Is the mechanic responsible?

On 2006-03-24, LoupGarou > wrote:

> The mechanic believes it fell out because it was threaded incorrectly.
> I plan on having a second mechanic look at it as well.

A screw that is "threaded incorrectly" is one that has been "cross
threaded". This means the initial thread engagement was not aligned
properly, but engaged enough to start and screw forward at an
incorrect angle and literally forge new threads as it turns. This is
easily detected by revealing two different sets of threads in your oil
pan hole. You should be able to see this. Unless the threads were
completly "stripped" ...the thread peaks literally sheared off from
overtightening (another possibility)... a cross threaded screw is
usually a jammed fit and not likely to come unscrewed. A correctly
screwed thread that was not properly tightened is more likely to come
undone.

If you do detect "crossthreading" or "stripping" of the threads, you
have a much better case in small claims court, as it shows positive
proof of incompetence on the mechanics part. Even if the damage was
done before the last oil change, it was the mechanics responsibility
to make you aware of it. It also shows he was a moron, because it
could have meant a bigger repair job before he ever started the oil
change. So, it's not a likely possibility. If the hole is not cross
threaded, your back to square one and I suspect it is not or the
mechanic that discovered the missing oil plug and replaced it would
have noticed unless they're all idiots in that part of the country and
I doubt they are.... whew!

In the end, I say your best bet is to go to small claims court and
plead your case. The suggestion you may have hit a rock or removed it
again and improperly re-installed it is absurd on the face of it. The
mechanic that replaced your oil was undoubtedly the last to touch it
and having the tow driver's and his mechanic's affidavit is probably
as good as you're going to get. Throw your dice and take your
chances. OTOH, be aware that even if the judge rules in your favor,
that doesn't get you money in your hand. I can't remember all the
small claims court cases I've heard about where the losing defendent
refused to cough up. That's a whole other issue ...and legal problem.
On top of that, all this takes time.

If I were you, I'd bite the bullet, borrow some money from friends,
family, whomever, and get your car fixed now. Learn lifes lessons
and try for satisfaction later.

Good luck
nb

On 2006-03-24, Elle > wrote:

> As for their "brilliant career" choice, most technicians
> I've met are as smart or smarter than doctors or lawyers.

Common knowledge among eng techs for years!

> I write this as a multi-degreed, multi-licensed, extensively
> experienced engineer who still can't perform a clutch job.

Don't beat yourself up over it, Elle.

Naw, just kidding. It's just different skillsets and experience.
Linear-spatial, right brain-left brain, and all that kinda crap.

nb

"notbob" > wrote
> If you do detect "crossthreading" or "stripping" of the
> threads, you
> have a much better case in small claims court, as it shows
> positive
> proof of incompetence on the mechanics part.
snip

> The suggestion you may have hit a rock or removed it
> again and improperly re-installed it is absurd on the face
> of it.

What's absurd about a rock hitting the drain plug and
loosening it or damaging the threads?

This doesn't strike me as impossible.

"notbob" > wrote
> On 2006-03-24, Elle >
> wrote:
>
>> As for their "brilliant career" choice, most technicians
>> I've met are as smart or smarter than doctors or lawyers.
>
> Common knowledge among eng techs for years!
>
>> I write this as a multi-degreed, multi-licensed,
>> extensively
>> experienced engineer who still can't perform a clutch
>> job.
>
> Don't beat yourself up over it, Elle.

Unless you're able to do brain surgery in addition to being
able to change a timing belt, I wouldn't let it go to your
head. :-)

> Naw, just kidding. It's just different skillsets and
> experience.

Yup.

> Linear-spatial, right brain-left brain, and all that kinda
> crap.

Nope. :-)

On 2006-03-24, Elle > wrote:

> What's absurd about a rock hitting the drain plug and
> loosening it or damaging the threads?

Any collision strong enough to rip a drain plug out of its hole, or
even loosen a properly torqued plug, is enough to leave visible
peripheral damage. Too believe a vehicle can drive along and hit a
single "rock" just right, so as to only hit a single apex of a hex
head oil plug, turning it in the "lefty loosey" direction, while
touching no other part of the undercarriage is about as likely as your
mother's left nipple exploding in President Bush's eyeball on the
Fourth of July (this year). Please tell me you don't believe either
one of these possiblities exist.

nb

Elle wrote:
> What's absurd about a rock hitting the drain plug and
> loosening it or damaging the threads?

Firstly, do you know where the drain plug is and which way it faces?

Hey that happened to my Mom...in the future...this coming summer!


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"notbob" > wrote
> On 2006-03-24, Elle >
> wrote:
>
>> What's absurd about a rock hitting the drain plug and
>> loosening it or damaging the threads?
>
> Any collision strong enough to rip a drain plug out of its
> hole, or
> even loosen a properly torqued plug, is enough to leave
> visible
> peripheral damage.

The problem is you're speculating, not asserting provable
facts.

You can't prove that something didn't hit the drain plug and
damage it or cause it to free; or that someone didn't get
under there and free it; or that it's reasonable for a
person to be clueless about the oil pressure warning light.

Any one of those defeats the OP's argument IMO.

"Kaz Kylheku" > wrote
>> What's absurd about a rock hitting the drain plug and
>> loosening it or damaging the threads?
>
> Firstly, do you know where the drain plug is and which way
> it faces?

Yup. Been changing oil in cars for over 20 years.

Do you reject that something could hit the drain plug and
damage it?

I'm not saying it did. I'm arguing it's impossible to prove
that it didn't.

notbob wrote:
> On 2006-03-24, Elle > wrote:
>
> > What's absurd about a rock hitting the drain plug and
> > loosening it or damaging the threads?
>
> Any collision strong enough to rip a drain plug out of its hole, or
> even loosen a properly torqued plug, is enough to leave visible
> peripheral damage.

You know, I would think that even collisions in which the oil pain is
severed and flung 300 yards from the crash site, it will be found with
the drain plug in place.

That is, if it was installed properly: right thread size, with
30-something lb-ft of torque.

> Too believe a vehicle can drive along and hit a
> single "rock" just right, so as to only hit a single apex of a hex
> head oil plug, turning it in the "lefty loosey" direction

Downward inpact on a properly tightened bolt only relieves pressure in
the threads, because they stress acts in the direction which pulls the
bolt into the case. The threads in the case push against the
outward-facing surfaces of the bolt's threads. Moreover, the head of
the bolt is flush with the mounting surface, and so the impact is
transmitted to that surface. There is pressure between the bolt head
and the mounting surface, but in the bolt's shaft there is tension!
I.e. you are not going to strip the threads by hammering straight down
on a a tightened bolt. On the other hand, lateral impact causes shear
which has a tendency to rip the head off. You are right: to loosen the
bolt, a torque impact would be needed, like that of an impact wrench.
Hitting a single rock just right, so that a single torque impact
loosens the bolt, is just about impossible.

And anyway, that's not considering that the bolt is located such that
it does not extend downward beneath the nether profile of the oil pan.
Even if the oil pan bottoms out and scrapes over some pavement or rock,
it's not likely that the bolt will be touched at all. Moreover, because
the bolt is mounted on a rear-oriented surface of the oil pan, it's
shielded from flying objects. You'd have to drive in reverse, at high
speed, on a rocky road, behind some heavy truck that flings rocks into
the air.

But then, I'm not a multi-degreed, certified engineer, so WTF do I
know.