Date: Sun, 24 Mar 2002 14:19:10 EST
Reply-To: VW85Westy@AOL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Peter Krogh <VW85Westy@AOL.COM>
Subject: Re: Coolant Rising Mystery
Content-Type: text/plain; charset="US-ASCII"
In a message dated 3/24/02 1:51:28 PM, mjruskin@shaw.ca writes:
<< Well, simple things first - is it possible your coolant is not concentrated
>enough? If not, it'll boil at low temps. Especially if you have been adding
>pure water to make up for the overflow losses
VW brand coolant at 50/50
>OK, it is concentrated enough, then next idea:
>Are all your bleeder valves tightly closed?: - if not, you'll get air in
>that way - absolutely for sure, and lots of it.
On my '85 the bleeders are 2. The one in the engine compartment, and the
screw on the top of the radiator. I am a little afraid of torquing down the
one on the Radiator for fear of stripping the threads. I am assuming that if
no coolant comes out when it is running at temp and at speed, then no air
will get back in the other way when it is cooling. As to the one in the
engine compartment, it is not the one that bleeds to the outside, but rather
the one that bleeds between the hoses and the crossover coolant pipe. I
assume that this is a closed system and cannot let air in unless defective.
>Less simple: Maybe you're getting some unusual boiling going on - and it's
>pressurizing the coolant and creating steam.
>Which leads me to my next thought - maybe you're getting localized boiling
>in the heads.
>If you go for a drive, stop moving but let it idle for a few seconds - and
>then stop the engine - does it overflow within a minute or two?
>Possible cause: Is the water pump really doing a good job? You seemed to
>have concerns about the water pump. This leads to the next question:
>Is the cooling circulating properly everywhere?
>Other listees can suggest methods for testing these ideas.
Interesting theory. Anybody want to second the plausibility, shoot it down,
or suggest a test.
Thanks,
Peter
----- Original Message -----
From: "Peter Krogh" <VW85Westy@AOL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, March 24, 2002 12:19 PM
Subject: Coolant Rising Mystery
> Okay, folks, I am thoroughly stumped, as well as going broke and sleepless
> over my rising coolant mystery. The short story is that I got a new
engine
> last summer, ran fine for 5000 miles, then coolant starts to creep up.
Have
> heads pulled and evaluated, no problems and re-installed. Problem still
> there. I don't know what the next step is, and I need help. My theories:
>
> 1. there is a hairline crack in one of the heads that only shows up when
the
> head is hot.
>
> 2. There is a leak somewhere in the cooling system where the pressure is
> lowest, say where the returning coolant enters the water pump, and it
sucks
> air in there intermittently. More on that below.
>
> 3. It is leaking in from somewhere in the block
>
> Here's the long story:
> I ordered a new AVP rebuild last spring and had it installed by a mostly
> vanagon shop on Maryland's Eastern Shore, Dick's Autohaus. They did an
okay
> job but were a little sloppy. Eventually, the van was running right, and
I
> put 5000 trouble free miles on it last summer.
>
> At about 5000 miles, I noticed the coolant level rising. This was after
the
> van got hot once (about 2/3 to 3/4 the way up to the red) but did not
> overheat. (Heat tabs on heads intact)
>
> Eventually, I had the heads re-torqued and this seemed to help for a
little
> while. At the end of our long summer sojourn, I noticed that the coolant
> pipes were rusted, as well as the Radiator, and I decided to replace the
> cooling system before pinning the problem on the engine. Replaced
radiator,
> long pipes, most of the molded rubber hoses. Coolant rise still there.
>
> I had the van checked by Wheaton Service Center, by their factory trained
> mechanic, and he could find no hydrocarbons in the coolant, and had no
real
> suggestions beyond radiator cap. He did a pressure test and said that it
> held pressure fine.
>
> Eventually, I took it back to Dick's and had them pull the heads. They
found
> a rolled O ring on one cylinder, but other than that, no sign of leaks or
> overheating. We sent the heads back to AVP and they said they checked out
f
> ine. Dick reinstalled and I drove it home
>
> Coolant level still rises. When I say rises, I mean that it will go from
> normal, to spewing coolant out of the top of the expansion tank. This
> generally takes about 60 to 150 miles. I can let the air out of the
> radiator, bleed the van, and the coolant will return to a normal level.
>
> I have noticed that (in general) in-town driving does not make the level
> rise, only highway driving of more that 15 or 20 miles. My theory is that
> air is getting into the cooling system, but can bleed itself out in town.
> But when the motor is running at extended high RPM's more air gets in than
> can be bled out , and it collects in the radiator, forcing the coolant to
> rise.
>
> Last time I had a big burp in the expansion tank, I took the van by a
local
> shop and tested the air for CO2. The test was negative. Concurrently, I
> found a slight leak in the cooling system in a part I had not replaced,
the
> front heater core valve.
>
> I had a theory that because the heater was high up, it would be an
excellent
> place for air to enter. As the van cooled, perhaps a leak in the front
> heater core would suck air into the cooling system, which would be
> recirculated on the next drive. So I bypassed the front heater and valve
> altogether by attaching the supply and return together above the spare
tire.
> Problem still there.
>
> Could the problem be the water pump? Several years ago, I had the water
pump
> replaced, but the flange was warped. The shop machined it as best they
> could, but it would still leak coolant on the first cold day of the
winter.
>
> When I had the new engine installed, they had some trouble with the water
> pump. Because of the excess milling, they said, when they bolted on the
> water pump, and torqued it down, the bolt punctured the pump. (I think
this
> was the language they used. I am unfamiliar with the geography of a water
> pump and flange) They (I) had to buy another one , and by using shorter
> bolts, were able to make it fit. I see no sign of coolant leaking
anywhere,
> but I wonder about the pump.
>
> The pump is one place that the system could get pressurized. Is it
possible
> that a defective pump could introduce air into the cooling system? Is it
> possible that a less than perfect connection on the low pressure side of
the
> pump could be sucking in air during extended high RPM? This is perhaps
the
> one part of the cooling system that has not been touched since new engine
> installation (I assume that it is left alone during the head R&R)
>
> Here are my questions:
>
> 1. Has anybody ever had air getting into the cooling system that was *not*
a
> cylinder head/gasket leak? Can it come from the block?
>
> 2. What are the next diagnostic steps? I will have the system pressure
> tested, but last time it bore no fruit. I will also have the CO2 checked
> again. Any suggestions on how to test it more thoroughly?
>
> 3. Any suggestions on who could help me with this. I am in the
Washington
> DC area, but would be willing to drive a while to find someone who knows
> vanagons, and could help me.
>
> I've owned this van for 16.5 years, and would hate to have to junk it
after
> spending $6500 in the last year on a new motor. In two weeks, I will be
out
> of the warranty period for the head R&R, and I need to find out if this is
a
> problem with the engine or some other component. We test drove EV
weekenders
> last week, and, although they're nice, they are no Vanagons.
>
> Any suggestions appreciated.
> Peter and Zippy.
