[Vwdiesel] coolant questions
Val Christian
val at mongo.mongobird.com
Tue Dec 18 06:28:07 PST 2007
> 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;
>
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> 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>;
>
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