[Vwdiesel] coolant questions
Stephen Kraus
ub3ratl4sf00 at gmail.com
Tue Dec 18 06:32:44 PST 2007
Sorry, I didn't want to sound like a know it all.
I had this problem too about 2 years ago, and decided it would be a good
start to remove the thermostat and check. Sure enough, it was stuck shut and
was causing the engine to boil over.
I actually have a related question.
I have been noticing, though I assume this is only due to the cold weather,
that after my engine heats up to its normal running temp, one I reach
highway speeds, it will cool down all the way to the point below the cold
start temperature. Is that normal for cold weather?
On Dec 18, 2007 9:28 AM, Val Christian <val at mongo.mongobird.com> wrote:
> > Wouldn't that be apparent though? A leaking head gasket would have
> coolant
> > seeping out of it wouldn't it? Not to say that you are wrong, I just
> want to
> > know so I know what I am looking at if this ever happens to me.
>
> No it could be internal, from the cylinder to the coolant.
> I've seen these more often than leaking coolant to the outside.
>
> >
> > It wouldn't hurt to check the thermostat wouldn't it?
>
> I'd agree with that. A passive IR thermometer could be
> your friend.
>
>
> >
> > On Dec 18, 2007 9:22 AM, Val Christian <val at mongo.mongobird.com> wrote:
> >
> > > Your head gasket may be leaking under high pressure, probably with the
> > > engine cold at startup. As the engine heats up, the leaking may
> reduce.
> > > The system stays pressurized at the cap pressure, and may depressurize
> > > as it cools, when the gas is mostly watervapor. When it's exhaust
> > > gases, it doesn't shrink as much when it cools. Also pockets
> > > of gas in the engine will push the coolant out.
> > >
> > > You might do an experimental run with the pressure cap off, and keep
> > > adding fluid (i'd dilute to something like 30/70h2o, to save money)
> > > and see what happens as you idle and lightly run the engine.
> > >
> > > I'm thinking you're right...head gasket. Over the years Ive seen
> dozens
> > > of hg fail on VW, and yours is behaving that way.
> > >
> > > Having said all that, you want to make sure that you don't have air in
> the
> > > system, and that you are not getting hot spots, and that the cooling
> > > system
> > > gets every chance to work properly. Run it unpressurized, and top it
> off,
> > > and then see what happens. Meanwhile, I'd plan the HG replacement.
> > > It's not too bad of a job, but you will probably want to have the head
> > > serviced while it's of. With no complications, and not counting time
> > > going to the machine shop for the head, I figure about 4 to 5 hours
> > > for the job. First time doing it, and I'd budget 15 or 20. Perhaps
> > > others can chime in with their experience.
> > >
> > > Good luck.
> > >
> > > ps: Forget the headgasket in a bottle repairs. Gassers may have a 8:1
> > > vs a 22.5:1 compression ratio.
> > >
> > > pps: Before you pull your head, if you do, please do a compression
> check
> > > on a reasonably warm (100F??) engine. Then you have a baseline.
> > >
> > >
> > >
> > > >
> > > > I had a high temp indication and found the reservoir empty. I filled
> it
> > > and
> > > > still had a high temp indication. When I checked the reservoir it
> was
> > > under
> > > > pressure after sitting all night and blew coolant all over the
> ground
> > > when I
> > > > took off the cap. I siphoned off some coolant to get the level below
> the
> > > > return line from the radiator. It was real cold the next night and
> the
> > > gage
> > > > said it was running hot again. When I checked he coolant, it was
> gone
> > > from
> > > > the reservoir.
> > > >
> > > > I filled it again and started it and there is not immediate
> pressure,
> > > like
> > > > I'd expect from a blown head gasket. It this how a dead thermostat
> > > works?
> > > >
> > > > _______________________________________________
> > > > Vwdiesel mailing list
> > > > Vwdiesel at vwfans.com
> > > > http://www.audifans.com/mailman/listinfo/vwdiesel
> > > >
> > >
> > > _______________________________________________
> > > Vwdiesel mailing list
> > > Vwdiesel at vwfans.com
> > > http://www.audifans.com/mailman/listinfo/vwdiesel
> > >
> >
> >
> >
> > --
> > Stephen T. Kraus Jr.
