[s-cars] ping vs. rattle

[Tom Green]

If you suspect pinging, investigate, and not by checking how long it  
continues while accelerating or
listening to it while revving the engine.  Sure you have knock  
sensors, but are they working? and at
what threshold.  Obviously, if you have detonation long enough for you  
to hear it, something is wrong,
and if you continue to listen to it, something is wrong with you.

A blown head gasket does not always intrude into the coolant  
passages.  This failure between cylinders
can cause significant damage if you don't recognize the problem.    
There is some real BTDT experience
here that you can have for free.

Tom

On Wednesday January 26, 2011, at 12:21 PM,  "Bares, Vittorio" <Vittorio.Bares at nuance.com 
 >   wrote

> Sounds exactly like the symptoms on my S6. Gasket was toast between  
> 4 &
> 5. Head was ok, but as Dave indicates persistent running could not  
> only
> ruin the head but worse the block.
>
> Compression test was sufficient, but leak down further supported the
> findings.
>
> Vittorio -
> -----Original Message-----
> From: s-car-list-bounces at audifans.com
> [mailto:s-car-list-bounces at audifans.com] On Behalf Of  
> djdawson2 at aol.com
> Sent: Wednesday, January 26, 2011 12:07 PM
> To: pmische at att.net; theringmeister at triad.rr.com;
> s-car-list-bounces at audifans.com; jjssmccarthy at yahoo.com;
> s-car-list at audifans.com
> Subject: Re: [s-cars] ping vs. rattle
>
>
> I wouldn't spend any time trying to figure out why the engine isn't
> getting enough fuel, or trying to modify the ignition timing in any  
> way.
> Chances are good that if these parameters were off, you'd have a check
> engine light.
>
> If this sound really is the engine pinging (detonating) under a no- 
> load
> situation... in other words, it isn't some other mechanical noise...
> your headgasket is likely blown between 2 adjacent cylinders.
>
> This is a fairly common failure, and the symptoms are detonation  
> sounds,
> even under no load.  Keep running it, and you'll burn up the cylinder
> head between those cylinders.
>
> If I were you, I'd perform a quick compression check ASAP.  If you  
> find
> 2 adjacent cylinders low, you've got a headgasket problem.  The  
> usual is
> #4 and #5... BTDT.  If your compression is even across all 5, be  
> happy.
>
> Dave