Date:         Tue, 23 Jul 96 10:55:09 -0500
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         "W.R. Transue" <trans@castle.net>
Subject:      Re: Bubble in cooling system? '87 Vanagon

-------- REPLY, Original message follows --------

> Date: Tuesday, 23-Jul-96 07:04 AM
> 
> From: Joel Walker              \ Internet:    (jwalker@ua1vm.ua.edu)
> To:   W.R. Transue             \ Internet:    (trans@castle.net)
> 
> Subject: Re: Bubble in cooling system? '87 Vanagon
> 
> On Tue, 23 Jul 1996 00:28:48 -0500 you said:
> >instructions but still no circulation.
> >Did a vapor lock/ bubble get intoduced into the system when the hose
broke
> >and was replaced? I'd run the engine longer to see if it travels, but the
> >temp shots up iin no time. Do I have to drain the whole system? Is it
> >something more serious?
> 
> ?? how do you know there's "no circulation"?? or .. what do YOU mean by
"no
> circulation"?? if you are talking about the big bubble in the top of the
> coolant reservoir (the left tank), it's ok... drive about 10-15 minutes
and it
> should go away. mine does (whenever i've had to replace the coolant temp
> sensor).

OK I guess I need more specificity to detail my problem. After I replaced
that small section of radiator type hose (bridging the engine block w/ a
coolant line), I went to refill the reservoir w/ coolant (I figured  I lost
a significant amount when it sprayed/leaked all over dring the hose burst).
This was further confirmed when I started the engine and the heat light
blinked immediately (I figure for low coolant or for mix which I've been
told the sensor also detects). 

So I fill the empty resrvoir (the main one you fill behind the license plate
) with water to start with (thinking I'll add coolant next batch as the
water circulates). I start the engine, and let it run for a while, thinking
the thermostat will open up the  valeve and coolant will start to flow. But
after a few minutes of running, I see the heat start to creep up slowly, but
steadily towards the top of the indicator, and I shut things down for fear
of a seziure (probably paranoia, but I ain't taking chances!!).

Like any pro mechanic, I THEN break out the shop manual and read about
refilling the coolant (well after the fact!!). It describes the steps of
elevating the front of the vehicle, clamping hoses, opening up bleed nuts
etc. Now I don't have my tools back East yet, so I don't have anything to
elevate the van with (other than the jack), but I do follow the procedures
with the bleed nuts. Coolant starts to run out of the radiator valve bleed
nut (a bit bubbly but seems to subside), but no water which I added to the
reservoir moves at all... and the temp still continues to rise rapidly.

Soooooo..... I figure one of the following has occured:

1) A nasty bubble has gotten into the cooling system and is preventing
coolant from circulating properly (although I had the coolant running out of
the radiator bleed nut which would indicate some circulation is taking place
).

2) A blockage has occured somehow in the cooling system

3) Water pump has failed (but again, there seems to be some flow if its
flowing out of the bleed valve, and also there's no tell tale sounds or
coolant leak to indicate the pump has gone).

4) When the coolant sprayed around its shorted the temp sensor/coolant senor
giving me a false overheat indication (highly unlikely but..)

There's no coolant leak since I replaced the hose.

> 
> if you are talking about the "little hose" that i think you are (the one
that
> goes between the power steering pump belt, into the right side cylinder
head)
> that's an air-bleed hose. notice that it goes up to a "loop" around the
engine
> and that loop is connected to the coolant reservoir.
> 

Hmm. don't know if we're talking about the same hose... The one I replaced
is about 2" long, and probably about 1 1/2" - 2" in diameter (its on the
right hand side of the engine, wedged between the power steering belts and
the alternator belts.. in fact optimally you have to disconnect both belts
to work on this small section of hose). Its not one of those 1/4" diameter
hoses which connects up at the engine compartment bleed valve..

Anyway, I'd sure appreciate any tips about what may be going on (and sorry
for the lengthy description but I thought it might shed some light).

Damn VW sure made filling coolant a bitch.. do you have to go throuigh all
this bleed valve stuff when your topping off coolant on an average day (in
other words when you haven't blown a hose or something)?
 

-------- REPLY, End of original message --------