> > Home: (423)NONE
> > UB3RATL4Sf00 at gmail.com;
> >
> > ------=_Part_13127_26131297.1197987943409
> > Content-Type: text/html; charset=ISO-8859-1
> > Content-Transfer-Encoding: 7bit
> > Content-Disposition: inline
> >
> > Wouldn't that be apparent though? A leaking head gasket would have
> coolant seeping out of it wouldn't it? Not to say that you are wrong, I
> just want to know so I know what I am looking at if this ever happens to me.
> > <br><br>It wouldn't hurt to check the thermostat wouldn't
> it?<br><br><div class="gmail_quote">On Dec 18, 2007 9:22 AM, Val Christian
> <<a href="mailto:val at mongo.mongobird.com">val at mongo.mongobird.com</a>>
> wrote:
> > <br><blockquote class="gmail_quote" style="border-left: 1px solid
> rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Your
> head gasket may be leaking under high pressure, probably with the<br>engine
> cold at startup. As the engine heats up, the leaking may reduce.
> > <br>The system stays pressurized at the cap pressure, and may
> depressurize<br>as it cools, when the gas is mostly watervapor. When
> it's exhaust<br>gases, it doesn't shrink as much when it cools.
> Also pockets<br>
> > of gas in the engine will push the coolant out.<br><br>You might do an
> experimental run with the pressure cap off, and keep<br>adding fluid
> (i'd dilute to something like 30/70h2o, to save money)<br>and see what
> happens as you idle and lightly run the engine.
> > <br><br>I'm thinking you're right...head gasket. Over the
> years Ive seen dozens<br>of hg fail on VW, and yours is behaving that
> way.<br><br>Having said all that, you want to make sure that you don't
> have air in the
> > <br>system, and that you are not getting hot spots, and that the cooling
> system<br>gets every chance to work properly. Run it unpressurized,
> and top it off,<br>and then see what happens. Meanwhile, I'd plan
> the HG replacement.
> > <br>It's not too bad of a job, but you will probably want to have
> the head<br>serviced while it's of. With no complications, and not
> counting time<br>going to the machine shop for the head, I figure about 4 to
> 5 hours
> > <br>for the job. First time doing it, and I'd budget 15 or 20.
> Perhaps<br>others can chime in with their experience.<br><br>Good
> luck.<br><br>ps: Forget the headgasket in a bottle repairs. Gassers
> may have a 8:1<br>
> > vs a 22.5:1 compression ratio.<br><br>pps: Before you pull your head, if
> you do, please do a compression check<br>on a reasonably warm (100F??)
> engine. Then you have a baseline.<br><div><div></div><div
> class="Wj3C7c"><br>
> > <br><br>><br>> I had a high temp indication and found the
> reservoir empty. I filled it and<br>> still had a high temp indication.
> When I checked the reservoir it was under<br>> pressure after sitting all
> night and blew coolant all over the ground when I
> > <br>> took off the cap. I siphoned off some coolant to get the level
> below the<br>> return line from the radiator. It was real cold the next
> night and the gage<br>> said it was running hot again. When I checked he
> coolant, it was gone from
> > <br>> the reservoir.<br>><br>> I filled it again and started it
> and there is not immediate pressure, like<br>> I'd expect from a
> blown head gasket. It this how a dead thermostat works?<br>><br>>
> _______________________________________________
> > <br>> Vwdiesel mailing list<br>> <a href="mailto:
> Vwdiesel at vwfans.com">Vwdiesel at vwfans.com</a><br>> <a href="
> http://www.audifans.com/mailman/listinfo/vwdiesel" target="_blank">
> http://www.audifans.com/mailman/listinfo/vwdiesel
> >
> </a><br>><br><br>_______________________________________________<br>Vwdiesel
> mailing list<br><a href="mailto:Vwdiesel at vwfans.com">Vwdiesel at vwfans.com</a><br><a
> href="http://www.audifans.com/mailman/listinfo/vwdiesel" target="_blank">
> > http://www.audifans.com/mailman/listinfo/vwdiesel</a><br></div></div></blockquote></div><br><br
> clear="all"><br>-- <br>Stephen T. Kraus Jr.<br>Home: (423)NONE<br><a
> href="mailto:UB3RATL4Sf00 at gmail.com">UB3RATL4Sf00 at gmail.com
> > </a>;
> >
> > ------=_Part_13127_26131297.1197987943409--
> >
>
>
--
Stephen T. Kraus Jr.
Home: (423)NONE
UB3RATL4Sf00 at gmail.com;
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