After doing the crack pipe and t-stat housing on my car, I found the 12v and 24v were different enough that it might be worth it to some to have a 24v-specific DIY. The biggest difference is you don't have to mess with the SAI pump - it's not in the way at all on the 24v
Based on my experience, I'd suggest either working with the car on the ground (if you can get under it enough to disconnect / reconnect the lower radiator hose. If not, put it on jack stands at the lowest possible height - you don't need much access underneath, and you won't have much flexibility to maneuver the lock carrier once you have it freed up. After doing the 12v last year and 24 this year, the 12v definitely had more flexibility to swing the lock carrier out of the way. The lower you are to the ground, the better you can maneuver it.
That said, I didn't do all these steps in the order presented, but if I were to do it again, I would follow this process:
Step 1 - Follow the lock carrier DIY (Extreme Version) - props to darisd for the DIY
Note: At step 7, the 24v (or at least mine) did not have the drain valve near the lower radiator hose. You will need to remove the splash guard, which runs from about the lower radiator hose to the control arm. It is secured by two snap rings and one torx screw. Also, instead of removing the lower rad hose as shown in Step 7, I simply pulled the hose connection - much easier than the connection shown IMHO. I also used a plastic under-bed storage bing (with wheels) for a large catch area for spillage - it works very nicely for keeping the mess to a minimum.
Note: At step 14, you will also need to disconnect the clip around the lower coolant line. This clip is at the approximate center of the bumper - I didn't realize it was there until I went to pull the carrier It's most easily seen in this picture:
Now that the lock carrier is down, it's on to the remainder of the job:
Step 1: Disconnect the air hose (yellow arrow) running along the side of the intake manifold and remove it from the clip (red arrow).
Step 2: Disconnect hoses the hoses from the t-stat housing. You will have more spillage with each one, so position your drain pan accordingly. It'll go all over no matter what you do
Step 3: Disconnect the hose from the crack pipe to the oil cooler. The spring clip on this hose was a huge pain to get at because of the orientation it was installed at from the factory. It was between sizes, or I would have put a screw-type hose clamp on it. I used a slip-joint plier to get in there, and that worked OK. For most others (lock carrier portion and step 2) I used arc-joint pliers.
Step 4: Disconnect the CTS (Coolant Temp Sensor / Green top sensor, or black if it's still the OEM sensor and somehow hasn't failed ). It's not has hard to get at as it look from this pic:
Step 5: Unscrew the two (2) long bolts securing the thermostat housing and bracket to the engine block. The bracket is the same one you unclip the air hose from in Step 1. Both bolts are 5mm hex head, and have a relatively short threaded section. After you remove those bolts, work the bracket out through the maze of hoses and wires.
Step 6: Unscrew the third 5mm hex bolt from the rear of the t-stat housing. It's short and it's buried in there, so you'll need a long extension. This one is much shorter.
Step 7: Pull the thermostat housing straight out off the block (more spillage will occur - position your drain pan beneath it). Most of the resistance will come from the o-ring at the end of the crack pipe, but it's not too bad.
Step 8: The alternator wire runs along, and is actually clipped to the crack pipe in two places. One is on the block side (see pic below) - you'll need to remove that clip in order to be able to pull the pipe through, so pull the wire out and remove the clip. The clip is secured to the pipe with a "peg" on the pipe - dislodge it from the peg and it'll rotate around so you can remove it. Don't worry about these clips or that wire - it does not need to be clipped to the pipe when reassembled.
There is a similar clip near the other end, next to the nipple for the oil cooler line) - just pull the wire out of it, you can pull the pipe through with the clip in place. Sorry - couldn't get a pic of that, but you'll see it.
Step 9: Pull the pipe out - it'll be REALLY tough to pull, but a bit of rotating while you pull will help. You can use the nipple for the oil cooler line for a little leverage in rotating, but it's somewhat fragile. I didn't break it this time, but I did on the 12v
Step 10: Check the hole in the block for corrosion or scale that might damage your new o-rings. It's a tight squeeze to reach back there, but you can do it. If there is, hit it with a little sand paper and follow up with a clean shop towel or rag.
