Audi 100/A6 (C4 92-97) FAQ Digest
04-25-2007, 07:26 AM
#141
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One refinement
you said "When replacing pads or rotors the fluid in the brake fluid reservoir will raise since the pistons are pushed back into the calipers and the fluid will travel back towards the reservoir. Use a syringe to remove some excess brake fluid and place an old towel around the reservoir to avoid spill and paint damage. Brake fluid is highly toxic and will harm you, therefore handle it with care."
My preference is to not force brake fluid back up the lines and into the master cylinder. There have been reports of debris from the line sticking in check valves or other system components and causing problems. I attribute a problem with a sticky caliper I had after a pad change to this.
I prefer to open the bleeder screw when compressing the pistons and allowing the old brake fluid to run out of the caliper.
My preference is to not force brake fluid back up the lines and into the master cylinder. There have been reports of debris from the line sticking in check valves or other system components and causing problems. I attribute a problem with a sticky caliper I had after a pad change to this.
I prefer to open the bleeder screw when compressing the pistons and allowing the old brake fluid to run out of the caliper.
05-02-2007, 03:52 PM
#143
Buyer's Guide
So you want to buy a C4 body 100 or A6? Here's the check off list of the most common things that go wrong, or need attention:
First of all bring the brightest flashlight you own and do an extremely thorough inspection in, under and around the engine, and on the back side of the engine inspect the steering rack that's along the firewall.
The big deal with these engines is oil leaks:
-Valve covers
-Right rear cam plug
-Valley pan gasket below the intake manifold (pop off the top plastic engine cover to view down into here)
-Power steering pump there at the top front of the engine
-Front crank seal
-Right transmission output flange seal
-Rear transmission output flange seal
-Rear differential seals (x3)
-Steering rack front torn boot
Next on your list is suspension clunks/thuds:
-Sway bar mounts loose
-Sway bar bushings bad
-Lower control arm bushings bad
-Engine mounts bad
-Transmission mounts bad
-Front strut top bushings bad
-Rear upper control arms bad
-Front and or rear struts bad
-CV boots and/or joints bad...front and rear
Then there's the interior items:
-Bad ignition switch (things don't work unless the switch is manually returned to the "run" position and jiggled)
-Instrument lights that don't work
-Power mirror "direction adjustment button" lights don't work
-Climate control lights don't work
-Ashtray light doesn't work
-Outside air temp reading doesn't work and/or doesn't light up (lower middle of instrument panel)
-Shift pattern indicator in instrument cluster doesn't work and/or doesn't light up
-Shift pattern indicator in the center console doesn't light up
-Instrument cluster warning chime doesn't work
-Instrument cluster "auto check" system doesn't work
-Stereo doesn't work and/or powered speakers are noisey
-Stereo has poor reception
-Right door mirror doesn't auto-dip when reverse is engaged and the right mirror adjust button is depressed (reverse lights probably don't work either)
-Sunroof doesn't function properly in all modes/positions....or does, but is noisey
-Power window switches don't work or windows don't work or are noisey
-Seat memory buttons down low on driver's door don't work
-Alarm doesn't work
-Key fob(s) or infrared key(s) don't work for locking and unlocking the car
-Power locks don't work
-Reverse lights don't come on in Reverse
-Climate control doesn't function properly or functions, but you can't get different flap or vent modes to work
-Recirculation flap behind glove box doesn't function (open glove box, turn on A/C, push recirc button and flap should come open)
-Smell of coolant and/or windows stay fogged up when heater is on due to leaking heater core(this is a $1,200 repair at the dealer!)
-Rattles from the rear hatch interior panels
-Rear wiper doesn't work
-Rear upper brake light doesn't work
-Rear fog light doesn't work (there's only one)
-Interior lights above doors that don't work and/or have broken slider switches
-Footwell lights for the driver and front passenger that don't light
-Seat heater lights that don't work
-Seat heaters that don't work
And the Mechanical stuff:
-Coolant temp gauge (on the far left) should stay parked on that wide white line at about 11 o'clock. It should take it about 5-10min to get to that temp. If it stays low, you have a bad thermostat that is stuck open or simply opening too soon. This will cause poor gas mileage and more than likely the car won't pass smog inspection because the fuel injection never goes into "closed loop" to allow the Oxygen sensors to function.
