Audi Parts Catalog Audi Accessories Catalog Audi Technical Articles VW-Audi Tech Forums
 
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
VW / Audi Spark Plug Replacement
 
Bookmark and Share

Pelican Technical Article:

VW / Audi Spark Plug Replacement

Peter Bodensteiner

Time:

2 hours2 hrs

Tab:

$25

Talent:

***

Tools:

10mm wrench, spark plug socket, 5mm Allen wrench

Applicable Models:

 
Audi A4 (1997-01)
Audi A4 Quattro (1997-01)
Audi TT (2000-04)
Audi TT Quattro (2000-04)
VW Beetle (1999-02)
VW Golf (2000-02)
VW Jetta (2000-02)
VW Passat (1996-00)

Parts Required:

New spark plugs

Hot Tip:

Always change plugs with the engine COLD.

Performance Gain:

Better MPG

Complementary Modification:

Change Air Filter

Changing spark plugs is one of those time-honored maintenance tasks that any self-respecting car enthusiast should do themselves. It's usually easy to do and it gives you a chance to feel like a real gearhead without having to get all that dirty or spend hours writhing around on the floor of your garage.

Granted, some of today's cars are packaged so tightly that it can be very difficult to reach the plugs, and some modern cars have extremely long recommended service intervals for spark plugs, further decreasing the incentive to DIY.

In the case of the 1.8T engine in the A4, however, it's quite easy to change the spark plugs. That's a good thing, because turbocharged engines tend to be harder on spark plugs, particularly when increasing the boost and/or tinkering with air-fuel ratios after performance upgrades. In addition, if your turbocharged engine isn't running quite right, it is quick and relatively inexpensive to eliminate the spark plugs as a potential source of the problem through a plug change.

The 1.8T has a coil-on-plug ignition system. All this means for the home mechanic is that the coil must be removed in order to access the spark plugs, rather than a cable running between the coil, or the distributor, and the spark plugs. Removing the coils and/or the spark plugs is necessary for some other projects, such as the timing belt change and replacing the valve cover gasket.

One other thing you may want to consider is putting a small amount of dielectric grease on the ends of the coil pack where it attaches to the spark plug. Dielectric grease helps to keep the rubber boots from drying up and cracking. When the rubber boots crack, they can leak voltage out. Additionally, many Audis have had the coil packs replaced due to a factory recall. You may want to call your local Audi or VW dealer with your VIN number to see if the coil packs have already been changed.

Any time you're working on electrical components of a vehicle, you should disconnect the battery at the negative terminal to help prevent any short circuits.
Figure 1

Any time you're working on electrical components of a vehicle, you should disconnect the battery at the negative terminal to help prevent any short circuits. This battery is marked with a "-" minus symbol at the negative terminal. The battery cable clamp has a 10mm nut.

Each spark plug coil is equipped with an electrical connector like this one.
Figure 2

Each spark plug coil is equipped with an electrical connector like this one. You might be able to remove all of the coils without disconnecting them from the wiring, but the job is a bit easier if you disconnect them. Insert a flat-blade screwdriver as illustrated and tilt it toward horizontal while you wiggle the connector off of the coil.

Here's a look at the connector as it is being removed.
Figure 3

Here's a look at the connector as it is being removed. Note the small raised notch on the coil side of the connector - when you use the screwdriver in the previous photo, you're lifting a portion of the connector over this notch to release it.

You can use a second screwdriver to help push the connector away from the coil while you lift the clip inside the connector over the securing notch.
Figure 4

You can use a second screwdriver to help push the connector away from the coil while you lift the clip inside the connector over the securing notch. Note that the wiring behind the connector can press against the lip of the valve cover behind it while you're trying to the connector off of the coil.

There are plastic clips that secure the wiring as it runs along the top of the valve cover.
Figure 5

There are plastic clips that secure the wiring as it runs along the top of the valve cover. You can open these to free up the wiring, or the clips may be loose enough that you can simply lift them straight up and out of the holes in the valve cover into which they are inserted. If you're planning to move the wiring around a lot, it's a good idea to label the wires so that you can reconnect them to the correct coils during installation.

Use a 5mm Allen wrench or socket to loosen the two bolts that secure each coil in place.
Figure 6

Use a 5mm Allen wrench or socket to loosen the two bolts that secure each coil in place.

Clean the area around the coil to prevent any debris from falling into the spark plug well and then lift the coil upward.
Figure 7

Clean the area around the coil to prevent any debris from falling into the spark plug well and then lift the coil upward. It is only held in place by its grip on the spark plug at this point.

This view shows the coil as it lifts off of the spark plug.
Figure 8

This view shows the coil as it lifts off of the spark plug.

Use an extension and a 5/8 spark plug socket to remove the plug.
Figure 9

Use an extension and a 5/8" spark plug socket to remove the plug. This kind of socket usually has rubber or another soft material on the inside to protect the porcelain insulator of the plug and to grip the plug during installation and removal.

