2004 C4S aos replacement

Guys I need some help here.. I've been slowly trying to get this done and just ran into a wall. I am unable to get the coolant tank out. I dropped the engine down as much as I could and I broke the hanger that holds it and am still unable to get it out. I'm curious if dropping the engine would be easier (I've heard of people dropping the engine within a couple hours).. Really just wanna get this aos fixed up and get the car running.. If I would have known I would have these issues and it would take me this long I would have just had the dealer/Indy get the work done.. But now that I've got a bunch of stuff off I just want to get it finished.. I heard the newer cars have a bigger coolant tank and maybe that's why I'm having so many issues.. Anyone have any advice?

Yes, it's not an easy job on the MkIi due to the larger tank. If you slide the tank off it's black bracket and remove the bracket, that should give you a lot more room to wiggle the tank out. If the tank is hitting the fuel rail cap, you can remove that cap carefully (with a wrench countering below the cap).

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Let me know if you succeed, I will have to tackle this on my '04 C4S too.

Will try again for a bit tomorrow.. I figured the widebody car would be a bit easier but clearly not.. I did drop the engine a couple inches and still won't clear was unable to get one of the bottom hoses off (disconnected at the next location so there's about 4 inches of hose on the bottom connection.. I'll try a few more things tomorrow and let u know if I get it worked out.. All the diys I read made me think this was pretty doable (time consuming but doable).. Should have read a bit more into the mk2 cars.. Thanks and any other advice let me know..

Good luck! I have a cabriolet, so I guess mine will be even more difficult to access. Have you considered dropping the engine?

I have considered it yes.. Will see if I can't get the coolant tank removed today I may go that route.. Does anyone know how to remove the coolant tank plastic holder thing?

1/4” drive 10mm socket, 8-10” wobble extension, ratchet, patience Amazon Amazon

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There are two up side down screws holding it to the frame. Btw, I thought you wanted to replace the tank. That's not needed if you only want to replace the aos.

According to the diy that I read you need to remove the tank to get the driver side intake manifold off to access the aos?

On my 99 C2 I did not have to remove the coolant tank to replace my AOS. That being said, it certainly would have made things a bit more accessible, but then again, removing the coolant tank is a PITA job by itself. The AOS replacement with engine in the car is one of the worst PITA jobs I've ever done. I swore afterwards that if I ever need to do that again, the entire motor is coming out.

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There are many diy writeups and not all are accurate.

Some of the "instructions" do not apply to the C4S. Mki and MKII have significant differences too. A few tips: I'd take out the alternator, except I didn't. You need to remove the bolt at the end of the fuel rail for clearance. Last intake runner bolt (in the back) if a pain in the a$$. You will be able to turn the wrench about 5 degrees at a time, flip, turn again, etc. When you put the runner back in, tape the bolt in the hole - try not to lose it. Last thing, when I removed the AOS, I cut the body so I could remove the hoses after. Good luck, sh$tty job.

I too had trouble removing the coolant tank in my 04 C2 when replacing the AOS. I ended up leaving the coolant tank in place. My number one tip would be to buy a mini ratchet and the appropriate nut driver sockets. The one I used was perfect: Neiko 03044A ($9 on Amazon). You'll also want some bit extensions and the correct sized nut driver tips. Hex sockets worked fine for me on the reverse torx bolts. It seems there were a variety of fastener types used on different cars so just see what's on there. I used electrical tape to secure the extensions- it's a pain to retrieve anything from that area. A cheap magnet on a flexible shaft came in handy. Lower the engine as far as the motor mounts allow and you can reach the front AOS bolt from the wheelwell. All the manifold bolts and the rear AOS bolt can be reached using the mini ratchet and a combination of extensions. Only a few are difficult at all. Hose clamp wrenches make the coolant connections a lot easier. Connect the snap on corrugated AOS hoses before reinstalling the manifold. One of mine was cracked so I spent and extra week waiting on the part.

Well I removed the rear intake Plenum that gives a bit more space and tomorrow I am going to attempt to get it out.. If I can't then most likely I will drop the engine as this is a bit crazy to get out.. Another hour or 2 tomorrow as is (some connections from below/wheel well and some from the top.. If it doesn't work I will try and drop the engine.. Just seems like a lot of work.. But again if I drop the engine I know it will be done right..

Ok so I got the aos replaced.. I was able to remove the aos from thr top of the engine and attach the 2 or 3 lines to the top of the new one and feed it down where I then installed the bottom lines and buttoned everything up.. Had the coolant line in front of the engine break at the connector so rigged something up from napa and got everything buttoned back up.. Now the car won't start.. It turns but will not fire.. I rechecked the fuel line at the top and it was still connected and not leaking.. I went through and double checked everything before I put the alternator back on and was confident everything was hooked up properly.. Anyone have any ideas or where I should start?

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Check fuses C1-C4 and E1, then do e-gas calibration and retry.

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Just checked the above fuses c1-c4 and e1 all had continuity and I did the egas calibration (turned ignition to on for 60s I did 70s, then key to off for 10s I did 12s.. All this without touching any of the Pedals) I then attempted to start the car.. Same issue.. Engine turns but will not fire.. Any other ideas?

Next is check for vacuum leak (plenum rubber boots. airbox to throttle body boot) and make sure MAF and throttle body are plugged in. If you have Durametric, you should also scan for codes.

Did you at anytime unplug the CPS? Check your Crank Position Sensor and the electrical connector to it to make sure it is plugged in tight. When you crank it does the tach needle bounce?

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Good point. OP. does your tach needle bounce a bit while cranking?

Tach needle doesn't move at all during cranking.. I am pulling out my durameteic (I've never used it) and see if this gives me any other info (I figured since its not starting and giving cel it wouldn't help.. But will try right now)

Durameteic shows one code p0335 engine speed sensor signal - open circuit I guess this could be the issue?? Any ideas what/where to look from here?

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It is more than likely the CPS is either unplugged or somehow it got bumped while you did the AOS since the tach needle does not bounce while cranking. I would check all that first.

That is the code for the Crank Position Sensor. Either it is unplugged, loose electrical connector, or has failed.

DID you have both the Crank Position Sensor and the CAM Position Sensor both disconnected? IF so you could have pluged them into the wrong connector, They are close to each other and will physically cross. Even though they are color coded black and white, when they are dirty the distinction isn't so clear. Ask me how I know this (the hard way). And don't feel to bad if this is what has happened, I have seen many other people do this.

Issue was the CPS connector. I disconnected to install the lower hose and didn't re-install properly. Plugged her back in and it fired right up (idle was really struggling at first and a lot of smoke as it burnt off the residual oil in the intake system. Drove around for a bit and after a few mins I didn't notice any more smoke. The idle was acting weird at idle cold it would jump from 700-900 rpm.. when warm idle would be about 1100 and occasionally jump up to 1800 then back down to 1100. I believe this is most likely a vacuum leak somewhere. After about 20kms I took the car for a wash and then about 5kms later it popped a CEL and said to drive to workshop. I took her home and plugged in the Durametric and found a laundry list of codes. P0507- Idle air control at stop..Above limit P0300- Misfire detection P0306- Misfire, cylinder 6 P0302- Misfire, cylinder 2 P0303- Misfire, cylinder 3 P0305- Misfire, cylinder 5 P1126- Oxygen sensing adaptation, lower load range, Bank 1 I am heading on a business trip for the week. Hope to have some time this evening to look over some stuff but doubtful as my flight leaves at 6am tomorrow morning. Let me know if anyone has any suggestions or if we all believe its a vacuum leak somewhere. Thanks for all your help so far guys.