A8 Parts Forum  

Go Back   A8 Parts Forum > A8 D2 > D2 - Engine Bay

D2 - Engine Bay Everything under the bonnet

Reply
 
Thread Tools Display Modes
  #1  
Old 10th September 2012, 01:42 PM
The_Laird's Avatar
The_Laird The_Laird is offline
Senior Member
 
Join Date: Jun 2009
Location: Redmile: Leics, Notts, Lincs border - near Belvoir Castle
Posts: 5,069
Default Stuck spark plug

After a service at A4 Audi (Glagow's independent Audi specialist) it was reported that my number 5 plug is stuck. They had the car in last week to see if a long soak in WD40 might free it, but to no avail.

Next step, they say, is to take the head off and send it to an engineering shop to get it removed. This is going to take days and cost in the region of £300 just to remove and refit the head, plus the engineer shop costs.

Is this a common problem and is there another approach that anyone has had any luck with?
__________________
2002 Final Edition S8. Ebony black with Silver Grey leather and myrtle wood trim.
Current mods: solar sun roof, 20mm rear spacers, 15 mm on front, red brembo callipers, 6k headlights, rear view camera, engine remap, alloy dash dial rings, alloy navi rings, tt/phaeton pedal upgrade, (and custom matching foot rest) dension ipod interface & parrot hands free kit (both fully hidden), av input, tv in motion switched thro' PF switch in blanking plug right of steering column, Audi 'quattro' sill covers, repositioned centre console switches, radio clock, .
Planned mods: auto-dimming rear view mirror, dash cam (as steamship's), fit the ski hatch, refit philips drl's (or maybe not - nope, definitely not - horrible botch!).
Reply With Quote
  #2  
Old 10th September 2012, 02:36 PM
47p2's Avatar
47p2 47p2 is offline
Senior Member
 
Join Date: Jan 2012
Location: Scotland
Posts: 1,666
Default

That's a good price.

Have they tried removing the plug whilst the engine is hot?
__________________
.





Nite Blue 3.0L SE Quattro
Reply With Quote
  #3  
Old 10th September 2012, 02:59 PM
The_Laird's Avatar
The_Laird The_Laird is offline
Senior Member
 
Join Date: Jun 2009
Location: Redmile: Leics, Notts, Lincs border - near Belvoir Castle
Posts: 5,069
Default

I don't know if they've tried it with the engine hot - is that a likely fix? If so, I'll have a go myself. They seem to be terrified of breaking the plug
__________________
2002 Final Edition S8. Ebony black with Silver Grey leather and myrtle wood trim.
Current mods: solar sun roof, 20mm rear spacers, 15 mm on front, red brembo callipers, 6k headlights, rear view camera, engine remap, alloy dash dial rings, alloy navi rings, tt/phaeton pedal upgrade, (and custom matching foot rest) dension ipod interface & parrot hands free kit (both fully hidden), av input, tv in motion switched thro' PF switch in blanking plug right of steering column, Audi 'quattro' sill covers, repositioned centre console switches, radio clock, .
Planned mods: auto-dimming rear view mirror, dash cam (as steamship's), fit the ski hatch, refit philips drl's (or maybe not - nope, definitely not - horrible botch!).
Reply With Quote
  #4  
Old 10th September 2012, 03:04 PM
RanjS8 RanjS8 is offline
Senior Member
 
Join Date: May 2010
Location: Midlands
Posts: 594
Default Spark plugs

The spark plugs can become very seized if they have been there a long time. If the engine isnt misfiring on cylinder 5 I would be tempted to leave it for now.

But if you wanted to try and replace it I would try and get the engine nice and warm and then try to release the spark plug with a long breaker bar....but you want to be careful not to break the spark plug, however u may be unlucky and someone may have cross threaded the spark plug.

The only other option is to remove the head and have it drilled out. But if you are going to have the head removed then you might want to think about renewing the intake manifold gaskets and changing the cambelt at the same time, I wouldnt worry about water pump and thermostat at this moment in time.

Mind you it might be worth thinking when the cambelt change is due cos you would probably be better off removing the head then.

