Date: Thu, 14 May 2009 13:14:02 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Thermostat Replacement?
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you hope it's just a thermostat.
that would be very, very nice.
Your semi-'all over the place' symtoms remind me of when exhaust gases get
past the head gaskets and into the coolant .......
which results in odd symptoms - like heaters not
working............'mysterious' getting too hot after 30 or 40 minutes of
running.
Leaks are just leaks -to fix.....external leaks. 'Usually' you start
there - reparing all external coolant leaks.
Theremostats on a 2.1 are pretty easy to get to ( as long as the 4 10mm hex
screws come out ok - I have seen them just spin in the lower t-stat housing
brass threaded inserts .........so be careful there ) ...........
but the t-stat is easy to access, and easy to test.
after external leaks are repaired, and you are sure you have a good t-stat
in there......and it's still acting up.......
determine if it uses coolant in any way.
Generally, if there are no external coolant leaks, and coolant is
dissappearing ......it's going past the joke head gaskets into the
combustion chambers.
If it's doing that - head gasket time.
Some external leaks can be very hard to find. Sometimes coolant may seep
out of somewhere, but get burnt off a warm or hot surface before any drops
hit the ground, making it very hard to spot that leak.
How to know when exhaust is getting into the coolant area of the engine -
The most definitive test is to have the air space above the coolant sniffed
by a smog snifer - there should be almost no HC in the coolant
pressure/expansion bottle. If there is ..........bingo.
Other indications are -
you know it's not the thermostat or water pump because you have checked
those carefully, or replaced them.
You're pretty sure the radiator is able to remove heat under not-extreme
condtions.
You have bled the cooling system to the radiator.
Yet.......it still acts like the main pipes are blocked - the radiator is
stone cold, but the engine if overheating badly ........
and you're sure it's not an externeal leak, or a t-stat, or water pump
failing to circuitlate coolant - then it's most likely this exhaust getting
into the coolant thing.
another indication - you've bled it, you know you have a decent t-stat,
radiator, and w. pump ......and alll is fine and, sometimes intermittantly,
or randomly ........it will just 'not work right' after about 40 minutes of
driving. If you stop and bleed , it's OK again for a while.......
until the next time it 'unbleeds' itself. Head gasket time !
in subaru engines - same thing. In a case or two, they had done everything
in the world to the engine and van regarding the cooling system.
Finally, with nothing else to try, and no real indication that they should
replace the head gaskets, they did anyway, and that fixed it.
and I almost see this 'exhaust' type of head gasket failure more than the
other mopre normal modes of head gasket failure.
And I never saw any engine ever, ever do that ( the exhasut into the coolant
thing ) ..........until the 90's on a turbo diesel vanagon. Since then, I've
seen it on waterboxers, subaru's ..........diesel VW engines in vanagons
........many times. Like 30 cases of this in the last 5 years even.
Scott
www.turbovans.com
----- Original Message -----
From: "Bruce Todd" <beeceetee@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, May 14, 2009 7:55 AM
Subject: Thermostat Replacement?
> My apologies for not paying attention to previous threads on this subject.
> I do archive a number of interesting and helpful emails however I am also
> prone to laziness and after checking my selection of archived material I
> didn't find a conclusion to my question. I know there has been some recent
> discussion and I'm sure overall this has become a tiresome topic for the
> Vanagon Vets.
>
> Here are the symptoms:
>
> Firstly I have 1986 Westy Syncro - 2.1 digifant. The other day I noticed
> a stain / puddle of coolant under the motor area - roughly one foot
> diameter. It seemed the drip was dripping down from the engine carrier
> and
> also trickling down from the oil pressure relief valve. My first thought
> was the water pump finally had packed it in. I checked the coolant fill
> tank but it didn't appear there was much of a loss of coolant - if any.
>
> I jumped in my van and went for a drive as I had a meeting to get to.
> When
> I began my drive the motor was cool but I noticed it heated up very
> quickly
> when driving - much quicker than typical (City driving). No heat from the
> heater - cold cold air from the front heater but regualr heat from the
> rear
> heater. When the temperature guage worked its way fully past the LED -
> the
> low speed fan motor did not operate as it normally would. I was able to
> keep the van from overheating by driving at about 3000 rpm when the guage
> began to climb. Funny enough the front heater would then work
> intermittently - heat and then cold air. When the heat came on it
> appeared
> the temp guage would begin to drop.
>
> Last night I checked the engine compartment and there was no sign of any
> leak - both caps to the expansion and fill resevoir were tight, hoses
> looked
> good and the bottom of the water pump was dry - I don't think any coolant
> is
> coming from the weep hole. I checked the water pump by removing the belt
> and it spun smoothly without significant problem or sound. I ran the
> motor
> and again - no sign of leaking or anything from anywhere.
>
> This morning I awoke to no signs of any leak under my van - everything was
> dry. My first thought is that I need to replace the thermostat - but the
> puddle of coolant under my van yesterday has me wondering...where did it
> come from and why is it not consistently dripping? Is there a link
> somewhere
> between the thermostat and the coolant leak?
>
> So before I purchase the thermostat I thought I'd turn to the group for
> some
> advice.
>
>
> Thanks,
>
>
> Bruce Todd
> 86 Syncro Westy
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