Help, Overheating.

Volkswagen CL Umwelt TD Estate. 1.9 AAZ engine 1998 S reg.

Emptied cooling system yesterday. Refilled using the recommended antifreeze.
Today after driving around 15 miles the car overheated, smoke from bonnet,
kind of burning smell. Shut off straight away and called the RAC, they
arrived after about 45 minutes by which time things had cooled down. He said
he wasn't sure but thinks it may be the water pump. He told us to drive home
(about half a mile) slowly and switch off at traffic lights etc. he followed
us, just as we got home the temp guage shot to 90 (no smoke this time but
faint smell)

The main thing I was wondering was could it be an air lock instead of the
water pump, top and bottom hoses seem at the correct temp (bottom one cooler
than top, but still pretty warm) the fans did kick in and off again after we
refilled at the coolent change, but I don't think it took in as much water
as it should. This being the first Volkswagen I have owned, previous cars
having had bleeders.

Any advice would be greatly appreciated,
thanks,
Mandie.

The main thing I was wondering was could it be an air lock instead of the
water pump, top and bottom hoses seem at the correct temp (bottom one cooler
than top, but still pretty warm) the fans did kick in and off again after we
refilled at the coolent change, but I don't think it took in as much water
as it should. This being the first Volkswagen I have owned, previous cars
having had bleeders.

Was the coolant tank full after all this, or had the level dropped?
Usually, if there's a bubble in the system, it'll work itself out and
the coolant in the tank will suddenly suck down into the system when the
thermostat opens, at the latest. If the coolant level stayed the same,
then the pump is as good a suspect as any. It would be quite a
coincidence, but VW water pumps do have a history of frequent failure.

Was the coolant tank full after all this, or had the level dropped?
Usually, if there's a bubble in the system, it'll work itself out and the
coolant in the tank will suddenly suck down into the system when the
thermostat opens, at the latest. If the coolant level stayed the same,
then the pump is as good a suspect as any. It would be quite a
coincidence, but VW water pumps do have a history of frequent failure.

Thanks for your reply,
The tank stayed pretty much the same,
Guess the gunk of the old coolent mix was holding it together :-)
Any tips on putting a new pump in?

Did you refill with the recommended quantity? If the book shows a
capacity of 5 liters and you only installed 3 liters then you could of
had a heck of a big bubble of air. I try to measure waht I put in so I
can guess f I have abig bubble that needs to be bled somehow. The old
Rabbits/Golfs required a variety of tricks to get the air out of the
system. Basically I recall it as the removal of a hose to dump
antifreeze in. My 2003 tdi did not seem to require any burping but
maybe I forgot a burping after I replaced the water pump. I do keep
the cap off the resevoir to watch how the water is flowing. On a
vehicle that has a cap on the top of the radiator I watch for burps
and siginificant drops in antifreeze level before I drive it anywhere.
Once again measuring things as I go if i have drained the block and
replaced the water pump.

Another thing I do is catch the old antifreeze in a catch pan. I dump
it in to old water or soda bottles. 3 liters out then 3 liters in.

On Thu, 3 May 2007 03:09:27 +0100, "Mandie @k@ Zepherous"
<shpams (AT) gmail (DOT) com> wrote:

Volkswagen CL Umwelt TD Estate. 1.9 AAZ engine 1998 S reg.

Emptied cooling system yesterday. Refilled using the recommended antifreeze.
Today after driving around 15 miles the car overheated, smoke from bonnet,
kind of burning smell. Shut off straight away and called the RAC, they
arrived after about 45 minutes by which time things had cooled down. He said
he wasn't sure but thinks it may be the water pump. He told us to drive home
(about half a mile) slowly and switch off at traffic lights etc. he followed
us, just as we got home the temp guage shot to 90 (no smoke this time but
faint smell)

The main thing I was wondering was could it be an air lock instead of the
water pump, top and bottom hoses seem at the correct temp (bottom one cooler
than top, but still pretty warm) the fans did kick in and off again after we
refilled at the coolent change, but I don't think it took in as much water
as it should. This being the first Volkswagen I have owned, previous cars
having had bleeders.

Any advice would be greatly appreciated,
thanks,
Mandie.

Was the coolant tank full after all this, or had the level dropped?
Usually, if there's a bubble in the system, it'll work itself out and the
coolant in the tank will suddenly suck down into the system when the
thermostat opens, at the latest. If the coolant level stayed the same,
then the pump is as good a suspect as any. It would be quite a
coincidence, but VW water pumps do have a history of frequent failure.

Thanks for your reply,
The tank stayed pretty much the same,
Guess the gunk of the old coolent mix was holding it together :-)
Any tips on putting a new pump in?

Well, just because the coolant level didn't suck down, it's not
conclusive that you need a new pump, it's just a statistical likelihood.
It could still be a big airlock, but I haven't had a problem with that
in my newer VWs, they've been good for me about taking coolant. On my
old one, I used to take the upper hose off the radiator and pour coolant
into it, to get the block filled. It would not take coolant through the
overflow tank very well at all. While it's true that VW water pumps are
unreliable, I'd also hate to see you jump to the wrong conclusion based
on that fact alone. Can you tell if there's coolant in the top hose?
Maybe pull it to verify, and pour coolant directly into the hose.

I'm not familiar with the 1.9 AAZ engine, but if it's a design that
drives the water pump from the timing belt, then go ahead and replace
the timing belt and tensioner at the same time.

