Of course, it is certainly possible that BOTH exhaust gas leakage into the coolant AND a partially blocked radiator are at fault for the multiple symptoms described.  mcneely

---- Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM> wrote:
> Your radiator should still be fine if it's only 5 years old.
>
> when the rad fan is on, plenty of heat-removing air flows through the fins
> on the radiator ..
> should not be an issue there.
>
> if it's the same case, my attention was immediately drawn to the bubbles
> flowing from engine into pressure bottle, if I read that right.
>
> that says exhaust getting into the coolant to me.
> It can be intermittent.
> It's fairly common.
>
> Scott
> ----- Original Message -----
> From: "Travis Newhouse" <travisnewhouse@GMAIL.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Wednesday, September 21, 2011 10:09 AM
> Subject: Re: 85-H20 loss of coolant mystery
>
>
> >> It was fine for a daily drive of 1 mile each way @ 25 mph.
> >> But on the highway @ 55 the cooling system was just too
> >> clogged with rust.
> >
> > That is the opposite of what I'm experiencing, but Loren's suggestion
> > makes sense that high speed air velocity may be enough to keep cool,
> > but the radiator lacks capacity during stop-and-go with only the fan
> > pulling air through the radiator.
> >
> > Loren mentioned that the radiator may not be able to be flow tested.
> > So, how does one diagnose a clogged radiator to decide if it is the
> > problem and should be replaced?
> >
> > The radiator in my 85 Westy was replaced in 2006, and only the blue
> > BMW coolant has been used (50-50 with distilled).  What is the average
> > lifespan before corrosion of the radiator?
> >
> > Thanks,
> > Travis

--
David McNeely