Oil cooler repair on 40v 2000 +A8 - LONG post..even for me
03-27-2007, 07:37 PM
#1
AudiWorld Senior Member
Thread Starter
Oil cooler repair on 40v 2000 +A8 - LONG post..even for me
Did the job this weekend with a lot of stops and starts because she who must be obeyed...must be obeyed. Anyhow, the procedure for the repair of the oil cooler "O" rings and plastic pipe is almost identical to that posted on Audipages.com for the earlier 32V engine. The differences are slight, so here follows my rambling observations.
Drive the car up on rhino ramps, disconnect negative battery cable - 10mm box wrench.
From above, unscrew the four screws securing the top of the airbox and remove - straight or phillips screwdriver, your choice, lift cover off, leave the AFM inside and lie it back on the intake or up near the firewall, remove bottom half of airbox by unbolting the 2 10mm nuts at the top of the box closest to the firewall, tip it up back toward the engine ecu box and lay it there...it still has the secondary air pump inside it...secure it out of the way with a bungee if you like.
From below remove front undertray - 10mm socket and straight screwdriver, drain coolant (I didn't), remove the bottom of the oil filter housing with a really really big socket - drain it first if you don't want to get your dress dirty (I didn't..it was a nice dress too).
Still under the car, disconnect alternator wiring - straight screwdriver to pop the rubber cap off the "big" terminal nut - hmmmm 10 or 12 mm nut, unbolt the little terminal nut - 8 mm socket, then pop off the female blade connector - straight screwdriver again or small pliers. Pull off the 90degree duct elbow which feeds cooling air to the alternator, it just slips off.
On the ground in front of the car: Using a 19 mm socket wrench with a longer driver handle on the fixed lug (shaped like a 19mm nut)on the idler pulley bracket, start at the 6 o'clock position and try to push it counter clockwise and hold it there with one hand while sliding the serpentine belt off the alternator pulley. The tensioner pulley is on a spring loaded bracket which is not tightened down in a fixed position, rather, it is held at the proper tension at all times by the spring, so it is free to adjust over the life of the belt,from cold to hot, etc.. this makes it real easy to loosen the belt as described and remove the belt...mind your fingers by the alternator pulley if you slip with the socket and the belt pulls tight...ouch. There is nothing scary about it, the belt tension is not really all that tight, it just feels tough if you use a short wrench or start at the wrong angle..lying on the ground, use a long handle socket wrench at 6 or 5 o'clock a steady counterclockwise push...like butta.
Still on the ground in front, the alternator is secured from the front only by Two bolts, a big long through bolt on top - 8mm allen socket, and a 13 mm short bolt at the 3 o'clock position when viewed from the front. Mine was practically welded in there and took a bit of wrestling to break free - a two hand grab and rock it back and forth affair, maybe a flat pry bar, but be mindful of what you are prying on and against.
Remove the Oil Cooler Assembly. Start of the soul trying tricky bit...remove the electrical plug to the oil pressure sender - a light squeeze with a pliers ought to do it, unscrew the sender - 21 or 22mm open end wrench, remove the five 8mm allen head bolts securing the cooler to the block, remove from below, mount the unit in a vise clamping the alternator bracket ear lightly in the jaws so that the matrix is facing the ceiling,remove the five torx (T25 I think??) screws holding the cooler matrix in place, clean up mating surfaces, replace the gaskets and reverse the process. Ha! If only it were that easy.
Getting the five 8mm allen head bolts out was a bear - 2 from below 3 from above. Of the two bottom bolts, the shorter one is toward the back of the car and is slightly obstructed by the top of the oil filter housing. I found that a LONG allen key was the trick to getting this one out..others have had success with wobbly sockets and the like.
