[urq] Cooling System question- update

Tue Oct 23 03:28:30 PDT 2012

Don't forget to have the head machined ( flattend , straightend , shaved ?? 
don't know the exact term in english )
Otherwise there's a good chance the headgasket willl fail again .

And while the head is of anyway , I alway's find it a good time to change
the valve stem seals .

Pat

----- Original Message ----- 
From: "Keith" <spotatashleys at hotmail.com>
To: <urq at audifans.com>
Sent: Monday, October 22, 2012 10:08 PM
Subject: Re: [urq] Cooling System question- update

>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
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