Tuesday, August 11, 2009
Coil Pack Repair/Reinforcement for VR6's:
Part I - Background
1) What is a coil pack? Thanks for asking. The coil pack replaces
distributor caps on "new and improved" ignition system. Instead of having a
rotor and distributor cap "distribute" the ignition spark to individual
cylinders at the right time and order, the spark is controlled
electronically though the electronic ignition system. The coil pack is
where the actual electrical current (spark) is sent to each spark plug via
the wires.
2) The pack is generally comprised of a metal base with a plastic
top (insulates the metallic parts so the current is not immediately
grounded).
3) The coil pack is located on the right side of the engine (look
from the front) under the plastic manifold covers. Just follow the pretty
spark plug wires to the end and they attach to the coil pack.
4) It seems that the VR6 coil packs (at least pre 98's) just suck.
I am not sure if the plastic is not formulated properly, if the molding is
not performed properly or if the design does not distribute stress/heat well
but by listening to the problems people on this list have had, the coil pack
is NOT a quality part. Either that or it is designed obsolescence, keeping
the dealer stocked with easy, $500 repairs every 30,000 miles.
Part II - Diagnosis
1) If you have noticed that on cool, damp days or after driving in
the rain (especially on the highway, especially behind cars/trucks) the
engine is running rough and misfiring, chances are the coil pack has a
crack(s).
2) When this happens, the "check engine light" WILL come on
immediately, because the emissions just went to hell.
3) If possible, pull over and pop the hood ASAP. If it is a
cracked coil pack you will notice (at least I did each time there was a
problem):
a) a fairly loud "snapping" or "clicking" sound immediately
followed by a rough spot in the idle.
b) visible sparks running along the coil pack, generally
from the wire terminal (where the spark plug wires attach) towards the metal
part of the coil pack. Each spark is tracing a water filled crack and
grounding the spark to the engine block rather than travelling along the
spark plug wire. Try to remember or draw the location of the sparks.
4) If you cannot pull over, or if you want to check later after the
weather gets a bit nicer you can easily simulate rain. Get a plant spray
bottle/mister and fill with clean water. Start up the engine and give the
coil pack area a good misting with the bottle. It may take a few sprays to
get the pack nice and wet. This should start the light show again. Try to
remember where the crack(s) is or make a sketch.
[ It would also help if you do this in a darkened garage or at dusk. It would make spotting the sparks a lot easier. Obviously. aqn ]
5) You now know you have the dreaded cracked coil pack. But have
no fear, there are options...
Part III - Repair Options
1) Take car to dealer, tell them the coil pack is bad. They will
respond "that's nice but we will have to confirm" ($56.49). They will then
call back several hours later saying "you have a bad coil pack" (duh) and
that for just $350 in parts and $100 in labor we can put on a new one. So
pony up $500.
2) Lucky for you, there are engineers out here who just can't stand
it when a biased party tells me that an inferior part needs to be replaced
with the same inferior part. So like all good men, especially engineers, I
start to tinker. Leading to a "fix" that has worked for 11,000 miles so far
- The $3.49 Epoxy Solution.
Part IV - The $3.49 Epoxy Solution
1) Drive a different car to Home Depot, Lowe's, etc. and get a
package of high strength, high temperature epoxy. I *think* the brand I
used was "Poxy-Weld"? It is the classic twin tube syringe, silver in color
with a cardboard packaging display that unfolded to give product
information. It is made to repair metal, plastic, etc. with higher
operating temperatures. It has Kevlar flakes to add
strength. I think the one I used was rated to 250 or 350 degrees. It was
like $3.49 for the tube.
2) In order to make the repair you will need:
torx wrenches or driver
allen (hex) wrenches or driver
damp rag
hair dryer
epoxy
12 hours (1 hour working, 11 hours waiting)
3) Coil pack removal. This is very easy. First remove the plastic
manifold covers. This requires torx head wrenches/driver. IMPORTANT.