Before starting any of these bolts, I inserted the allen key and then gave the back of the key a medium firm tap with a hammer to fully seat the key (and maybe shock the thresds a little...doubt it)...It is a two hand job: press the key inward with one hand while turning with the other, keep the misalignment to a minimum or you will pop out and risk rounding out the bolt head. The bottom front bolt was pretty easy with an 8mm socket wrench and a variety of extensions and a wobbly head adapter. Again, keep misalignment to a minimum and maintain steady inward pressure to prevent the key from popping out and stripping the bolt head. The top front bolt is another simple one. The middle one is blind, but still a pretty straight shot over the top of the external metal coolant pipe which comes from the back of the engine.
Said metal coolant pipe is secured to the oil cooler body with a single 10 mm bolt. I could not see how to remove the back of this pipe from the back of the engine and by Always Overcharged's account, it is a real bitch to do so. I am lazy. So, instead, I pulled it out of the oil cooler and it had enough slack to move out of the way to get the cooler out from below.
This pipe is really seated into the oil cooler body. I pulled, pryed, wiggled and tugged on it without much success, then I used a steering wheel puller with just the center bolt, slid an ear under the pipe and slowly tensioned the bolt and then it started to budge, continued pulling, prying, etc and it finally popped free. It has a rubber "O" ring which you will also replace. I must also confess to pulling on this pipe with a vise grips, you cringe, but it worked. Had it actually gotten ugly, I would have cut the pipe in half and then twisted it out of ther cooler body and then spliced it back together with hose and hose clamps later. It didn't quite come to that.
The top rear 8 mm allen head bolt tries mens' souls. It is blind, it is tight, and you've got no damned room to manuever. You can see the bolt head... barely...while lying under the car but you can't get the wrench in from below. You can slide the extension bar in from above, but you can't see squat...blind retard wrenching at its finest..an assistant lying under the car giving directions while you try and find the bolt from above would make it easier...maybe. Right about then I was thinking I really should have called Heinz, but there was only one 6 pack of Heiniken and I was fierce thirsty. Scratch one able bodied assistant. Wait, that didn't sound right.
If I had it to do over again, and I pray I don't, I would suggest buying the following items..several identical long 8mm hex keys and several 8 mm sockets. Cut the short head off one key so you are left with a long straight key and then cut the next two keys shorter in...say.. one inch increments and hotglue each one into one of the 8mm sockets. A long naked allen key is much skinnier than an extension bar and can get into tighter spots, the socket makes it easier to turn, but since the space is soooo tight, once you start to loosen a bolt, you need to switch to the next shorter homemade allen socket so you have clearance at the back of the wrench. It really is that cramped. Once you get it out, take hope, getting it out is the hardest part...but only by a little.
Now you've got it out of the car, remove the cooler matrix. I like a torx bit on a long extension bar with a socket wrench. This way you can push down with one hand while applying firm steady pressure on the wrench with the other. All 5 torx bolts came out unscathed this way...thanks to Always Overcharged for the heads up about these bolts, he was not so lucky. So, the extra effort here - mount it in a vise at the big alternator bolt contact points, and steady downward pressure with one hand and loosening pressure with the other - made it easy.
The unit will go back into the car without jacking on the engine block with loosened motor mounts or any other shennanigans, but it will only go in one right way and there are many wrong ways to try. Hard to describe, but if you are under the car and get stuck, read this and you will see what I mean. If you get it into the space but the oil filter mount is tilted outward toward the frame rail, forget it, it is wrong, you will never get the filter housing to tilt down past the frame rail. Take it back out from below and try it with the top of the unit tilted away from the block and the bottom close to it. You may have to rotate it a little, but it will go in this way so un-freakin-believably easy that you will want to dance a jig. Both during removal and reinstallation, be mindful not to bash the fairly fragile matrix against the engine block. It would really suck if this thing sprung a leak.
When you bolt it back up, note that there are two locating dowels - top left and lower right - and the plastic pipe to line up. Tighten it down evenly. If you get it cocked too far out of alignment, the bolts will be a little harder to turn. If they do, loosen the last bolt you tightened by a turn or two and see if that helps. This is where you want to be patient, no rush, in your happy place. Another really bad time to strip or break something.
