[urq] Cooling System question- update

[Keith]

I don't think there is any doubt now. I went for a short trip to town and 
when I got to town (2 miles) the system was under great pressure. I let it 
cool and then drove home and once it had cooled down again I removed the 
plugs. 2,3,4 & 5 were fine - a little darker than I expected but it had just 
run on rich mixture. No1 plug was black and was really hard to remove due to 
what I found was rust on the thread. Shining a torch down the plug holes - 
revealed 2,3,4 & 5 had a blackish oily film on their surface but nothing too 
bad but No1 was shiny clean aluminium and looked a bit damp. I rolled up a 
piece of newspaper and pushed it in to the plug hole and soaked up some 
drops of liquid which smelled of antifreeze. There's no water in the oil, so 
I'm hoping I've caught all this in time but I guess I'll only know if there 
has been any damage once I strip it down - which I'll start next week once 
I've bought all I need for head gasket change (gaskets, bolts and beer). It 
will be interesting to find what has caused this. The engine is 10 years and 
33000 miles old and despite this trouble runs fine. I reckon the recent and 
occasional odd spots of coolant on the garage floor were overflow from the 
header tank when the pressure got too great. I guess I have been lucky the 
heater matrix didn't fail.
So, off the road for the winter now.......
Thanks to all who answered my appeal for thoughts and guidance. No doubt 
I'll be back on the list if I encounter bad things!
Thanks again and all the best

Keith

'87 WR in darkest foggy Worcestershire.



-----Original Message----- 
From: Chris Miller
Sent: Saturday, October 13, 2012 9:50 PM
To: 'Keith' ; urq at audifans.com
Subject: RE: [urq] Cooling System question

I'd replace the cooling overflow bottle cap if you are concerned about 
pressure in the system; I believe that is the pressure relief valve in the 
cap.

Easy ways to test for the head gasket leak (into the combustion chamber) 
include checking the plugs; the really clean cylinder may be leaking; also 
there are test strips you can use in the coolant to see if there are 
combustion gasses present.

As for possible leaks:

If it is leaking to the outside of the engine, not into the cylinders, I 
think you'd see a stain on the block.   Pull the lower engine cover and see.

The later cars came with an after run electric cooling pump, I believe; not 
sure when that started.  They are plastic and can crack and leak.  Do not 
check them when hot as they can break open and douse you and cause a severe 
burn.  Similarly the control valve for the heater core is plastic and can 
crack.

Another possible spot for a leak is the water pump; sometimes they seep but 
it would be difficult to see with the belt guards in place.

There is also a small tube across the front of the block, behind the inner 
belt guard against the block.  On my 20v motor, it has a rubber hose on each 
end; I think that is the water return feed from the turbo.  The feed is 
below the turbo off the block.

Chris

-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On Behalf 
Of Keith
Sent: Saturday, October 13, 2012 4:27 PM
To: urq at audifans.com
Subject: [urq] Cooling System question

Evening All,
I have some curious goings-on with my quattros cooling system. On occasion 
but not always there are one or two drops of coolant on the garage floor. 
The system does indeed lose a little, but so little as to be unable to trace 
the source. The running temperature is absolutely normal but the cooling 
system remains pressurised even when the engine has cooled right down. The 
engine runs fine.  I have searched on line for possible causes of the system 
remaining pressurised, some suggest a leaking head gasket. Obviously I do 
not want to remove this just to look and there are no other signs that I am 
aware of to suggest HG failure. I will be surprised and not a little 
disappointed if the HG is failing because the block was Wills ringed when I 
built it (10yrs ago though) to ensure a good seal around each cylinder and I 
don;t thrash it (in fact my friend ridicule my mechanical sympathy for my 
car!) I guess the question is: should I be concerned? Are there any tests I 
could do to confirm/deny HG failure given the current minimal outward 
symptoms? The amount of residual pressure in the system when cold is what 
concerns me the most though.
Any ideas/suggestions gratefully received (as always).
Regards
Keith

‘87 WR
_______________________________________________
Audifans urq mailing list
Manage your list connection: http://www.audifans.com/mailman/listinfo/urq
http://www.audifans.com/kb/List_information

Pictures/Polls/Database at: http://autos.groups.yahoo.com/group/urquattro/


-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.2221 / Virus Database: 2441/5329 - Release Date: 10/13/12