Before trying to loosen the screws, bang the top of the wrench/driver with a
hammer while the wrench/driver is on the screw. Aluminum tends to "corrode"
quickly (look at the manifold) and slightly bond to itself. By hitting with
a hammer, the bond is broken and the screws can be easily removed. I know
this from experience (ie partially stripped screw heads). If you strip the
screw heads, I used a slightly larger allen wrench and literally hammered it
into the torx grooves. Of course you then need new screws ($12). Once the
four screws are out, plastic covers come off easily. You can now see the
whole coil pack.
4) Unplug the wire harness attached to the top of the coil pack and
move out of the way. If I remember right it has pinch clips on the side to
unlock the harness. Unplug the spark plug wires. Make a diagram of which
plug number goes where.
5) The coil pack is held to the engine block by four, long allen
(hex) screws. I found a hex driver with an articulated joint made the
removal easier. A socket wrench should also work. Unscrew and remove the
pack. It is a bit heavier than you might think so be careful when removing
the last two screws.
6) Take coil pack inside. Ignore the "you are not a mechanic"
insults coming from the living room (be the ball Danny). Take off plastic
cover on the top of the pack (just pop over the small clips). Wash off the
coil pack with a damp cloth. If it is really dirty, a bit of Dawn can work
wonders. Just make sure to wipe off the soap well. You will now want to
dry the pack WELL with the hair dryer. I was probably a bit anal about it
but I sat in front of the TV for like 20 minutes just drying the pack.
Since there is no real way to tell if all the water is out of the cracks, I
was conservative.
7) You are now ready for the epoxy. Mix a healthy amount is a
small disposable container. I used a popsicle stick to mix and spread.
Start applying a liberal coat of epoxy. The first time I did it, I only
covered the places I had seen sparks. Of course about two weeks after the
first fix, a new crack or one I had not seen developed so I did it again.
This time I covered the entire plastic portion of the coil pack.
Concentrate on the area between each terminal and the edge of the pack. No
problem since. So either coat the cracked areas or just do the whole thing.
I would recommend the whole thing. The epoxy tends to get a bit sticky so
it may work best doing two batchings.
8) Set coil pack in a warm place to dry overnight. I did this in
December so by a radiator worked well. Just don't put outside since it
makes the curing take a lot longer.
9) Reinstall the next morning. I actually did this before work one
day and it took all of about 10 minutes. Put plastic cover back on pack.
Install pack with four hex bolts and reattach the wire harness. Plug in
spark plug wires in SAME LOCATIONS. Install plastic manifold covers (I put
some grease on the aluminum screws before installing to prevent locking).
10) Start car and she should be running like new. It will take at
least 3 warm-up/cool-down cycles to reset the "check engine light"
1) What is a coil pack? Thanks for asking. The coil pack replaces
distributor caps on "new and improved" ignition system. Instead of having a
rotor and distributor cap "distribute" the ignition spark to individual
cylinders at the right time and order, the spark is controlled
electronically though the electronic ignition system. The coil pack is
where the actual electrical current (spark) is sent to each spark plug via
the wires.
2) The pack is generally comprised of a metal base with a plastic
top (insulates the metallic parts so the current is not immediately
grounded).
3) The coil pack is located on the right side of the engine (look
from the front) under the plastic manifold covers. Just follow the pretty
spark plug wires to the end and they attach to the coil pack.
4) It seems that the VR6 coil packs (at least pre 98's) just suck.
I am not sure if the plastic is not formulated properly, if the molding is
not performed properly or if the design does not distribute stress/heat well
but by listening to the problems people on this list have had, the coil pack
is NOT a quality part. Either that or it is designed obsolescence, keeping
the dealer stocked with easy, $500 repairs every 30,000 miles.
Part II - Diagnosis
1) If you have noticed that on cool, damp days or after driving in
the rain (especially on the highway, especially behind cars/trucks) the
engine is running rough and misfiring, chances are the coil pack has a
crack(s).
2) When this happens, the "check engine light" WILL come on
immediately, because the emissions just went to hell.