I didn't have my Bentley available for this procedure as I just switched computers so I don't know what if anything they add to the processs.
I still think doing the fuel pump is easier.
Regards,
Brian C.
Drive the car up on rhino ramps, disconnect negative battery cable - 10mm box wrench.
From above, unscrew the four screws securing the top of the airbox and remove - straight or phillips screwdriver, your choice, lift cover off, leave the AFM inside and lie it back on the intake or up near the firewall, remove bottom half of airbox by unbolting the 2 10mm nuts at the top of the box closest to the firewall, tip it up back toward the engine ecu box and lay it there...it still has the secondary air pump inside it...secure it out of the way with a bungee if you like.
From below remove front undertray - 10mm socket and straight screwdriver, drain coolant (I didn't), remove the bottom of the oil filter housing with a really really big socket - drain it first if you don't want to get your dress dirty (I didn't..it was a nice dress too).
Still under the car, disconnect alternator wiring - straight screwdriver to pop the rubber cap off the "big" terminal nut - hmmmm 10 or 12 mm nut, unbolt the little terminal nut - 8 mm socket, then pop off the female blade connector - straight screwdriver again or small pliers. Pull off the 90degree duct elbow which feeds cooling air to the alternator, it just slips off.
On the ground in front of the car: Using a 19 mm socket wrench with a longer driver handle on the fixed lug (shaped like a 19mm nut)on the idler pulley bracket, start at the 6 o'clock position and try to push it counter clockwise and hold it there with one hand while sliding the serpentine belt off the alternator pulley. The tensioner pulley is on a spring loaded bracket which is not tightened down in a fixed position, rather, it is held at the proper tension at all times by the spring, so it is free to adjust over the life of the belt,from cold to hot, etc.. this makes it real easy to loosen the belt as described and remove the belt...mind your fingers by the alternator pulley if you slip with the socket and the belt pulls tight...ouch. There is nothing scary about it, the belt tension is not really all that tight, it just feels tough if you use a short wrench or start at the wrong angle..lying on the ground, use a long handle socket wrench at 6 or 5 o'clock a steady counterclockwise push...like butta.
Still on the ground in front, the alternator is secured from the front only by Two bolts, a big long through bolt on top - 8mm allen socket, and a 13 mm short bolt at the 3 o'clock position when viewed from the front. Mine was practically welded in there and took a bit of wrestling to break free - a two hand grab and rock it back and forth affair, maybe a flat pry bar, but be mindful of what you are prying on and against.
Remove the Oil Cooler Assembly. Start of the soul trying tricky bit...remove the electrical plug to the oil pressure sender - a light squeeze with a pliers ought to do it, unscrew the sender - 21 or 22mm open end wrench, remove the five 8mm allen head bolts securing the cooler to the block, remove from below, mount the unit in a vise clamping the alternator bracket ear lightly in the jaws so that the matrix is facing the ceiling,remove the five torx (T25 I think??) screws holding the cooler matrix in place, clean up mating surfaces, replace the gaskets and reverse the process. Ha! If only it were that easy.
Getting the five 8mm allen head bolts out was a bear - 2 from below 3 from above. Of the two bottom bolts, the shorter one is toward the back of the car and is slightly obstructed by the top of the oil filter housing. I found that a LONG allen key was the trick to getting this one out..others have had success with wobbly sockets and the like.
Before starting any of these bolts, I inserted the allen key and then gave the back of the key a medium firm tap with a hammer to fully seat the key (and maybe shock the thresds a little...doubt it)...It is a two hand job: press the key inward with one hand while turning with the other, keep the misalignment to a minimum or you will pop out and risk rounding out the bolt head. The bottom front bolt was pretty easy with an 8mm socket wrench and a variety of extensions and a wobbly head adapter. Again, keep misalignment to a minimum and maintain steady inward pressure to prevent the key from popping out and stripping the bolt head. The top front bolt is another simple one. The middle one is blind, but still a pretty straight shot over the top of the external metal coolant pipe which comes from the back of the engine.
