[Vwdiesel] Water pump not pumping

[lbaird119 at aol.com]

  Ok, you've checked if the impeller is loose on the shaft and it's not.  So, it has to pump so long as it's a real impeller.  Someone on the list once had an impeller that was a square with bent over corners, that had rusted off...  Not much of an impeller to start with.
  Next is if you have an air bubble.  Easy to do if you don't fill it "correctly."  Pull the top radiator hose off from the radiator.  Fill the engine and radiator, through the top hose, going into the engine.  Once coolant starts to run out (bend the hose up to fill) then quickly connect the hose then finish filling through the reservoir.  Start the car and warm it up.  First watch the coolant return flow, into the top of the reservoir.  You should have a solid, steady stream, at fast idle, once a few bubbles clear out.  If that's good, then put on the cap and finish warming up the engine.
  Once the thermostat opens, you can shut it down, wait a few minutes and top off.  Once again check your return stream.  A slight blurp of air now and again isn't perfect bur not unusual.  Constant air is a problem.  A leaking head gasket will put out a pretty steady stream of bubbles.  A blown one generally blows coolant out of the reservoir, IF it'll run at all.
  Be sure to turn the heater to hot at first (to chase out any air) then to cold while you warm it up (it'll warm up faster).  After topping off, check that all is working.   If you suspect a blown head gasket, try the heater as you drive.  If it loses heat then stop and loosen the cap slightly.  If you get excessive pressure, (but didn't have bubbles) then you likely have a bad cap.  With the cap slightly loosened, see if heater function and more or less, normality returns.
     Loren



-----Original Message-----
From: Erik Lane <eriklane at gmail.com>
To: vwdiesel <vwdiesel at vwfans.com>
Sent: Sat, Feb 15, 2014 11:16 am
Subject: [Vwdiesel] Water pump not pumping


Hello all,
I'm looking for some ideas. I've run out, at least for the moment. This is
n a 1981 Jetta with a 1.6NA diesel. No modifications to the system - I
ust replace parts when they wear out with the stock replacements.
Driving home from work one day, that also happened to be about the coldest
ay around here, I had no heat and the temperature gauge was getting
ncomfortably high as I was getting close to home. I was worried that I had
ost all my coolant or something, but I was close enough to home and it was
ising slowly enough that I was able to make it without getting anything
nto danger zones. (Plus it was cold and snowing with no good spot to leave
t.) Though I live near Portland, OR, so our cold is not like most of you.
t was probably mid 20s.
I got home and checked it, and it was full of coolant. After puzzling over
t and letting it cool I took everything apart, thinking that maybe the
mpeller had come off the shaft. That wasn't the case, and even using those
ubber band strap wrenches to get a really good grip, I couldn't budge it.
 tried tapping with a punch and hammer to see if the impeller would move
t all on the shaft in or out, and it wouldn't.
I replaced the thermostat, cause I had one on the shelf, and it seemed like
 long shot, but I was running out of ideas. I drove it around a bit after
utting it back together, and it acted up again. I looked at it, and the
oolant bottle was completely full, but it still hadn't even sucked down
ny coolant into the radiator. In the past I've always been able to fill
hese cars by only putting coolant in the fill bottle and running the
ngine a bit to pump it around the system.
I've got it apart again, and I've put the exhaust from a shop vac up to the
ole in the block to see if there were any restrictions, and coolant came
hooting out of every hose that I had open. When I go to drain the system,
 open all three hoses down at the water pump, and water comes out of them
ust fine. I also have an inline tee in the hose to the heater core that a
revious owner installed - it's one of those that comes with a radiator
lush kit and has a screw on cap to be able to purge the system. So using
hat I know that I have water to the heater core.
I've stood there and watched while the engine was running, and the water
ump spun just fine. (Well, the system was full of coolant, so I only know
hat the pulley was spinning. I wasn't directly watching the impeller.) I
evved it up, and there was no hesitation or slipping of the pulley.
I've read an idea about a hose collapsing on the input side of the pump and
estricting the flow, but since there are three of them, I find it hard to
elieve that they would all fail at the same time.
My dad has suggested a head gasket failure and air lock that is stopping it
rom pumping, which seems possible, but I want to remove all other credible
ossibilities before removing the head. I've also dealt with a couple of
hese before that had blown head gaskets, and I've never had one stop
umping like this.
The coolant that came out was pretty ugly black, but not oily. So that
ould seem to give some credibility to a head gasket. I've never noticed it
ook anything other than green before, but it's been so reliable that I
aven't had to mess with it much lately.
So I think that's all the relevant facts. I'm hoping to learn/benefit from
he combined experience and knowledge of this list. I'm kind of at my wits
nd, and with this engine having unknown miles, but I suspect in the
allpark of 400k, I might get in there and decide it needs to be rebuilt.
ith where I am in my life right now, it would be best to be able to wait 6
onths or a year before having to tackle such a big job. So even if I open
t up, I'm going to want to do the bare minimum to get by until I have the
ime to really do it right, if it gets to that.
Thank you everyone!
rik
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