3) If possible, pull over and pop the hood ASAP. If it is a
cracked coil pack you will notice (at least I did each time there was a
problem):
a) a fairly loud "snapping" or "clicking" sound immediately
followed by a rough spot in the idle.
b) visible sparks running along the coil pack, generally
from the wire terminal (where the spark plug wires attach) towards the metal
part of the coil pack. Each spark is tracing a water filled crack and
grounding the spark to the engine block rather than travelling along the
spark plug wire. Try to remember or draw the location of the sparks.
4) If you cannot pull over, or if you want to check later after the
weather gets a bit nicer you can easily simulate rain. Get a plant spray
bottle/mister and fill with clean water. Start up the engine and give the
coil pack area a good misting with the bottle. It may take a few sprays to
get the pack nice and wet. This should start the light show again. Try to
remember where the crack(s) is or make a sketch.
[ It would also help if you do this in a darkened garage or at dusk. It would make spotting the sparks a lot easier. Obviously. aqn ]
5) You now know you have the dreaded cracked coil pack. But have
no fear, there are options...
Part III - Repair Options
1) Take car to dealer, tell them the coil pack is bad. They will
respond "that's nice but we will have to confirm" ($56.49). They will then
call back several hours later saying "you have a bad coil pack" (duh) and
that for just $350 in parts and $100 in labor we can put on a new one. So
pony up $500.
2) Lucky for you, there are engineers out here who just can't stand
it when a biased party tells me that an inferior part needs to be replaced
with the same inferior part. So like all good men, especially engineers, I
start to tinker. Leading to a "fix" that has worked for 11,000 miles so far
- The $3.49 Epoxy Solution.
Part IV - The $3.49 Epoxy Solution
1) Drive a different car to Home Depot, Lowe's, etc. and get a
package of high strength, high temperature epoxy. I *think* the brand I
used was "Poxy-Weld"? It is the classic twin tube syringe, silver in color
with a cardboard packaging display that unfolded to give product
information. It is made to repair metal, plastic, etc. with higher
operating temperatures. It has Kevlar flakes to add
strength. I think the one I used was rated to 250 or 350 degrees. It was
like $3.49 for the tube.
2) In order to make the repair you will need:
torx wrenches or driver
allen (hex) wrenches or driver
damp rag
hair dryer
epoxy
12 hours (1 hour working, 11 hours waiting)
3) Coil pack removal. This is very easy. First remove the plastic
manifold covers. This requires torx head wrenches/driver. IMPORTANT.
Before trying to loosen the screws, bang the top of the wrench/driver with a
hammer while the wrench/driver is on the screw. Aluminum tends to "corrode"
quickly (look at the manifold) and slightly bond to itself. By hitting with
a hammer, the bond is broken and the screws can be easily removed. I know
this from experience (ie partially stripped screw heads). If you strip the
screw heads, I used a slightly larger allen wrench and literally hammered it
into the torx grooves. Of course you then need new screws ($12). Once the
four screws are out, plastic covers come off easily. You can now see the
whole coil pack.
4) Unplug the wire harness attached to the top of the coil pack and
move out of the way. If I remember right it has pinch clips on the side to
unlock the harness. Unplug the spark plug wires. Make a diagram of which
plug number goes where.
5) The coil pack is held to the engine block by four, long allen
(hex) screws. I found a hex driver with an articulated joint made the
removal easier. A socket wrench should also work. Unscrew and remove the
pack. It is a bit heavier than you might think so be careful when removing
the last two screws.
6) Take coil pack inside. Ignore the "you are not a mechanic"
insults coming from the living room (be the ball Danny). Take off plastic
cover on the top of the pack (just pop over the small clips). Wash off the
coil pack with a damp cloth. If it is really dirty, a bit of Dawn can work
wonders. Just make sure to wipe off the soap well. You will now want to
dry the pack WELL with the hair dryer. I was probably a bit anal about it
but I sat in front of the TV for like 20 minutes just drying the pack.
Since there is no real way to tell if all the water is out of the cracks, I
was conservative.
7) You are now ready for the epoxy. Mix a healthy amount is a
small disposable container. I used a popsicle stick to mix and spread.
Start applying a liberal coat of epoxy. The first time I did it, I only
covered the places I had seen sparks. Of course about two weeks after the
first fix, a new crack or one I had not seen developed so I did it again.