Said metal coolant pipe is secured to the oil cooler body with a single 10 mm bolt. I could not see how to remove the back of this pipe from the back of the engine and by Always Overcharged's account, it is a real bitch to do so. I am lazy. So, instead, I pulled it out of the oil cooler and it had enough slack to move out of the way to get the cooler out from below.
This pipe is really seated into the oil cooler body. I pulled, pryed, wiggled and tugged on it without much success, then I used a steering wheel puller with just the center bolt, slid an ear under the pipe and slowly tensioned the bolt and then it started to budge, continued pulling, prying, etc and it finally popped free. It has a rubber "O" ring which you will also replace. I must also confess to pulling on this pipe with a vise grips, you cringe, but it worked. Had it actually gotten ugly, I would have cut the pipe in half and then twisted it out of ther cooler body and then spliced it back together with hose and hose clamps later. It didn't quite come to that.
The top rear 8 mm allen head bolt tries mens' souls. It is blind, it is tight, and you've got no damned room to manuever. You can see the bolt head... barely...while lying under the car but you can't get the wrench in from below. You can slide the extension bar in from above, but you can't see squat...blind retard wrenching at its finest..an assistant lying under the car giving directions while you try and find the bolt from above would make it easier...maybe. Right about then I was thinking I really should have called Heinz, but there was only one 6 pack of Heiniken and I was fierce thirsty. Scratch one able bodied assistant. Wait, that didn't sound right.
If I had it to do over again, and I pray I don't, I would suggest buying the following items..several identical long 8mm hex keys and several 8 mm sockets. Cut the short head off one key so you are left with a long straight key and then cut the next two keys shorter in...say.. one inch increments and hotglue each one into one of the 8mm sockets. A long naked allen key is much skinnier than an extension bar and can get into tighter spots, the socket makes it easier to turn, but since the space is soooo tight, once you start to loosen a bolt, you need to switch to the next shorter homemade allen socket so you have clearance at the back of the wrench. It really is that cramped. Once you get it out, take hope, getting it out is the hardest part...but only by a little.
Now you've got it out of the car, remove the cooler matrix. I like a torx bit on a long extension bar with a socket wrench. This way you can push down with one hand while applying firm steady pressure on the wrench with the other. All 5 torx bolts came out unscathed this way...thanks to Always Overcharged for the heads up about these bolts, he was not so lucky. So, the extra effort here - mount it in a vise at the big alternator bolt contact points, and steady downward pressure with one hand and loosening pressure with the other - made it easy.
The unit will go back into the car without jacking on the engine block with loosened motor mounts or any other shennanigans, but it will only go in one right way and there are many wrong ways to try. Hard to describe, but if you are under the car and get stuck, read this and you will see what I mean. If you get it into the space but the oil filter mount is tilted outward toward the frame rail, forget it, it is wrong, you will never get the filter housing to tilt down past the frame rail. Take it back out from below and try it with the top of the unit tilted away from the block and the bottom close to it. You may have to rotate it a little, but it will go in this way so un-freakin-believably easy that you will want to dance a jig. Both during removal and reinstallation, be mindful not to bash the fairly fragile matrix against the engine block. It would really suck if this thing sprung a leak.
When you bolt it back up, note that there are two locating dowels - top left and lower right - and the plastic pipe to line up. Tighten it down evenly. If you get it cocked too far out of alignment, the bolts will be a little harder to turn. If they do, loosen the last bolt you tightened by a turn or two and see if that helps. This is where you want to be patient, no rush, in your happy place. Another really bad time to strip or break something.
I didn't have my Bentley available for this procedure as I just switched computers so I don't know what if anything they add to the processs.
I still think doing the fuel pump is easier.
Regards,
Brian C.
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