That wouldn’t explain why one coolant pipe was cold when I stopped would
it?  The gauge didn’t just instantly change, it was gradual, but fairly
quick.

I think I have a spare thermostat with me, I may install it today. Don’t
have a full set of tools, but I have 10 and 13mm  spanners and I think
that’s all I need.

I neglected to mention this is a syncro, if that matters.

Original oil cooler is still present, no mods there.

Thanks for your assistance Dennis.

-Mark

On Sat, Jan 22, 2022 at 6:34 AM Dennis Haynes <d23haynes57@hotmail.com>
wrote:

> Is it possible that you have a gauge-connection problem? If the engine was
> really going cold it would seem the oil temp would also drop especially if
> still using the original oil to coolant heat exchanger.
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List <vanagon@gerry.vanagon.com> On Behalf Of Mark
> McCulley
> Sent: Friday, January 21, 2022 10:36 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: On road, Having problem, coolant related
>
> I don’t know specifics on the thermostat but it was installed by a shop
> that specializes in Vanagons.  I will ask them when I take it back for
> repair.
>
> We continued to destination, temp gauge was all over the place though
> never too hot. I could not correlate with anything including turning front
> heat on and off. Oil temp stayed steady at around 200F. Ambient air temp
> was 45F not very cold. I will check the bypass valve tomorrow.
>
> Thanks,
> Mark
>
> On Fri, Jan 21, 2022 at 4:42 PM Dennis Haynes <d23haynes57@hotmail.com>
> wrote:
>
> > As the Vanagon has such a massively, oversized cooling system along
> > with an extremely large heater core, getting hit with cold outside
> > air, keeping the engine up to temperature can be a challenge during very
> cold weather.
> > VW became aware of this early on and the fix was the series "F"
> thermostat.
> > This stat features a delayed but fast acting response to temp and the
> > disc that seals the is further gasketed to prevent any bypass while
> > closed. So do you have the correct t-stat? Further, for the correct
> > stat if not of the Vanagon specific design, the lower disc can be too
> > large diameter and cause the stat to wedge and get stuck open. Also,
> > as the bypass will close too early from this excessive cooling will
> > also result from the lack of mixing the hot coolant leaving the engine
> > with the cold coolant coming from the radiator. The thermostat set up
> > is really a mixing valve and part of the goal is for the coolant to
> > always be flowing through the engine keeping the heads and case at the
> same temperature.
> >
> > Next, on top of the thermostat is that small hose and bypass valve.
> > Make sure that valve is closed.
> >
> > Try closing the heater valve to see if that brings the temp up some
> > and next step is block off part of the radiator.
> >
> > Dennis
> >
> >
> > -----Original Message-----
> > From: Vanagon Mailing List <vanagon@gerry.vanagon.com> On Behalf Of
> > Mark McCulley
> > Sent: Friday, January 21, 2022 3:18 PM
> > To: vanagon@GERRY.VANAGON.COM
> > Subject: Re: On road, Having problem, coolant related
> >
> > Thanks Ken. Not optimal, I know but is it safe to continue? Loaded up
> > for
> > 2 days camping with wife and dogs. 75 miles to destination, 40 to get
> home.
> >
> > Sent from my iPhone
> >
> > > On Jan 21, 2022, at 12:11 PM, kenneth wilford <kenwilfy@gmail.com>
> > wrote:
> > >
> > > 
> > > Sounds like thermostat has failed open.
> > >
> > > Ken
> > >
> > >> On Fri, Jan 21, 2022, 3:04 PM Mark McCulley
> > >> <markmcculley@gmail.com>
> > wrote:
> > >> This is a weird one.
> > >>
> > >> Coolant gauge started going LOWER while driving at 65mph for 30 min.
> > Pulled over to check it out, by then gauge was like it was a cold engine.
> > >>
> > >> -GW expansion tank is full.
> > >> -One of the 2 hoses from engine to radiator is cold.
> > >> -Radiator is cold.
> > >> -No coolant leaking.
> > >> -Oil looks good
> > >> -I opened bleed screw on radiator and no air, just coolant.
> > >>
> > >> After stopping 10 minutes I started van and temp came up to normal
> > >> and
> > radiator got hot. Then a get running a few minutes the temp gauge went
> > back down.
> > >>
> > >> I recently had the entire cooling system renewed, new everything.
> > >>
> > >> I have the rear heater core out and both hoses are plugged
> > >>
> > >> Ideas?
> > >>
> > >> -Mark
> > >> 87 Westy
> > >>
> > >>
> > >>
> > >> Sent from my iPhone
> >
>