This time I covered the entire plastic portion of the coil pack.
Concentrate on the area between each terminal and the edge of the pack. No
problem since. So either coat the cracked areas or just do the whole thing.
I would recommend the whole thing. The epoxy tends to get a bit sticky so
it may work best doing two batchings.
8) Set coil pack in a warm place to dry overnight. I did this in
December so by a radiator worked well. Just don't put outside since it
makes the curing take a lot longer.
9) Reinstall the next morning. I actually did this before work one
day and it took all of about 10 minutes. Put plastic cover back on pack.
Install pack with four hex bolts and reattach the wire harness. Plug in
spark plug wires in SAME LOCATIONS. Install plastic manifold covers (I put
some grease on the aluminum screws before installing to prevent locking).
10) Start car and she should be running like new. It will take at
least 3 warm-up/cool-down cycles to reset the "check engine light"
Slow Coolant Front Of Motor on vw vr6
OK, it's monsoon season in Glasgow today (with big sparks in the sky and rumbling too) so I'll take the time to post up some pictures I've taken during this crack pipe replacement job, and comment along the way. I hope people will find this helpful when they have to do it.
First up, here's the bumper bracket with the remains of one of the 4 big bolts (the one on the right of the picture) you need to undo to get the bumper out. These bolts require a breaker bar to shift them and unfortunately one of mine has decided to become a part of the frame, probably at the molecular level. I'm still not sure what I'm going to do to get this out, but I've got a tap and die set, so hopefully that can get the remaining bits out once I file them down enough:
OK, the next two pictures show the common damage with a crack pipe. Firstly, the ends crumble away. Secondly the branch pipe that goes to the oil cooler snaps off. On mine this only snapped off while I was trying to remove the crack pipe, but other people have it coming off on its own. Mine may have been leaking there, but the real leak in mine was one of the oil cooler pipes, which I totally advise replacing at the same time. There's two of them and they're £6.50ish each. You may want to get new clips too as I snapped one of them trying to remove it. You'll note the seals are missing. The first picture is the engine end and the seal was stuck in the block part. The other end I think I removed myself. My crack pipe was original (manufactured in 1993, but my thermostat housing bits and radiator seem to date from 2001, so I reckon I've had work on my cooling system the year before I got the car.
The next two pictures show where the bolts for the bumper go. The first is from underneath, at the passenger side. The second is the channel where the bumper bracket in the first picture slides in. Note that on mine, the two bolts nearest the bumper were in good condition and came out OK. The two nearest the back of the car were much more badly corroded and one of these snapped. Take care with the back bolts.
Next, this is what your car looks like when you've got the bumper, slam panel and radiator out. Not pretty! Note the very rusty block behind the dipstick holder. This is where the leak was and may well have been contributing to the rust. Also note the oily part on the right. This oil appears to be coming from the rocker cover gasket, so I'll need to do that at some point. You can also see some general corrosion on the subframe bit, which I've now painted with some hammerite.
OK, the next two pictures show the engine with crack pipe and thermostat housing removed. The corrosion in the block where the crack pipe goes is really quite horrendous and it requires lots of cleaning up with emery paper or Dremels (taking great care not to remove too much material). I'm not sure how successful I've been because I got interrupted with the monsoon, but you need to check here carefully for leaks after doing the job. The mating surface where the thermostat housing goes was very good on mine. I cleaned up with brake cleaner and emery paper.
The next two pictures show the new thermostat housing assembled and also a mock up of how it goes with the crack pipe. Note the thermostat inside the lower part. Note how I've positioned it such that the metal pieces going to the apex of the thermostat are not restricting the flow of coolant through the crack pipe piece (you'll know what I mean when you see the thermostat). My old thermostat was positioned such that the flow was restricted by this piece which is probably not a good idea. Note the sensors assembled in their original order (or at least the original order in MY car!). In the second picture you'll see a jubilee clip on the oil cooler hose but I decided to just get a new clip to replace the one I snapped from the dealer since I was going there for bolts anyway.