Remove the plug from the engine and take a look at it.
Figure 10

Remove the plug from the engine and take a look at it. Racers often "read" spark plugs to determine the health of an engine, but this is best done right after a hot run, and is outside of the scope of this article. For a street car, the plugs should be a medium brown color, and of course all the components of each plug should be intact. An overly oily residue or white flecks would be a cause for concern, indicating incorrect tuning or detonation.

Take each new plug out of its packaging and set the gap between the ground strap and the electrode.
Figure 11

Take each new plug out of its packaging and set the gap between the ground strap and the electrode. This spark plug gapping tool uses a series of different-sized feelers to help you determine how big the gap is. A good gap for a stock 1.8T is .032"; a high-boost engine will need a smaller gap, around .028", which helps the spark cross the gap when operating in a higher-pressure environment. Use the tool to bend the ground strap to create the proper gap, but don't lever it against the electrode, as this can damage it.

Put the new plug into your spark plug socket with the extension attached.
Figure 12

Put the new plug into your spark plug socket with the extension attached. Some sources recommend using an anti-seize compound to the upper threads of the spark plug, while others recommend against. Whichever you choose, now is the time.

Perhaps the greatest fear of anyone installing spark plugs is that they might become cross-threaded, messing up the threads in the cylinder head.
Figure 13

Perhaps the greatest fear of anyone installing spark plugs is that they might become cross-threaded, messing up the threads in the cylinder head. My solution to this is to make sure the plug is secured in the socket, use the extension to ensure that the plug remains perfectly perpendicular to the threads in the cylinder head, and then to tighten the as far as possible by hand, backing out if I feel any undue resistance. The threads, given their location deep within the engine, are unlikely to be gritty or corroded, so you should be able to hand-tighten them almost all the way to tight.

This set of instructions on the side of the spark plug box illustrates all of the above.
Figure 14

This set of instructions on the side of the spark plug box illustrates all of the above. Note the different tightening instructions depending on the shape of the plug-head interface. Essentially you want to hand-tighten the plug as much as you can and then tighten it an additional amount. These plugs look like the ones on the right, so I tightened them an additional 1/2 to 2/3 of a turn.

Again, use the wrench only for final tightening.
Figure 15

Again, use the wrench only for final tightening. If you would rather use a torque wrench, the desired spec is 22 ft/lbs.

The new plugs are installed and now it's time to put the coils in place.
Figure 16

The new plugs are installed and now it's time to put the coils in place. You can do all the plugs at once or all at one time - your preference.

Place the coils onto the spark plugs and settle them down so that they rest on the valve cover.
Figure 17

Place the coils onto the spark plugs and settle them down so that they rest on the valve cover. You can tighten down the Allen bolts most of the way by hand, and then snug them down with a wrench, but not too tight.

Reconnect the wiring to the coils and make sure that any wires you moved out of place have been put back in their proper locations.
Figure 18

Reconnect the wiring to the coils and make sure that any wires you moved out of place have been put back in their proper locations.

Bookmark and Share
Comments and Suggestions:
murphy Comments: Types of plugs to put in 1.8t 2001 Vw
July 31, 2016
  Followup from the Pelican Staff: See this page:

http://www.pelicanparts.com/cgi-bin/supertech/catalog.cgi?action=frameset&return-url=/cgi-bin/supertech/catalog.cgi%3Faction%3Dframeback%26page%3D106&catalog-url=http%3A%2F%2Fwww.pelicanparts.com%2Fcatalog%2FSuperCat%2F2200%2FVAG_2200_ELIGNT_pg1.htm %3Futm_source%3DSuperTech%23item0- Nick at Pelican Parts
 
Carlos Comments: hi i would like to know why the engine ligth is on ?why and what can be the reason and how to find out what is the problem ???volkwagen sport 2001 turbo 1,8
thank you very much
Carlos
October 26, 2015
  Followup from the Pelican Staff: I would start by checking the DME for fault codes. When a fault code is set, the engine light comes on. This will be your best bet when diagnosing.
- Nick at Pelican Parts
 
Flash Comments: Hi and thanks for the straight forward instruction for spark plug replacement for my 2001 Audi A4 B5 1.8t quattro. My diagnostic code reads that I have a mis 1 on 3. I imagine this to be caused by an ignition coil and I want to replace it i prefer genuine parts, which can be expensive, so I found a donor car with a blown engine. Is it possible to reuse the factory ignition coils? What determines if they are good or bad? Also, I noticed that one of the ignition coils is aftermarket and there was oil in the spark plug bay. What is the cause and effect of oil in the spark plug bay? I look forward to your reply and I thank you in advance.
October 16, 2015
  Followup from the Pelican Staff: Spark Kv determines if a coil is good or bad. Either they make enough voltage to fire cylinder, or not. Oil in the hole is from a leaking valve cover gasket.- Nick at Pelican Parts  
BriCo Comments: Hi, I have a misfire on my 2002 Audi TT 1.8L. Plugs are 1000 miles new so replaced coil packs with 4 new. Engine turns over, but won't start. Put old coil packs back in, but same deal turns over but won't start. Ideas?
September 16, 2015
  Followup from the Pelican Staff: I can't help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and fuel pressure, volume, quality and engine compression. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
 
John Comments: While replacing the spark plugs on my 2004 TT 1.8T Quatro, the small "S" shaped tube connected to the airbox hose cracked at the end while moving the airbox out of the way. It appears to be a hard plastic material. I still was able to connect the airhose to the end, but I would like to order another tube. Do you know what part number it is? Many thanks!
September 14, 2015
  Followup from the Pelican Staff: I’m not the best with part numbers.

Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
bless647 Comments: Can I switch the whole harnest to a 3pin plug in??
February 13, 2015
  Followup from the Pelican Staff: I don't believe so. You will have to use what your vehicle was manufactured with, unless there has been an update to the wiring harness by the manufacturer. - Nick at Pelican Parts  
bless647 Comments: Can I switch a 4plug connector ignition coil harnest to a 3plug connector would switch the harnest connector effect the computer system...taking the connectors from the second air filter and connecting a a 3plug compact harnest?? I have new coil packs and there 3pin and it came with a new ignition coil harnest I wanna know if I could switch it with out damaging the car please help
February 13, 2015
  Followup from the Pelican Staff: I don't believe so. You will have to use what your vehicle was manufactured with, unless there has been an update to the wiring harness by the manufacturer. - Nick at Pelican Parts  
Rash Comments: Audi a4 2002 1.6 petrol not starting after runnin fine day before found a bad spark plug lead wud this cause it wants to start but won't and how do I replace plugs seems hard things in way
January 19, 2015
  Followup from the Pelican Staff: If the engine flooded from the bad wire, it may not start.

I can't help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and fuel pressure, volume, quality and engine compression. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
 
bm647 Comments: Sir.Nick thank you so much..but another quick question when I tried removing the coils like in this pg my clips just snap and broke easily with a single push no force need just easily its my ignition coil harnest would that little clip cause any damage?? Until I get my part from the store
January 8, 2015
  Followup from the Pelican Staff: If the connector clip is broken, the connector will not stay seated. This can cause coil issues. - Nick at Pelican Parts  
bm647 Comments: I have a 2000 Audi A4 1.8t manual transmission I washed the engine cuz it was filthy dirty after I washed the engine I drove home fine later on I started the car again and the engine shakes rough idle and the check engine light came on please help I got the misfire code P0300 p0301 p0302 is
January 4, 2015
  Followup from the Pelican Staff: Remove the ignition coils and see if there is water in the spark plug tubes. Other than that, let the engine dry out. It should be oK. - Nick at Pelican Parts  
Robert Comments: I drive an audi 2002 1.8t why would there be oil in the spark plugs? Also when I put it in drive the signal for D-Drive on the display doesn't show it just blinks all the letters?
January 1, 2015
  Followup from the Pelican Staff: On top of the plugs? Leaking valve cover seals. - Nick at Pelican Parts  
Badassstang Comments: I have a 2001 vw golf 1.8 turbo my water in resorvoir is boiling but my temp gauge stays at 190. Checked flow of water pump seems to have flow. 155 compression at all four cylinders
August 26, 2014
  Followup from the Pelican Staff: I would pressure test the cooling system. If the system will not hold pressure and there are no external leaks the head gasket may be faulty. - Nick at Pelican Parts  
FABB Comments: so i parked my 2003 a4 quattro 1.8t…literally 5 minutes later i pulled each coil and replaced my plugs..put packs back on. got in car tryed starting and no fire. the service light came on….so i cleared the service light…put old plugs back in nothing…..i smell fuel so its getting gas…pulled all packs and put plugs in the end to see if spark…nothing….what would cause that??? i even replaced the battery cause i thought the one i had may have been to weak…still no start
June 4, 2014
  Followup from the Pelican Staff: How did you test for spark? Smelling fuel doesn't mean there is adequate pressure or volume. If the engine ran fine before the service, I would assume something is not connected properly or a part was damaged during the procedure. I would inspect each coil for damage, if two do not fire, the engine will not start. - Nick at Pelican Parts  
chris Comments: I drive an audi a4.2.0 2004 model when the engine is not fully warm and I drive it as soon as I depress the clutch to gear down the engine just cutts of is it suppose to do like that? If not what's the cause?
December 22, 2012
  Followup from the Pelican Staff: First thing to do is check the ECM for fault codes. Once that is done, check fuel pressure, volume and quality. Start with the basics to see what is missing when the engine stalls.- Nick at Pelican Parts  

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Project/Wish List]
  [Privacy Statement]  [Contact Us] [About Us] [Shipping] [Careers]

Copyright © Pelican Parts Inc. -    DMCA Registered Agent Contact Page

Page last updated: Fri 12/9/2016 02:01:55 AM