Date: Sun, 13 Jan 2008 01:22:17 -0800
Reply-To: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Subject: Re: Coolant flow/air bleeding
In-Reply-To: <001e01c8559c$ef78f540$0401a8c0@DADSTOSHIBA>
Content-Type: text/plain; charset="us-ascii"
Well, here's my thoughts -
One, it can run with just the pressure bottle and pressure cap working, it
does not 'need' the overflow bottle. Cars never even had overflow tanks
before about the late 60's........there was just an expansion space left at
the top of the radiator below the pressure cap. ( same for pressure bottle
in a vanagon ) so is not going to just 'over heat' just from that hose off,
not from just that alone.
Next, what do you mean by 'overheating.' If it's puking out cooling, and
can't sustain running, yes, that is indeed 'overheating.' If it's just
higher on the temp gauge than you are comfortable with, but other wise
sustains running and doesn't loose coolant or boil over, I call that
'running warm."
Oh, bleeding. ....sure it's gotta be bled. But I have had dozens of engines
out of the van, and never bothered to do 'the final bleed' at the radiator.
Sure, there probably was some air yet at the top of the radiator, and in
summer, for sure, not desirable. My point is that bleeding isn't this hyper
critical you're going to fry your engine if you don't do it really really
good. It SHOULD be done yes, but it's not some hyper critical thing. I've
had all kinds of engine end stuff apart, even whole engines out, and ran
around fine after that without a full bleed at the front job. That's on my
own vans. For someone else out on the road, I'd do the right
thing.........but they can get by super fine without meticulous breathing,
especially at this time of the year. So no need to go too nutty there,
'usually.'
If it can't sustain running and it's full of coolant, checking the
thermostat is usually the first thing you'd do. I don't see them stick shut
very often though, but it's certainly possible.
If you get a case where it just will not sustain running without getting
very hot pretty soon, and you're sure it's full of coolant, and you've
checked the t-stat, and the water pump is turning and the impellers are
good..............and no matter what you do, it's hot engine, cold radiator
- it seems exactly like the main pipes are clogged, ( but they're not
actually ) ........that's what it looks like when you have exhaust gases
getting into the coolant at the head gaskets. The exhaust gases displace
the coolant in the engine quickly, the engine just gets hot right away, like
under 15 minutes, the radiator is stone cold, and you're sure it's not the
thermostat. Just as though the main pipes were clogged. It's not that
uncommon, I hope you don't have this going on.
But that's a very mysterious overheating situation, but happens fairly
easily in waterboxers. In the old days with a head gasket problem usually
the oil got milky. Somehow that almost never happens anymore in engines.
I've see 300 blown head gaskets where the oil never got milky. Then the
next failure mode is coolant goes into the combustion chambers and comes out
the tail pipe. That's an easy one to identify by smell and white clouds
usually. And then there's external coolant leak on waterboxer head gaskets
- that's easy to identify, this fourth failure mode - exhaust getting into
the coolant..........harder to identify. The definitive test is to sniff the
overflow bottle with a smog sniffer, if there's HC in there, that it for
sure.
Scott
www.turbovans.com
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Dennis Haynes
Sent: Saturday, January 12, 2008 8:30 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Coolant flow/air bleeding
One thing to consider is that once you made the decision to drive the van
home after the cooling system failed, you really made the decision to
replace or at least do some repair to the engine. If there was some chance
of escaping damage from the first trauma you chose to continue to damage
things anyway. I have posted many times on the proper way to bled the
cooling system so here it is again.
For starters, after any over heat steam event, the pressure cap and
thermostat should be replaced.
No need to raise the front. In fact that makes it more difficult for the
pump to get the coolant up there.
Since it is winter, consider pre mixing the coolant and water. Just in
case you don't get the vans running long enough to really mix it.
You want to do this with a cold to cool engine.
Fill main pressure bottle, allow time for as much as possible to flow into
the engine. Open the t-stat bypass and both heater valves.
Start the engine and either with a smartly placed screwdriver holding the
throttle or a friend at the gas pedal, get a fast idle, 1,500 2,000 rpm.
Keep the main pressure bottle full. Slowly open radiator bleed. You should
hear some air escaping until coolant flows out. When stream is fairly
steady close bleeder. Top off main or pressure tank and replace pressure
cap. Allow engine to return to normal idle speed. Close bypass, reconnect
hose from cap to overflow. Top off overflow and you are done.
This should be done on 5 minutes or so. Let engine run and feel for
coolant flow to radiator. Idle long enough to test fan operation. If all
is good any small amount of air will work its way out in a few heat-cool
cycles. Check the overflow for a few days as some coolant will get sucked
in. If you see regular bubbling in the overflow tank than failed internal
head gaskets or cracked-loose heads are the likely cause.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
mike stainbrook
Sent: Saturday, January 12, 2008 5:30 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Coolant flow/air bleeding
I have an 85 7 pass,manual trans that has air bubble problem-the line from
fill bottle to resivor worked loose,chopped by fan belt,overheated,I eased
it home,replaced the line,put front end up on ramps,filled resivor and
refill,ran with rpm@2K,heater on,bled from Kennedy valve on radiator,kept
resivor full,got steady flow at first,then as engine heated up,flow
stopped.-still have overheat problem,did get some hot coolant out of bleed
valve.should I assume it's the thermostst sticking? in theory,by closing
resivor and refilling via fill tank,should be able to"recycle" all
coolant.(or,I'm way off base) need input on solution to overheat problem.
Thanks everyone, Mike
mike90260@yahoo.com
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