[Vwdiesel] Vwdiesel Digest, Vol 84, Issue 5

[Dave Cook]

I guess I don't know for sure that it was the cap in all honesty.  I could smell coolant as we drove up the mountain, I was sitting in the passenger seat and had the window down and could detect it.  Since that seemed logical that it was getting exhaust in the coolant and the cap was releasing it, I assumed that was what was going on.  But I guess in reality I was just ASSuming it.  

However, air doesn't need to get in.  Exhaust (presumably from the bubbles in the return to the tank) is getting in and over pressurizing the system, causing the cap to vent the excess pressure, and coolant also escapes when it is being vented as vapor.  This causes the bubbles and eventually the need to add coolant.  We had to add coolant (level dropped enough to set off the beeper) after the 8.5 hour drive to Colorado, and also after driving up the mountain as well as other steep hilly roads.  (So after getting to Colorado, and again after having been there 3 days driving up and down mountains.)

Dave Cook


--- On Mon, 10/4/10, brian gochnauer <brian at gochnauer.net> wrote:
> > I could smell the coolant being
> released from the cap.
> 
> Are you sure it was the ' from the cap' ?? ... while
> driving...
> 
> Like me, my son just when to Colorado Rocky Mtns and sprung
> a leak in the
> EGR coolant lines they are very cheap 'formed' hoses (at
> least on my '04) so
> I replaced with goodyear heater hose; a much heavier duty
> hose.
> For coolant to leave the reservoir; air does need to get
> in; I wouldn't
> assume a cylinder head leak. imho
> 
> BrianG
> Iowa
> 
> Date: Sun, 3 Oct 2010 18:05:38 -0700 (PDT)
> From: Dave Cook <davevw at yahoo.com>
> Subject: [Vwdiesel] '01 Jetta TDI, Head Gasket
> To: Audi-VW-Diesels Group <Audi-VW-Diesels at yahoogroups.com>, 
>   VW Diesel
>        Group <vwdiesel at vwfans.com>
> Message-ID: <940049.17779.qm at web110103.mail.gq1.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
> My friend's TDI Jetta seems to need a head gasket. 
> For some time, it has
> been losing coolant mysteriously.  No leak has ever
> been observed.
>  Recently, I saw bubbles going into the reservoir
> tank.  And on a mountain
> trip, I could smell the coolant being released from the cap
> as the Jetta
> worked to drive up a steep road.
> So I think I will be replacing the head gasket in the car.
> It has 184,000 miles.  We kinda figured that the
> timing belt would be
> replaced, but not the hardware as that was all replaced at
> 130000ish miles.
> So the job can be planned out, what all else would you
> recommend doing at
> that time?  How about the head?  Assuming
> everything looks ok (and checks
> out flat, etc) would you worry about reworking it and
> such?
> Other things to consider?
> Dave Cook
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