If you do decide to take the head off and sending to a machine shop proves expensive, then I have one in my garage from an AVP engine which is spare.
__________________
01 Audi a8 fl sport - Grey, Bose, Glass Sunroof, S8 grill/mirror covers/wheels, Aftermarket Exhaust, very quick and lots of fun!!!!!....well I gave it one final push on the pedal to hear that v8 growl and then it was off to a new home.....
99 Audi a8 fl - Silver, Black alcantara seat/ S8 grill/side mirror, MFSW, Solar Sunroof, 17" Monoblocks (for that extra cushion of air), Rnsc, Bose.....great motorway cruiser....now gone to a new home
02 Final Edition S8 - Avus Silver, Extended Leather Pack III, Front & Rear Heated Seats, Servo, Blinds, Rear Seat Entairtainment with Playstation, Bose, Bi Xenons.....now gone to a new home
97 PF A8 4.2 quattro sport - Cashmere Grey, Servo, RNS E, Blinds, Bose, 20 Final Edition Alloys, LPG....sold sadly and will be missed
03 S4 V8 Saloon - Misano red, Manual, Milltek, Bose, Xenons, RNS E - Sold as of Feb 2012

Reply With Quote
  #5  
Old 10th September 2012, 03:15 PM
David's8's Avatar
David's8 David's8 is offline
Senior Member
 
Join Date: Jan 2012
Location: Helensburgh, Scotland
Posts: 3,506
Default

I know half-remembered knowledge is more dangerous than ignorance, but the volumetric coefficient of expansion of aluminium is approx. twice that of steel so the head would grip the plug tighter when its hot. i.e. it wont "expand" the hole, it will make it smaller and, as the plug expands, it too will fit tighter in the 'ole. So, according to my theory, you should stuck it in the freezer.....

I am very happy to be proved wrong here
__________________
2002 D2 S8 – Ming Blue, Valcona leather, Vavona wood insert, solar sunroof (to be fitted), Heated rear seats, extended leather pack, 18” Avus, ski hatch, Bose, auto dim rear view mirror, rear blind.

Last edited by David's8; 10th September 2012 at 03:25 PM.
Reply With Quote
  #6  
Old 10th September 2012, 03:57 PM
RanjS8 RanjS8 is offline
Senior Member
 
Join Date: May 2010
Location: Midlands
Posts: 594
Default you are probably right

in which case head off or driving to the arctic are the only options possibly...lol

mgiht not be the same thing but I was once told that the platinum spark plugs get seized in the ford ka engine...could the same thing have happened here??
__________________
01 Audi a8 fl sport - Grey, Bose, Glass Sunroof, S8 grill/mirror covers/wheels, Aftermarket Exhaust, very quick and lots of fun!!!!!....well I gave it one final push on the pedal to hear that v8 growl and then it was off to a new home.....
99 Audi a8 fl - Silver, Black alcantara seat/ S8 grill/side mirror, MFSW, Solar Sunroof, 17" Monoblocks (for that extra cushion of air), Rnsc, Bose.....great motorway cruiser....now gone to a new home
02 Final Edition S8 - Avus Silver, Extended Leather Pack III, Front & Rear Heated Seats, Servo, Blinds, Rear Seat Entairtainment with Playstation, Bose, Bi Xenons.....now gone to a new home
97 PF A8 4.2 quattro sport - Cashmere Grey, Servo, RNS E, Blinds, Bose, 20 Final Edition Alloys, LPG....sold sadly and will be missed
03 S4 V8 Saloon - Misano red, Manual, Milltek, Bose, Xenons, RNS E - Sold as of Feb 2012

Reply With Quote
  #7  
Old 10th September 2012, 05:29 PM
Dezzy's Avatar
Dezzy Dezzy is offline
Senior Member
 
Join Date: Sep 2009
Location: N. Devon
Posts: 2,715
Default

I replaced mine not so long ago and a few of them were really tight. In the bottom of the spark plug recess was black tar like stuff, i'm not sure if this made things worse or even how long the plugs had been in there. 8's a 96 and the plugs had Audi rings on them so who knows.

If you're going for it use a T bar to get evenish pressure if you can.

Also all that WD and sh it in the hole will now go into the hole when you do get the plug out, if petrol and gas don't come out under pressure WD isn't going in just being sprayed in there.
__________________
1996 A8 4.2 QS. Bose, Solar roof, um...um... rally sport towbar. Now gone to a new home as the Traders 8.