-Knocking/rattling/ticking on cold start or under load
-Weird shifting from the automatic
-Noise from the power steering especially at full lock
-Power steering that goes away at idle, like when parking
-Rough idle
-Uneven idle
-Rattling from the catalytic convertors
So there's your laundry list!
I bought my '95 with 175k on it, and I have repaired 60% of the things on the list above in the first 10 months.......I'm not kidding.
That being said, we love the car. Never thought I'd be in a "station wagon" nor did my wife, but it was love at first sight when we went to see it, and after the test drive we were hooked.
These all burn oil by design because they have low tension piston rings, so keep an eye on it!
They only get about 19mpg around town and maybe 24-25 on the highway, that's it. Less if you're out enjoying them, so be prepared for 19 gallons of fuel every 6 days or sooner!
The trade is worth it though. Look in my picture poster of a sedan that hit a car while towing a trailer and then rolled, landing on the roof, and you'll see how strong they are!
First of all bring the brightest flashlight you own and do an extremely thorough inspection in, under and around the engine, and on the back side of the engine inspect the steering rack that's along the firewall.
The big deal with these engines is oil leaks:
-Valve covers
-Right rear cam plug
-Valley pan gasket below the intake manifold (pop off the top plastic engine cover to view down into here)
-Power steering pump there at the top front of the engine
-Front crank seal
-Right transmission output flange seal
-Rear transmission output flange seal
-Rear differential seals (x3)
-Steering rack front torn boot
Next on your list is suspension clunks/thuds:
-Sway bar mounts loose
-Sway bar bushings bad
-Lower control arm bushings bad
-Engine mounts bad
-Transmission mounts bad
-Front strut top bushings bad
-Rear upper control arms bad
-Front and or rear struts bad
-CV boots and/or joints bad...front and rear
Then there's the interior items:
-Bad ignition switch (things don't work unless the switch is manually returned to the "run" position and jiggled)
-Instrument lights that don't work
-Power mirror "direction adjustment button" lights don't work
-Climate control lights don't work
-Ashtray light doesn't work
-Outside air temp reading doesn't work and/or doesn't light up (lower middle of instrument panel)
-Shift pattern indicator in instrument cluster doesn't work and/or doesn't light up
-Shift pattern indicator in the center console doesn't light up
-Instrument cluster warning chime doesn't work
-Instrument cluster "auto check" system doesn't work
-Stereo doesn't work and/or powered speakers are noisey
-Stereo has poor reception
-Right door mirror doesn't auto-dip when reverse is engaged and the right mirror adjust button is depressed (reverse lights probably don't work either)
-Sunroof doesn't function properly in all modes/positions....or does, but is noisey
-Power window switches don't work or windows don't work or are noisey
-Seat memory buttons down low on driver's door don't work
-Alarm doesn't work
-Key fob(s) or infrared key(s) don't work for locking and unlocking the car
-Power locks don't work
-Reverse lights don't come on in Reverse
-Climate control doesn't function properly or functions, but you can't get different flap or vent modes to work
-Recirculation flap behind glove box doesn't function (open glove box, turn on A/C, push recirc button and flap should come open)
-Smell of coolant and/or windows stay fogged up when heater is on due to leaking heater core(this is a $1,200 repair at the dealer!)
-Rattles from the rear hatch interior panels
-Rear wiper doesn't work
-Rear upper brake light doesn't work
-Rear fog light doesn't work (there's only one)
-Interior lights above doors that don't work and/or have broken slider switches
-Footwell lights for the driver and front passenger that don't light
-Seat heater lights that don't work
-Seat heaters that don't work
And the Mechanical stuff:
-Coolant temp gauge (on the far left) should stay parked on that wide white line at about 11 o'clock. It should take it about 5-10min to get to that temp. If it stays low, you have a bad thermostat that is stuck open or simply opening too soon. This will cause poor gas mileage and more than likely the car won't pass smog inspection because the fuel injection never goes into "closed loop" to allow the Oxygen sensors to function.
-Knocking/rattling/ticking on cold start or under load
-Weird shifting from the automatic
-Noise from the power steering especially at full lock
-Power steering that goes away at idle, like when parking
-Rough idle
-Uneven idle
-Rattling from the catalytic convertors
So there's your laundry list!