Lube the end of your crack pipe/o-ring with a bit of coolant, or with the Gruven crack pipe (AND ONLY THE GRUVEN PIPE you can use WD-40 per Paul. WD-40 on OEM o-rings could result in deterioration of the o-rings, those supplied by Gruven are much tougher and more resistant.
When inserting the pipe, make sure you have it lined up with the drain valve pointing straight down and the nipple for the oil cooler line oriented appropriately. Push the pipe in, DO NOT ROTATE WHILE DOING SO. If you have it lined up right, it should pop right in.
Step 11: Prepare your new thermostat housing for installation. I didn't take any pics of this step, but it should be pretty straight forward. I'd recommend installing a new thermostat/thermo stat o-ring and thermostat cover. If you haven't already done so, install a green top coolant temp sensor (CTS). In my case, I already had one, but I got a second and put it in the other hole as a back-up for when the current one fails. All I'll need to do is swap the connector over - no mess
MAKE SURE YOU USE NEW O-rings and NEW CLIPS - they get brittle and aren't fun to get at once you've put it back together if it leaks.
The three 5mm hex bolts that secure the thermostat cover to the housing should all be torqued to 8 NM / 6 ft-lbs per the Bentley manual (it's 10 NM / 7 ft-lbs for 12v).
One last note on this - my original thermostat cover had an angled outlet pipe, the replacement I received was straight. ETKA only lists one part # - not specific to 24v, so I don't know how one would go about getting a proper replacement Unfortunately I didn't realize this difference until I was cleaning up after finishing the install. Fingers crossed hoping it holds - if I were doing it again, I'd re-use my original cover.
EDIT: for peace of mind, I pulled the housing back out and replaced the t-stat cover with the original. The correct part number is 021 121 121 E.
Pack the new gasket into the new thermostat housing and make sure it seats flush. Packing it with some RTV sealant isn't a bad idea, as it'll help hold it in place and help it seal when you bolt it up to the block.
Step 12: Push the new t-stat housing assembly into place. Like removal, most of the force needed will be to get it securely mounted on the crack pipe. Once that's done, grab the bracket and long bolts from Step 5. Work the bracket into position and put the bolt through. It'll take a little work to line them up and get them started. DO NOT TIGHTEN THEM ALL THE WAY YET.
Step 13: Insert the third bold to secure the rear of the thermostat housing. Once all three bolts are started, gradually work them down until they are all snugged up evenly. Torque spec is 8 Nm / 6 ft-lbs. If you don't do it evenly, it can affect the seal, which is the most important part.
Step 14: Reconnect the CTS harness before reconnecting any hoses - once this hoses are connected it'll be more difficult to access.
Step 15: Reconnect all hoses to the T-stat housing. I wish I had more screw-type hose clamps on hand to replace some more of the spring-clamps, but at least when you put it back together, you can leave the clamps such that they are actually accessible.
Step 16: Reconnect the oil cooler hose to the crack pipe. This especially is one I wish I could have replaced with a screw-clamp, but it was between sizes. I had one up to 5/8", and one down to 3/4". I'd say it's right about 3"4, but I wasn't comfortable using the larger of the two. Again, put it together such that the clamp is accessible.
Step 17: Reconnect the air hose next to the intake manifold, and clip it back into place.
Step 18: Lift the lock carrier back into position (resting on the frame rails. Reconnect the upper and lower radiator hoses, and clip the lower coolant line back to the front clip (from Step 14 of the lock carrier removal).
Step 19: Secure the lock carrier in the reverse of the removal (per the DIY linked above).
I left it there as I had other work I planned for the next day (today). Comments, critiques, suggestions, and questions welcome. All told, it took about 7 hours of work, and I'm not fast. If you've got skills, It could probably be done in half that As I think of additions or get feedback, I'll update the DIY accordingly
Modified by Veedub_junky at 7:52 PM 10-26-2008
Modified by Veedub_junky at 8:22 PM 10-27-2008