Bright yellow bus o love.
Reply With Quote
  #8  
Old 10th September 2012, 05:40 PM
ainarssems ainarssems is offline
Senior Member
 
Join Date: Aug 2010
Location: Rushden, Northants
Posts: 3,799
Default

Quote:
Originally Posted by David's8 View Post
I know half-remembered knowledge is more dangerous than ignorance, but the volumetric coefficient of expansion of aluminium is approx. twice that of steel so the head would grip the plug tighter when its hot. i.e. it wont "expand" the hole, it will make it smaller and, as the plug expands, it too will fit tighter in the 'ole. So, according to my theory, you should stuck it in the freezer.....

I am very happy to be proved wrong here
No the hole expands as well. For example on suspension arms when you try to press out bushes aluminium arms need less heating to get them out then steel/cast iron arms as aluminium expands less.

You can also try to freeze the plug itself using something like plumbers pipe freeze.

Or just attack with brute force and if it brakes or damages thread just drill it out and put a sleeve in. I think damaged thread repair with sleeve costs around £60. They just turn engine to position where valves are closed for that cylinder, drill out a hole, rethread it with bigger thread, blow out shavings with compressed air and put in sleeve with new plug.

If the old plug is not giving any running problems might as well leave it there.
__________________
Currently 8less
2011 Q7 S Line 3.0TDI, 2016 Tesla Model S 90D

8 history:
2006 A8 Sport 4.2TDI quattro SOLD,
1997 S8, reached end of life with gearbox failure
Reply With Quote
  #9  
Old 10th September 2012, 07:11 PM
Conan_the_Librarian's Avatar
Conan_the_Librarian Conan_the_Librarian is offline
UberSeniorChiefLibrarian
 
Join Date: Jan 2009
Location: In a library
Posts: 3,860
Default

I agree with ainarssems. Don't worry about it until its an issue. When it is an issue, go down the brute force root. Make sure you use a 6 sided plug spanner for maximum grip and a long breaker bar to exert torque slowly. If it snaps, get that cylinder to top dead centre on the compression Stroke (valves both closed) And get a piece of wood dowel the same size as the plug housing and drill a 4mm hole to start with in it with a pillar drill. You now have you drill guide. Measure the amount of plug left in the hole, mark you drill bit so you don't drill to far ( preferably not as far as the electrode) and steadily increase the size of the bit until about 10mm, then try a stud extractor. If that fails, continue drilling until you drill out the plug and the heli coil blow out any swarfe, vacume out the swarf, then blow out the swarfe and reasemble.
__________________
Conan (the Librarian)

Watch it if you dare

Currently,
2000 S8, Merlin Purple, Leather Pack 1, Winter Pack 1, SPAX adjustable suspension, AP Racing 6 pot front caliper, 385mm fully floating disks, EBC Yellow Stuff Pads, Black Diamond grooved rear disks and predetor pads, D2 Doctors Brake Block.
1997 4.2 A8SQ - the Projekt. 12 years and ongoing!
1997 4.2 A8SQ - Ming Blue. Restoration sat waiting; saved from the Scrapyard
2003 C5 Allroad 4.2Q - Cobolt Blue. Towing car. Laid up awaiting manual conversion.
2005 C5 Allroad 2.5TDi FE - Grey - Workhorse.
2015 Q3QS SLine - Daytona Grey. Lots of extras! Long Haired Admirals cutter.

Previously
2003 C5 A6 1.9TDI FWD - Loaner from D2 Doctor Lifex
1997 S8 - Ming Blue. Loaned out and written off. I loved that car. My first engine swap after cambelt failure.
1996 4.2 A8SQ - Ming Blue. 178k on a cambelt! Trader's 8. Delivered to A8Parts at Lifex.
2003 2.8 A8SQ - powder blueish. Fill in for a while. Sold on.
1998 1.8T A4 Avant FWD. Ming Blue (there's a theme here), PEX for the 97 S8.
And a list of non VAG going back 40 years before I saw the light.
Reply With Quote
  #10  
Old 11th September 2012, 07:23 AM
sloss's Avatar
sloss sloss is offline
Senior Member
 
Join Date: Jan 2009
Location: Aberdeen
Posts: 505
Default

As Ainarssems and Conan say....

All I'd add and I know it sounds silly but try tightening it a tad first then slacken. Back and forward a bit until if feels like it'll come out.

Although if it ain't broke why fix it

Stew,
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 01:09 AM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.