Thanks for your reply,
Stupidly we never filled from a measured water can, we just topped up until
it would take no more.
I got a water pump and timing belt today and we will fit them tommorrow,
Definatly using a container that will let us know how much goes in.

"Jim Behning" <jimbehning (AT) doesthisblockpork (DOT) mindspring.com> wrote

Did you refill with the recommended quantity? If the book shows a
capacity of 5 liters and you only installed 3 liters then you could of
had a heck of a big bubble of air. I try to measure waht I put in so I
can guess f I have abig bubble that needs to be bled somehow. The old
Rabbits/Golfs required a variety of tricks to get the air out of the
system. Basically I recall it as the removal of a hose to dump
antifreeze in. My 2003 tdi did not seem to require any burping but
maybe I forgot a burping after I replaced the water pump. I do keep
the cap off the resevoir to watch how the water is flowing. On a
vehicle that has a cap on the top of the radiator I watch for burps
and siginificant drops in antifreeze level before I drive it anywhere.
Once again measuring things as I go if i have drained the block and
replaced the water pump.

Another thing I do is catch the old antifreeze in a catch pan. I dump
it in to old water or soda bottles. 3 liters out then 3 liters in.

On Thu, 3 May 2007 03:09:27 +0100, "Mandie @k@ Zepherous"
shpams (AT) gmail (DOT) com> wrote:

Volkswagen CL Umwelt TD Estate. 1.9 AAZ engine 1998 S reg.

Emptied cooling system yesterday. Refilled using the recommended
antifreeze.
Today after driving around 15 miles the car overheated, smoke from bonnet,
kind of burning smell. Shut off straight away and called the RAC, they
arrived after about 45 minutes by which time things had cooled down. He
said
he wasn't sure but thinks it may be the water pump. He told us to drive
home
(about half a mile) slowly and switch off at traffic lights etc. he
followed
us, just as we got home the temp guage shot to 90 (no smoke this time but
faint smell)

The main thing I was wondering was could it be an air lock instead of the
water pump, top and bottom hoses seem at the correct temp (bottom one
cooler
than top, but still pretty warm) the fans did kick in and off again after
we
refilled at the coolent change, but I don't think it took in as much water
as it should. This being the first Volkswagen I have owned, previous cars
having had bleeders.

Any advice would be greatly appreciated,
thanks,
Mandie.

Well, just because the coolant level didn't suck down, it's not
conclusive that you need a new pump, it's just a statistical likelihood.
It could still be a big airlock, but I haven't had a problem with that in
my newer VWs, they've been good for me about taking coolant. On my old
one, I used to take the upper hose off the radiator and pour coolant into
it, to get the block filled. It would not take coolant through the
overflow tank very well at all. While it's true that VW water pumps are
unreliable, I'd also hate to see you jump to the wrong conclusion based on
that fact alone. Can you tell if there's coolant in the top hose? Maybe
pull it to verify, and pour coolant directly into the hose.

I'm not familiar with the 1.9 AAZ engine, but if it's a design that drives
the water pump from the timing belt, then go ahead and replace the timing
belt and tensioner at the same time.

I got a pump and timing belt earlier, (amazed at how fragile the pump looks
compared to my partners
Cavalier.
We can not get time to work on the car today, but will get it done
tommorrow.
I will check the top hose before starting any work on it.
The timing belt and tensioner was changed less than1000 miles ago which was
in December,
the car is mainly used for local driving for my disabled Mum (her scooter
fits in the back)
would the tensioner need to be changed again?
The car has 184000 on the clock and I have no idea when the pump was fitted,
if it is the pump that's taught me a lesson, should have done it along with
the timing belt and
tensioner :-)

The timing belt and tensioner was changed less than1000 miles ago which was
in December,

Scanning the parts catalogs quickly, it looks to me that the AAZ engine
does not drive the water pump off the timing belt, the pump is nothing
like the ones on the engines that run off the timing belt. So your
recent work probably has no bearing on your current problem. That's the
good news, I guess.

"Brian Running" <brunning (AT) XXameritechXX (DOT) net> wrote

The timing belt and tensioner was changed less than1000 miles ago which
was in December,

Scanning the parts catalogs quickly, it looks to me that the AAZ engine
does not drive the water pump off the timing belt, the pump is nothing
like the ones on the engines that run off the timing belt. So your recent
work probably has no bearing on your current problem. That's the good
news, I guess.

I was relieved to find that today. I put a new water pump in, have to say
the old one didn't seem
too bad, just a little bit stiffer to turn with a very gentle touch, about
the same with normal. The impellers were whole.
Put a new timing belt on seeing as I had to remove the other one to get to
the water pump.
Put it all back together and started filling the cooling system, this time I
removed the top hose and filled through there as well,
it took a bit more water and coolant this time round. The heater blew hot
and the fans kicked in and back off
(they did this last time as well though) I ran out of time to put the belly
pan on and I haven't taken it for a run yet, I will do
this tommorrow. The temperature goes to 90 and stays there, it done that
last time and gave no indication gauge wize and gave no warning lights
to let us know it was going to overheat, the smoke and burning smell was
what gave it away :-(
On a rough guess I would say the job should have taked around 2 hours, it
only took me 7.5 hours.

Doh... forgot to mention I had a flat bettery in the week, and today after
running the car for quite a while I went to
turn the ignition and flat again.
Seeing as it's the fan belt that drives the water pump thought it would be
of some significance, the belt did not seem slack.