996 Carrera 4S Engine Removal and Refresh

I wrote this a few months back for another forum while doing a minor engine-out refresh of my 2004 Carrera 4S. I thought I�d post it here in in case it provides some support � not so much technical, but emotional � for anyone thinking of tackling the same thing. My car has a lot of small issues and leaks, all that require removing the engine and transmission to remedy. German engineering at its finest. I also can barely afford to keep this thing maintained, so to help with that I do all of my own work on it. After a few months of gathering the needed cash and parts, I've started at it today. Tools: All of them - Not a good sign. $200 worth of fluids and more on the way. This car takes around 8.5-12L of oil, depending on who you ask. I was here, once. I need around 29 inches of clearance at the back in order to slide the engine out once it's dropped. That requires adding some cribbing under my tallest jack stands (3-leg Harbor Freight Esco knock-offs). If you try to shake the car it will sway a bit, but it's a sturdy sway. I hope. Removing all of the underbody shields (already removed in this photo). They serve an aerodynamic purpose, but also protect all of the things underneath the car. Mechanics are notorious for disposing of these because they're a pain to take on and off. By detaching the AC compressor and leaving it in the car, I avoid having to have the AC recharged when I'm done. This is a huge pain in the ***, because things inside the engine bay are tight - not just at the opening, but this horizontally-opposed engine is really stuffed tightly in there. An inspection camera isn't necessary, but it's a huge help in finding all of the hidden bolts. Bag & Tag. Everything gets labeled to aid in reassembly. Finally got er out. Only cost me a bloody finger. Now onto the whole trusting mechanics part. The book is telling me to remove an aluminum suspension crossmember. Seems like a pretty important part, right? Well I go underneath to grab it, and nothing's there. At some point during the previous ownership, somebody forgot to put it back on. So I've been driving around 35k miles without this necessary bracing. Anyways, that's as far as I was able to get this afternoon and will update with more progress tomorrow, whether you want to see it or not.

I woke up this morning and headed back to Horrible Freight. My original plan was to grab a transmission jack to support the transmission and a motorcycle jack to support the engine - but then I saw this. 1000lb capacity hydraulic lift table. It just so happens that my motor and trans combined weighs just under 1000lbs. Assembled, bled, and tested. Supporting the motor. Grunting noises. ...and it's out. The cool thing about this is I can lift the table back up to work on it. Also the slave cylinder piston fell out. This will be a problem for reassembly. The next step is to document all of the areas where it's leaking before giving it a thorough cleaning, then tackling all of the little issues one by one. I figure it will be about two weeks before I'm ready to put it back in.

I dropped a bolt into the engine and thought I was done for. Cracking the case open to retrieve it is beyond my ability and budget. Then I remembered my inspection camera has a magnetic attachment. I found it. I can't believe I found the ****ing thing. AOS hose split just by touching it. Good thing that's on the list of things to replace! Intake manifolds off. This gives you a nice reference for all of the AOS plumbing. An Oatey 2" (50MM) Gripper plug fits perfectly into the oil filler tube hole and helps prevent dropping bolts down into the case. My shop interns. Anyways, I've removed the intake, alternator, and steering pump. Identified where things are leaking and what brittle hoses are cracking. Ordered another $500 in tiny parts, hoses, and seals, and now it's time to set it aside and wait for them to arrive.If this thing ever runs again (I assume the worst) I'm really going to feel like I've earned it.