Next is a still life of Corrado parts. Bottom left is the snapped bumper bolt next to an intact one. Bottom right is a snapped bolt inside the radiator spacing piece. This piece is almost £10 from the dealer!!! If you have the time, drill it out and tap a new thread in. Unbelievably the bolt was "on back order". There was not a single bolt for this in the whole of the UK. I declined to wait and bought an M6 bolt from Halfords to use with my replacement spacer piece. The original is 15mm long and the Halfords replacement is 20mm. If need be I can cut 5mm off it but I don't think it will be necessary. Top middle are two plastic clips that fit on the crack pipe and are used (I think!) to hold the alternator wire up, but it doesn't quite fit on mine as you'll see in later photos. Note the inclusion of daisies to finish off the piece. This photo should be in the Tate Modern really.
Next is a photo with everything re-assembled, but still missing the radiator. This is the point I was at when the monsoon started, so it's still in this state. To get the new crack pipe in was really tough. In the end I resorted to tapping it in with gentle force with a block of wood and a hammer. It actually goes in quite far and is actually very tight when it's in. I just wonder if I've tapped it in too far. I'll explain further with the next photo. Note that the pipe isn't horizontal (it's not meant to be). Note the careful positioning of the two oil cooler hoses. I think mine were under stress as they were very much more crushed up against the previous crack pipe. One had actually partially melted where it touched the crack pipe. Note the clips holding the alternator wire. I've had to remove the left one out of its alignment pin on the crack pipe (that's what those pins are for) to get it to sit nicely with the wire.
OK, here's a close-up of the right side of the crack pipe seated inside the thermostat housing piece. Have I tapped the crack pipe too far into the block? I'm slightly concerned that the alignment notch isn't hard up against the thermostat housing piece as it could be, but everything else is aligned correctly. I think it's still sealed inside OK and am hoping that this is deliberately designed to allow some variation. The thermostat piece is a smooth uniform channel inside, which is perhaps deliberately made like this to allow for slight variations. Only testing will tell.
Here's a close-up of the engine block end of the crack pipe. Is this too far in the block? Is that even possible?
Lastly, here's a close-up of the two £6.50ish rubber hoses that you'd be mad not to replace at the same time. I re-used 3 clips and bought a new one to replace one I snapped. Take care and time to position these hoses to minimise stress and to try to keep them away from the crack pipe. Note that the two oil cooler ends are of larger diameter than the crack pipe and block ends of the pipes. Take care to put the right pipe in the right place. They are shaped for their positions. Take care to position the spring clips for easy access later, a point neglected by many.
OK, that's all the photos for now. Hope this is useful for others. It's not a tough job (assuming you get the bumper bolts out OK), it's just a bit time-consuming.
First up, here's the bumper bracket with the remains of one of the 4 big bolts (the one on the right of the picture) you need to undo to get the bumper out. These bolts require a breaker bar to shift them and unfortunately one of mine has decided to become a part of the frame, probably at the molecular level. I'm still not sure what I'm going to do to get this out, but I've got a tap and die set, so hopefully that can get the remaining bits out once I file them down enough:
OK, the next two pictures show the common damage with a crack pipe. Firstly, the ends crumble away. Secondly the branch pipe that goes to the oil cooler snaps off. On mine this only snapped off while I was trying to remove the crack pipe, but other people have it coming off on its own. Mine may have been leaking there, but the real leak in mine was one of the oil cooler pipes, which I totally advise replacing at the same time. There's two of them and they're £6.50ish each. You may want to get new clips too as I snapped one of them trying to remove it. You'll note the seals are missing. The first picture is the engine end and the seal was stuck in the block part. The other end I think I removed myself. My crack pipe was original (manufactured in 1993, but my thermostat housing bits and radiator seem to date from 2001, so I reckon I've had work on my cooling system the year before I got the car.
The next two pictures show where the bolts for the bumper go. The first is from underneath, at the passenger side. The second is the channel where the bumper bracket in the first picture slides in. Note that on mine, the two bolts nearest the bumper were in good condition and came out OK. The two nearest the back of the car were much more badly corroded and one of these snapped. Take care with the back bolts.
