  ;)


Ben Pearre          1990 200TQA          http://hebb.mit.edu/~ben

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