I bought my '95 with 175k on it, and I have repaired 60% of the things on the list above in the first 10 months.......I'm not kidding.
That being said, we love the car. Never thought I'd be in a "station wagon" nor did my wife, but it was love at first sight when we went to see it, and after the test drive we were hooked.
These all burn oil by design because they have low tension piston rings, so keep an eye on it!
They only get about 19mpg around town and maybe 24-25 on the highway, that's it. Less if you're out enjoying them, so be prepared for 19 gallons of fuel every 6 days or sooner!
The trade is worth it though. Look in my picture poster of a sedan that hit a car while towing a trailer and then rolled, landing on the roof, and you'll see how strong they are!
05-08-2007, 06:32 AM
#144
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Another write-up with pictures.
No need to take off the radiator fans on the C4.
<a href="https://forums.audiworld.com/9080/msgs/406705.phtml">https://forums.audiworld.com/9080/msgs/406705.phtml</a>
<a href="https://forums.audiworld.com/9080/msgs/406705.phtml">https://forums.audiworld.com/9080/msgs/406705.phtml</a>
05-15-2007, 08:10 AM
#147
Induction Service aka cleaning your fuel injection system
Doing an induction service will really make your car run smoother, start easier, an may cure certain Check Engine Light (CEL's) codes, especially for the common "EGR Insufficient Flow" that we all suffer from.
Shops will charge you $135-$150 for this service, but here's how to do it yourself:
First you need to by the BG Products 3 or 4 can Fuel Injection Service Kit. These are sold on Ebay for $13-$24 per kit. That is an incredible deal, because a shop will sell just the can of fuel tank cleaner for about $30-$35.
The kit comes with an aerosol can w/ straw and that is for spraying out your throttle body.
There is a red and gold can to be used as concentrated induction cleaner.
A black and gold can is for pouring into your fuel tank just prior to filling up.
To do this service you first need to remove the black plastic intake plenum at the back of the engine. Once this is off, blast out the throttle body, first with the throttle plates closed, and then with them wide open. If you can fit your hand back there with a little bottle brush of some sort, that would really help the process. Just don't use a brush that's going to break down and leave it's little "hairs" behind!
With the plenum off, you also want to clean out the 2 plastic breather pipes that go from the rear of each valve cover to the plenum. These get very clogged, as do the fittings on the valve cover.
Once you have the throttle body clean, put the plenum back on with the breather pipes, and fire up the engine. It will be hard to start due to all the cleaner you've just sprayed in. Hold your foot to the floor in order to open the throttle plates fully and give the engine all the air it can handle. After a few seconds of cranking it'll fire right up. Hold it at about 1,500-2,000rpm and let it clear itself out.
Shut it back down and prepare to finish the induction service.
Remove the large diameter hose from the Evap Canister Purge Solenoid Valve that sits up on top, in between the fuel filter and the MAF. You want to remove the hose that comes out of the valve fitting which faces forward. This hose is going to take the contents of the red and gold can, a little at a time. See photo below submitted by Ryan Windsor in Canada. (Thanks man!)
<img src="http://ryanwindsor.homestead.com/files/car/Induction1.jpg">
Pop the top on the can, and you can pour the contents into a larger container, that way you can put the hose into the container. Just use something that won't tip over.
You need to start the engine and have the throttle held at about 2,000rpm. You can have a friend do this (for about 10-15min) or prop the throttle open by putting a screwdriver into the throttle linkage from just over the Idle Stabilizer and downward at an angle (you'll see it with a flashlight. You can also use the cruise control acuator to hold the throttle open as seen in this photo submitted by Ryan Windsor (thanks again!). Note that the round black device just to the left is the intake manifold switch over solenoid. You move the linkage on the passenger side of it toward the driver's side to open the internal butterfly plates.
<img src="http://ryanwindsor.homestead.com/files/car/Induction2.jpg">
Hold the throttle open, prop open the manifold change over valve so the intake runners are fully opened, and let the hose start sucking down the magic sauce.
You'll see some smoke from the tailpipe and that's normal.
Once the can is empty, shut down the engine and let sit for 15min. Put it all back together during this time and then go for a nice drive at speed out on the highway/freeway.
The final step is to go top off your fuel tank and prior to filling up, pour in the contents of the black and gold can. Hint: bring a funnel that will fit into the opening in the fuel filler neck otherwise you can't pour in the can.