Next, this is what your car looks like when you've got the bumper, slam panel and radiator out. Not pretty! Note the very rusty block behind the dipstick holder. This is where the leak was and may well have been contributing to the rust. Also note the oily part on the right. This oil appears to be coming from the rocker cover gasket, so I'll need to do that at some point. You can also see some general corrosion on the subframe bit, which I've now painted with some hammerite.
OK, the next two pictures show the engine with crack pipe and thermostat housing removed. The corrosion in the block where the crack pipe goes is really quite horrendous and it requires lots of cleaning up with emery paper or Dremels (taking great care not to remove too much material). I'm not sure how successful I've been because I got interrupted with the monsoon, but you need to check here carefully for leaks after doing the job. The mating surface where the thermostat housing goes was very good on mine. I cleaned up with brake cleaner and emery paper.
The next two pictures show the new thermostat housing assembled and also a mock up of how it goes with the crack pipe. Note the thermostat inside the lower part. Note how I've positioned it such that the metal pieces going to the apex of the thermostat are not restricting the flow of coolant through the crack pipe piece (you'll know what I mean when you see the thermostat). My old thermostat was positioned such that the flow was restricted by this piece which is probably not a good idea. Note the sensors assembled in their original order (or at least the original order in MY car!). In the second picture you'll see a jubilee clip on the oil cooler hose but I decided to just get a new clip to replace the one I snapped from the dealer since I was going there for bolts anyway.
Next is a still life of Corrado parts. Bottom left is the snapped bumper bolt next to an intact one. Bottom right is a snapped bolt inside the radiator spacing piece. This piece is almost £10 from the dealer!!! If you have the time, drill it out and tap a new thread in. Unbelievably the bolt was "on back order". There was not a single bolt for this in the whole of the UK. I declined to wait and bought an M6 bolt from Halfords to use with my replacement spacer piece. The original is 15mm long and the Halfords replacement is 20mm. If need be I can cut 5mm off it but I don't think it will be necessary. Top middle are two plastic clips that fit on the crack pipe and are used (I think!) to hold the alternator wire up, but it doesn't quite fit on mine as you'll see in later photos. Note the inclusion of daisies to finish off the piece. This photo should be in the Tate Modern really.
Next is a photo with everything re-assembled, but still missing the radiator. This is the point I was at when the monsoon started, so it's still in this state. To get the new crack pipe in was really tough. In the end I resorted to tapping it in with gentle force with a block of wood and a hammer. It actually goes in quite far and is actually very tight when it's in. I just wonder if I've tapped it in too far. I'll explain further with the next photo. Note that the pipe isn't horizontal (it's not meant to be). Note the careful positioning of the two oil cooler hoses. I think mine were under stress as they were very much more crushed up against the previous crack pipe. One had actually partially melted where it touched the crack pipe. Note the clips holding the alternator wire. I've had to remove the left one out of its alignment pin on the crack pipe (that's what those pins are for) to get it to sit nicely with the wire.
OK, here's a close-up of the right side of the crack pipe seated inside the thermostat housing piece. Have I tapped the crack pipe too far into the block? I'm slightly concerned that the alignment notch isn't hard up against the thermostat housing piece as it could be, but everything else is aligned correctly. I think it's still sealed inside OK and am hoping that this is deliberately designed to allow some variation. The thermostat piece is a smooth uniform channel inside, which is perhaps deliberately made like this to allow for slight variations. Only testing will tell.
Here's a close-up of the engine block end of the crack pipe. Is this too far in the block? Is that even possible?
Lastly, here's a close-up of the two £6.50ish rubber hoses that you'd be mad not to replace at the same time. I re-used 3 clips and bought a new one to replace one I snapped. Take care and time to position these hoses to minimise stress and to try to keep them away from the crack pipe. Note that the two oil cooler ends are of larger diameter than the crack pipe and block ends of the pipes. Take care to put the right pipe in the right place. They are shaped for their positions. Take care to position the spring clips for easy access later, a point neglected by many.
OK, that's all the photos for now. Hope this is useful for others. It's not a tough job (assuming you get the bumper bolts out OK), it's just a bit time-consuming.
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