Nothing too exciting to report, aside from waiting min parts orders that trickle in everyday. Always want to grab something immediately, then eat the shipping charges when I remember something an hour later. At this rate I should have the parts together and possibly back together by the 15th. I got this timing tool. It's not as precise as checking with the computer, but I'm trying to avoid buying a windows laptop and special software just for my car. This at least gives me confidence it didn't jump a tooth. When the first piston is at top dead-center, the slots on the cams should line up so that this cam-locking tool can fit in both slots. This connects to the alternator. Gotta figure out what to do with it. Leave it, glob some hot glue onto it, liquid electrical tape, or de-pin it and re-crimp. These aren't adapters, but are short little extensions for when a short socket is too long and a long is too short. Finally got a parallel/ratcheting tool for these clamps. Had been using the plier style but the extra leverage really gives it that last squeeze it needs. The nice things about this style clamp is it doesn't bite / cheese-grate the hose. Partially reassembled. I changed out those pulley bolts to match. Guibo / aka flex disc. This couples the main differential with the driveshaft going to the front wheels. Mine's not too bad but pretty cracked up and I might as well change it while I'm in there. That's been a bad theme on this project and has added about an extra $2k in parts expenses. This O-ring is seemingly too thick for the fitting it needs to mate with. My old fitting didn't have an o-ring there and it connected firmly - yet my old one also leaked. Will have to do more research but will eventually force it on. New hose on the left, old hose on the right, also on the right is a section of hose I wasn't supposed to cut off, that I cut off. Cheap enough mistake, but then add shipping costs plus waiting time and each mistake becomes really annoying. Test-fitting which fastener and wrench type would work best for doing this AOS job with the engine in-car. Going to change out the original E-torx head bolts for something simpler like an 8mm hex head. Something you can use thinner wrenches on. Factory O2 sensors are around $150 but you can get the exact same ones for $50 if you reuse your old connectors. I hate spring clamps with a passion, but this car has a lot and I can't replace them all. So I picked up these. They're based on the standard Knipex Cobra but with swiveling tips on the jaws to grab ahold of the spring tabs. They also have a locking lever to keep the clamp open. They make clamping fun! Here's another set of my favorite pliers. These are hose-grip pliers and are meant for, well, gripping hoses. That's great and all but what I really bought them for is to release the tabs on electrical connectors.​​​​​​​ Especially old ones packed with dirt and grease. Also picked up these Raptors to help retrieve a slightly stripped oil fill plug on the front differential. Proxxon rotator ratchet. This one's got a really neat trick and if you're lucky I'll make a video. It acts like a normal ratchet, except you can twist the handle like a screwdriver in tight situations to forward or reverse the ratcheting mechanism. ​​​​​​​And finally I picked up a digital torque wrench in the hopes that the ease of setting it will promote its use. You'd think stripping an aluminum block would encourage it but no.

Here she is in all of her flawed glory, just waiting on an air-oil-separator and I can start the process of putting it back in. The plan is to begin on Monday when the part arrives, and hopefully have the car back up and running on Tuesday. It would be earlier, but I originally bought an aftermarket version of the part and then second guessed it because of the work involved installing it. So I have a proper Porsche sourced one coming. My fastener board where I staple bagged and labeled small items. The area beyond that yellow thing hanging is no-man's-land where garage guests are not permitted. Mostly because that car is full of raccoon poop. Interesting that the wiring harness uses a Mercedes part for the throttle body, I broke this connector and am going to try and re-pin the wires in a new one. The special-order sport exhausts have a problem where a baffle comes loose in the muffler and causes a horrible racket. New units are no longer available - you can buy the standard mufflers and modify them, but it's hard to get somebody who knows what they're doing and is willing to do the work. I cut this one open and fixed the baffle myself, but the dual-layer stainless steel was a bit more than my welding skills could manage. I did what I could and spent about $50 in extreme heat JB Weld making sure it was sealed up properly. It looks like **** but nobody's going to see it. When I have some extra cash I'm going to replace the mufflers. I previously put some UV dye in my coolant tank in an attempt to track down an old coolant leak. What a mess. I used too much dye to begin with, then it clumps on the surface and makes you think you have oil mixed in with your coolant. To top it off, it's impossible to rinse it out of the coolant reservoir. Little furry helper spotted. This book contains the torque values of every fastener on this car and has been an invaluable resource.

[Image-only post; no author-written text. Original image references:] https://i.rdrama.net/images/17125365191846147.webp