Shops will charge you $135-$150 for this service, but here's how to do it yourself:
First you need to by the BG Products 3 or 4 can Fuel Injection Service Kit. These are sold on Ebay for $13-$24 per kit. That is an incredible deal, because a shop will sell just the can of fuel tank cleaner for about $30-$35.
The kit comes with an aerosol can w/ straw and that is for spraying out your throttle body.
There is a red and gold can to be used as concentrated induction cleaner.
A black and gold can is for pouring into your fuel tank just prior to filling up.
To do this service you first need to remove the black plastic intake plenum at the back of the engine. Once this is off, blast out the throttle body, first with the throttle plates closed, and then with them wide open. If you can fit your hand back there with a little bottle brush of some sort, that would really help the process. Just don't use a brush that's going to break down and leave it's little "hairs" behind!
With the plenum off, you also want to clean out the 2 plastic breather pipes that go from the rear of each valve cover to the plenum. These get very clogged, as do the fittings on the valve cover.
Once you have the throttle body clean, put the plenum back on with the breather pipes, and fire up the engine. It will be hard to start due to all the cleaner you've just sprayed in. Hold your foot to the floor in order to open the throttle plates fully and give the engine all the air it can handle. After a few seconds of cranking it'll fire right up. Hold it at about 1,500-2,000rpm and let it clear itself out.
Shut it back down and prepare to finish the induction service.
Remove the large diameter hose from the Evap Canister Purge Solenoid Valve that sits up on top, in between the fuel filter and the MAF. You want to remove the hose that comes out of the valve fitting which faces forward. This hose is going to take the contents of the red and gold can, a little at a time. See photo below submitted by Ryan Windsor in Canada. (Thanks man!)
<img src="http://ryanwindsor.homestead.com/files/car/Induction1.jpg">
Pop the top on the can, and you can pour the contents into a larger container, that way you can put the hose into the container. Just use something that won't tip over.
You need to start the engine and have the throttle held at about 2,000rpm. You can have a friend do this (for about 10-15min) or prop the throttle open by putting a screwdriver into the throttle linkage from just over the Idle Stabilizer and downward at an angle (you'll see it with a flashlight. You can also use the cruise control acuator to hold the throttle open as seen in this photo submitted by Ryan Windsor (thanks again!). Note that the round black device just to the left is the intake manifold switch over solenoid. You move the linkage on the passenger side of it toward the driver's side to open the internal butterfly plates.
<img src="http://ryanwindsor.homestead.com/files/car/Induction2.jpg">
Hold the throttle open, prop open the manifold change over valve so the intake runners are fully opened, and let the hose start sucking down the magic sauce.
You'll see some smoke from the tailpipe and that's normal.
Once the can is empty, shut down the engine and let sit for 15min. Put it all back together during this time and then go for a nice drive at speed out on the highway/freeway.
The final step is to go top off your fuel tank and prior to filling up, pour in the contents of the black and gold can. Hint: bring a funnel that will fit into the opening in the fuel filler neck otherwise you can't pour in the can.
05-19-2007, 08:09 AM
#148
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Torque Specifications
Component
Tightening Torques
ATF oil pan to transmission
M6 6 Nm (53 in. lb)
ATF drain plug to ATF oil pan
M14 35 Nm (26 ft lb)
ATF filler tube to ATF oil pan
M24 40 Nm (30 ft lb)
ATF filler tube to transmission
M8 23 Nm (17 ft lb)
ATF filler tube to engine
6-cylinder engine)
M6 9 Nm (80 in. lb)
* Short Note... Use an apropriate Torque wrench...
I used a big one with low torque values and ended up braking a bolt so be careful and don't rely only in the wrench... Keep using your intuition!
Tightening Torques
ATF oil pan to transmission
M6 6 Nm (53 in. lb)
ATF drain plug to ATF oil pan
M14 35 Nm (26 ft lb)
ATF filler tube to ATF oil pan
M24 40 Nm (30 ft lb)
ATF filler tube to transmission
M8 23 Nm (17 ft lb)
ATF filler tube to engine
6-cylinder engine)
M6 9 Nm (80 in. lb)
* Short Note... Use an apropriate Torque wrench...
I used a big one with low torque values and ended up braking a bolt so be careful and don't rely only in the wrench... Keep using your intuition!