[urq] boiling coolant after shutdown

[Ed Kellock]

Pretty interesting stuff.  Kind of a pain to "install" though.

http://www.evanscooling.com/catalog/C_npg1.htm

On 7/26/05, Justin Riley <jriley at ctiusa.com> wrote:
> How about Evan's Coolant....I have a friend that uses it.  We went to Roebling road in May.  He came in after a run-group, opened the hood, and unscrewed the cap...No pressure...no boilover...
> 
> 
> http://www.lubricationspecialist.com/product_info.php?cPath=9&products_id=124&osCsid=997be34ac028e91d271c0b24e1ae8f19
> 
> No association, just impressed and curious if anyone else has used it.
> 
> -Justin R.
> 
> ________________________________
> 
> From: urq-bounces at audifans.com on behalf of Ed Kellock
> Sent: Tue 7/26/2005 1:19 PM
> To: Urq List
> Subject: Re: [urq] boiling coolant after shutdown
> 
> 
> 
> Well then, you may have told me that I am the culprit, or at least partially so.
> 
> At the outset of this episode, I was leaving the cap loose so as to
> alleviate some leaking when the system pressurized at shutdown.  Since
> then I have left it loose thinking the boiling was happening due to
> another cause.  So this morning, the cap was barely snug, just a
> slight turn after touching the gasket; it was not tightened the way I
> would normally do.  However, even though the cap was only lightly
> snugged, there did not seem to be any pressure escaping before I
> loosened the cap.  The boiling increased when I did and then continued
> after I lightly resnugged the cap to prevent coolant from escaping.
> 
> Maybe I'll steal yet another part from my Cayenne 200 which has been
> "marooned" in the garage for over a year.  ;-)
> 
> Ed
> 
> On 7/26/05, Louis_Alain_Richard at computerhorizons.com
> <Louis_Alain_Richard at computerhorizons.com> wrote:
> >
> > My first culprit would be the reservoir pressure cap (or another small leak
> > permitting a lower system pressure).
> >
> > Following a lister suggestion, I made a low pressure cap (by cutting the
> > spring inside) to give the cooling system a break. Like you, I had many
> > leaks one after the other. My problem with the low-pressure cap was exactly
> > like yours; at shut-off, I was clearly hearing boiling in the head, by
> > burst. I guess the cap must have a good pressure to prevent localized
> > boiling around the exhausts valves. When I put a new cap, and did
> > sufficient cycles to completely bleed the system (which is (notoriously ?)
> > hard to bleed), no more boiling issues.  And no more leaks either...
> >
> > HTH,
> >
> > Louis-Alain
> >
> >
> > urq-bounces at audifans.com wrote on 2005-07-26 12:46:30:
> >
> > > It's very cool here this morning for a change so I decided to drive
> > > the urq to work.  I had the heater valve wide open and the engine
> > > temperature never exceeded normal, the cooling fan did not come on,
> > > even with a minute of idling after reaching work.
> > >
> > > Inside the hose from the neck on the front of the head that goes to
> > > the top of the radiator, the coolant was very obviously boiling.  Is
> > > this even remotely normal?
> > >
> > > History: On June 25th, at 3am, I was on my way to meeting everyone to
> > > go up the road to the Pikes Peak Hillclimb.  I had been driving the
> > > car regularly prior to that and it was running great.  It was cool,
> > > jacket weather still in fact, and I drove very sedately for about 5
> > > miles, stopping off at a 7/11 for some coffee.  When I restarted the
> > > car to leave, the coolant low level warning was on.  A leak had sprung
> > > under the clamp on the lower rad hose at the thermostat housing.  I
> > > refilled and drove a few more miles to the meeting place.  I stopped
> > > and refilled and then drove a short bit more where I finally ditched
> > > the car at the gate of Pikes Peak and rode up with Bruce Bell.  Later
> > > that day, I retrieved the car and drove very carefully and
> > > uneventfully home where a couple days later, I replaced the offending
> > > hose with a spare from Ben Howell (Thanks Ben!) along with a new lower
> > > temp thermostat and a new thermo-time switch at the back of the head.
> > > The next day I drove to work and another leak sprang, in the hose that
> > > goes from the bottom of the coolant recovery tank to the bottom of the
> > > radiator. I replaced that.  The next day the throttle cable came loose
> > > from the pedal in a store parking lot during a hail storm, which being
> > > the third strike in less than a week signalled the beginning of the
> > > cooling off period between the urq and I.  Since then I have only
> > > driven the car home from that store, one quick trip around the
> > > neighborhood a week or so ago and then to work today.
> > >
> > > The boiling in the hose was present back on June 25th, but I figured
> > > it was merely a product of my low/leaking coolant tribulations then.
> > > Now, the system is leak free, with a new thermostat, which obviously
> > > opens earlier and causes the car to run cooler, and the temp on my way
> > > to work this morning was sub-70 and my drive was not spirited, except
> > > for one light blast short-shifting into 2nd, then 3rd, to keep the
> > > boost from falling off.  That wasn't more than a couple hundred yards,
> > > followed by at least a half mile of 4th and 5th at 40 mph or so.
> > >
> > > If you've read this far, thank you, and I appreciate any thoughtful
> > > input you may have.  I'm thinking head gasket, but I tend to be
> > > overreactive and paranoid sometimes, so I'm hoping that's the case
> > > again this time.
> > >
> > > Ed
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