Got everything put back together and running - then it started spilling oil out between the engine and transmission. I must've installed the rear main seal wrong. I replaced it, reassembled the engine, put the engine back in the car, spent two days hooking it back up - and the rear main seal gushes like a broken water main. What this means is I have to remove the engine and transmission and do everything over again. My question is, is there some way to test the seal before reinstalling the engine? It sits higher in the block than the sump, so the leaks won't occur until everything is running and splashing around in there. My thought is to replace it, then hang the motor tilted face-down overnight and see if anything drips out. Just hoping that won't cause any other issues. Anyways, rewinding a bit... I cleaned up my motor mounts and swapped out the stiff bushings for some softer ones. Jake Ray, who does a lot of research on these motors discovered that if you have too stiff of mounts you'll end up triggering the anti-knock sensors. (I'll later end up swapping these out for factory mounts) I love how these hose clamps come pre-cocked with a disposable holder. Here you can see just how little clearance there is between the frame and the top of the motor when removing and installing it. Watching the eclipse from under the car. Cool eclipse shadows but no time to sit and watch - I have a car to reassemble! The articulating Bosch Flexiclick driver comes in handy spinning new fasteners in. Just wish they had an impact version. At this point I was putting the engine back in without separating the transmission and without addressing the rear main seal. Once I got it in though I discovered I'd misaligned the clutch slave cylinder and blew it out in the process. That meant removing the engine again. At that point I decided I'd tackle the clutch and rear main seal while in there. Note the oil cooler above left. I ordered new o-rings for it and initially thought I'd ordered the wrong size as they were much thinner than the ones in there. Turns out the ones in there had swollen so much from use that they were no longer the correct size. These bell housing bolts are all different sizes, so once again it's important to mark everything. Separating the motor and transmission. I used an engine hoist to support the transmission. The circle in the center is the crankshaft, surrounded by the rear main seal. Below that is the IMS bearing, which is one of the Achilles heels of this motor. While it looks like the IMS is leaking, from my inspection it seems like it's just oil dripping down from the RMS. Cleaned up. Installing the new seal (Turns out I installed it with the lip facing backwards the first time). I picked up this tool for $100 on Amazon. The "Official" tool is like $500 from Porsche, and tons of people had just as much luck using the one I did. New clutch friction plate. Left the old pressure plate and flywheel in since they weren't very worn at only 57k miles. Lining the engine and transmission up and pressing them back together was a huge pain. I picked up this Motive Power Bleeder to do the clutch hydraulics and it made bleeding the clutch an easy, less than five minute job. Using my hydraulic ram kit to get the transmission lined up with the chassis just right. Sometimes extraordinary work requires extraordinary measures. Vacuum filling the coolant. This tool removes all of the air from the cooling system and then uses the vacuum pressure created to suck the coolant into the system without any air gaps. The one in the foreground is Brenda. She's around 11 years old. I always feared this would happen using a segmented cutting disc. Thankfully my Metabo grinder has a safety clutch. Pounding out old, rusty studs to replace with bolts. Putting the aforementioned rotator ratchet to use. Testing the crankcase pressure to make sure the AOS is working properly.

Not much to say except for I put it all together and it's running again. Somehow messed up the throwout bearing when reinstalling the clutch. It's making a whirring noise but I'm hoping to wait til fall to replace it. Needs an alignment since taking the engine out messes up the geometry of the rear end. Also found out why I wasn't getting a signal from the MAF sensor. It was a bent pin on the plug, not the sensor itself. Here it is all cozy and feeling healthy with its sibling. Rear suspension for the Volvo comes on Wednesday but until I get working on that I'm really enjoying having both cars being fully functional - a goal of mine when I decided to narrow down the fleet. All-in it cost me about $4.5k in parts and likely double if I had a shop do it. Insurance for the next six months is $675. Blue book on the car is $35-38k although they've been selling in the low to mid 40s this past year. Just to give you an idea of what to expect maintenance wise on a “cheap” Porsche.

100% on the vacuum fill. It's peace of mind. I never have to worry about air gaps. Thanks for sharing. I had no idea this could be done without a lift!

Did the RMS tool put the seal flush with the case, or recessed? I've got an 04 base that is getting a similar once over come the holidays this winter...... starting to gather the parts. Thank you very much for the post. -Eric 04 996 99 986

Quotes source post: 19650779

Recessed just the right amount. It�s been around 4000 miles since I did this work and it hasn�t leaked a drop.

Coming from BMW-land, and re-engineering those to be easy (engine out in 60-90min) this looks like I'm not cut out for it. Thanks for posting the process nonetheless, what an effort.

Quotes source post: 19650824

It�s tedious but doable. I�ve never pulled an engine out before this so I have nothing to compare it to.

Cute interns! I have exact same c4s except the color. I will be dropping the engine around November to replace the guides and chains. I found inspiration in your use of wood blocks to increase the height of the jacks! This was my biggest worry so far was clearance 😅. Will need to get same harbor lift for the engine/transmission. I even have similar borescope. I wonder if I should pay Porsche to check my pre and post cam deviation or just pay for a basis durametric kit. I think I should be able to install a virtual windows system in my MacBook and use the durametric software.

Great thread. Do you remember if you were in neutral, 1sf, or reverse when you dropped the engine/trans?

Great job on everything! Really good call on the O2 sensors, since they are the same for pre and post cat. I also purchased the ones without plugs and moved the connectors over. When doing the exhaust I always replace the studs with high grade stainless steel bolts and nuts and use anti-seize. This was super useful on the muffler attachment points and made pulling them off in future a breeze.

What an excellent write up.

Thanks for taking the time to post all of the photos and details. Well done!

Neutral.

Quotes source post: 20543638

Why do you have a garage full of raccoons? Maybe OK, but not to fpoop in another "car project". Curious. YRMV

Would you mind sharing the vacuum fill system you used for the coolant?

What book did you use?

Quotes source post: 20545095

Harbor Freight Maddox set.

Quotes source post: 20546452

I just used the Pelican Parts tutorial.