[s-cars] Warped Head Symptoms?

[djdawson2 at aol.com]

If your head is warped, there will be only one symptom, and that will be eventual head gasket failure.

In 20v Audi engines, I've experienced headgasket failures of just 2 types:

- #1 Blown between a cylinder and the cooling jacket.  This often results in blowing the seal between the plastic ends caps and the aluminum radiator core, blowing off the coolant res cap, blowing your heater core, etc...  This version of headgasket failure is relatively harmless in the big picture - symptom is simply excessive cooling system pressure.  Fail to grasp what is going on, and you'll just be replacing each weak link in your cooling system, one at a time, that succumbs to the excess pressure.

- #2 Blown between cylinders 4 and 5.  This results in a cross ignition situation.  Cylinder 4 fires right before 5 (1-2-4-5-3).  When 4 fires, the flame travels across to cylinder 5, preigniting it.  Result is losing a lot of aluminum from the head between the cylinders, and a destroyed #5 piston/cylinder resulting from preignition and detonation.  Fail to recognize this situation quickly, is costly... you can pretty much count on having to replace the block and head assemblies.  If your car EVER starts to sound like it's "pinging" all the time, even at idle, a headgasket blown between 4 and 5 is the likely culprit.  If you catch it fast, you'll be very glad you did.  Fail to - get out your wallet.

Back to your t-stat.  I'm sure there are stories of t-stats failing closed that someone can and probably will tell us.  But in my 30-ish years of dozens of Audi/VW/BMW cars, I have yet to personally experience a t-stat that failed in the closed position.  EVERY t-stat failure I've ever had became evident as soon as it got cold out.  They would fail in the open position, and in cold weather the engine would run too cool, and provide poor heat.  My point?  There are a number of reasons you could have blown your coolant.  However, I seriously doubt it was because of your t-stat.  I would first check to make sure your fans are coming on, etc... to insure the car isn't overheating in general.  All the while, I'd be wary of any signs that the real issue is pressure being leaked into the cooling system from combustion.

hth

Dave

 

 

 

-----Original Message-----
From: Tony Curran <tony.curran at sympatico.ca>
To: S-Car-List at Audifans.Com <s-car-list at audifans.com>
Sent: Sun, Jan 5, 2014 1:26 am
Subject: [s-cars] Warped Head Symptoms?


Hi All,

 

On another thread there was mention of loss of coolant and possible warping
of the head due to overheating.

 

My S6 experienced loss of coolant recently - blew it out through the
overflow tank cap. It appears that the thermostat was the culprit. There
were no telltale head gasket failure signs.

 

So, if the engine did overheat sufficiently to warp the head, what would the
symptoms be?

 

Also, when I ordered thermostat from local online source, this is the part
that arrived.

 

http://www.calorstatbyvernet.fr/CATALOGUE/Accueil/IBEAALTHSnpGUkN0aVVUSHRFAA
A?A8

 

It is somewhat different to the Wahler brand.

 

TIA

 

Tony

96 S6

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