Blown Head Gasket (was:Power loss and white smoke)
fairbanks at cmu.edu
Fri Apr 14 10:39:26 EDT 2006
This is turning into a mystery.
The mechanic is "99% confident" that my head gasket is ok. His
technique is to use his emissions machine to sniff for hydrocarbons in
the coolant. He did this while the car was cold and again when it was
warmed up. In neither case did he find hydrocarbons in the coolant.
Here are the "facts":
- I saw light colored smoke (whitish, I think) after starting my car
Sunday. This was after a hard acceleration run where I heard a grunk noise.
- The emissions machine didn't detect hydrocarbons in my coolant
- The coolant level is a couple inches lower than it was last week
- The thermostat was replaced last week and the coolant topped off (not
flushed and replaced)
- We've been watching the turbo seals for more than a year since they
seem to be leaking a bit of oil. There is some oil in the intake hose.
Theory #1: It really is a head gasket problem. The coolant level
dropped because the coolant was burned and that created the white smoke
I saw (a single time) on Sunday. The gasket is not leaking right now,
and made it on a 240 mile road trip after the smoke, but could fail
Theory #2: It is the turbo seals that are leaking. The white smoke I
saw was actually pale blue and was oil burning. The drop in coolant is
explained by an air bubble in the coolant -- the thermostat was replaced
last week. The grunk noise could be the turbo.
I'd prefer if theory #2 is correct but, after all of your dire warnings,
I want to be sure it isn't theory #1. Is the technique of using the
emissions machine to sniff the coolant effective?
Thanks again for all of your on- and off-list help.
PS For those of you in an upgrade mood (fat wallet syndrome?) there is
a one-owner 1995 S6 Avant for sale in Denver on Craigslist.
Kenneth Keith wrote:
> The standard "paper" style head gasket has apparently been superceded
> by the metal one, which was supposedly introduced with the ur-S6.
> Here's a gasket set with it, including a picture of the metal gasket.
> It's a multi-layer steel gasket. There are also aftermarket solid
> copper gaskets, but I doubt people are referring to that, and I would
> go with stock if I were in your shoes. If it were me, I might send
> the head off to be ported since you're in there. Sounds like you just
> want to fix the problem and get back on the road, however.
> While the head is off, you should probably have a valve job done,
> which would replace those valve stem seals mentioned earlier, among
> other things.
> Do you have an RS2 exhaust manifold? Doing the head gasket would be a
> great time to put one on, as it's a PITA to install them in place.
> There would be no better time than when it is already down and apart.
> Another thing you can do while it's apart is put a metal distributor
> gear on, if it doesn't already have one. There's a guy on Ebay that
> sells them.
> On 4/11/06, George Fairbanks <fairbanks at cmu.edu> wrote:
>> If indeed it is a blown head gasket, what do I need to tell my mechanic
>> about our cars specifically?
>> - A couple people have recommended using a metal gasket instead of the
>> stock paper one -- is this an Audi part that replaces the old one or an
>> aftermarket upgrade?
>> - The old postings on the topic indicate that the motor mounts are
>> easy to change at this point and I'd be happy to have those replaced too.
>> - Anything else while it's all apart?
>> - Or any gotchas for him to look out for?
>> I know a lot of us have cars with around 200k miles and a fair number of
>> them are chipped. I hope this won't be an increasingly common topic on
>> the list. I've had no serious problems until now and have been super
>> happy with the car's reliability. And I don't get to drive the car hard
>> except for about once every three months.
>> Regarding the questions about the grunk noise and power loss, it was
>> more like a hesitation or dip in power, not an cutoff.
>> Consider me admonished for driving the car after the white smoke. Off
>> list, Doug sent me these scary pictures:
>>> Ahh, here we go: http://www.motorgeek.com/phpBB2/viewtopic.php?t=5155
>>> and http://forums.audiworld.com/v8/msgs/79567.phtml Now, these are
>>> only the 10valve motors, but the same theory applies. Sorry if I
>>> scared you too much.
>> Thanks again for all of your helpful responses,
>> Ben Swann wrote:
>>> You have a head gastket leak. I've seen this before and although the car
>>> seems to run fine now, at some point things will blow catastrophically. You
>>> have been lucky so far. The extra pressure on the system will likely blow a
>>> few things out and everything goes down hill quickly - busted open heater
>>> valve, blown hoses, and last but not least - warped head! All of this will
>>> happen at once when engine is hot and the rapid loss of coolant will do
>>> Don't take any more chances, tow it to someone who will do the job if you
>>> can't and get it fixed before it goes critical!
>>> You should probably have the head pulled and checked as there may already be
>>> a problem. No need to have the job done twice.
>>> benswann at comcast.net
>>> 83 urq, / =oooo= \ alpine and Inga
>>> '90 Coupe Quattro (==\ oooo /==) ES2 Conversion
>>> 91 200qa20v, [ =!\=oooo=/!= ] avant and sedan
>>> [Date: Tue, 11 Apr 2006 10:09:59 -0400
>>> From: George Fairbanks <fairbanks at cmu.edu>
>>> Subject: Re: Power loss and white smoke
>>> To: Peter Schulz <pcschulz at comcast.net>
>>> Cc: 200q20V mailing list <200q20v at audifans.com>
>>> Message-ID: <443BB8B7.2020000 at cmu.edu>
>>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>> I've checked the coolant this morning and the level is low (it was full
>>> Thursday) and it looks dark. Since I didn't check it earlier, I don't
>>> know if my 240 mile drive Sunday evening (where the car was driving
>>> fine) contributed to the decline, or if it was a one-time leak. It's
>>> weird that I haven't seen any smoke since that first time Sunday at noon.
>>> I started up the car this morning and the exhaust is clean and I'm not
>>> seeing any bubbles in the coolant tank. I've made an appointment for my
>>> mechanic to look at it tomorrow.
>>> Looking through the archives it seems that a couple other listers have
>>> replaced their head gaskets. I'm not completely without mechanical
>>> skills but doing a head gasket myself is not going to happen. The car
>>> has been running great otherwise and I'm hoping that even if it needs a
>>> head gasket I can justify the price.
>>> Thank you all for your help,
>>> Peter Schulz wrote:
>>>> IMHO, I would not agree with Bernie about the longetivity of the
>>>> headgasket, especially the non metal ones..
>>>> Over time and multiple previous owners, who can ensure that the head
>>>> has not overheated? Are you going to trust the MFTS? LOL
>>>> Increased boost pressure with an upgraded cheap can reduce a
>>>> compromised headgasket's life even further...
>>>> Audi eventually went to a metal headgasket, but I still observed that
>>>> as late as 1995 they still used the paper type ones on the S6 AAN motor.
>>>> I've observed a number of failures first and second hand...ask my
>>>> friend Ray Tomlinson....
>>>> At 11:17 PM 4/10/2006, Bernie Benz wrote:
>>>>> My post copies are not going to the list, so if you wish to repost this
>>>>> list FYI, OK.
>>>>> IMO, I5 head gaskets are bullet proof and not age dependent, unless the
>>>>> engine has been overheated enough to warp the head, which can cause
>>>>> immediate failure unless the head has been planed.
>>>> -Peter Schulz
>>>> Chelmsford Ma, USA]
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