Community Review and Comment Please

Hello all: In November of 2021 I acquired a 2003 911 Carrera 4S from a dealer. Mileage showed 40,200 at purchase and I have added 1000 miles since. The car has no history of major problems, or any problems at all really except normal maintenance. She runs great. No oil drips, no strange noises, no smoke, and so forth. Maintenance items such as brake pads and tires, as well as the cabin, were up to date. But I will be bringing her into the local dealer next week for the following list of major/minor preventative maintenance actions. I am writing here to ask the community�s review and comment on this plan. What have I left out? What is overkill? My idea is to avoid any major issues in the coming years. So here is the list: 1. Install the LN upgrade IMSB 2. Replace the RMS 2. New clutch 4. New flywheel 5. Flush cooling system and renew antifreeze 6. Replace rear tires as one has a gouge in the wall probably due to a curb incident. I missed this when I closed on the car. Shame on me. 7. Change oil and filter 8. Renew spark plugs 9. Replace engine air filter 10. Replace cabin air filter 11. Balance 4 tires 12. Check alignment 13. Replace transmission fluid and front differential fluid 14. Change fuel filter 15. Clean up wheels and check for out of round/plane 16. Add 10 or 15 mm spacers in rear and 10 mm in front 17. Replace AOS 18. Replace oil drain plug with magnetic plug 19. For consideration: -replace cooling water pump -replace thermostat -inspect motor and transmission mounts and replace as needed -inspect oil cooler So that is what I have for now. I would appreciate your review and comment. Thanks Rick

I don't think anything on here is frivolous. I'd probably move water pump to mandatory unless there is a record of changing it. Congratulations on the purchase! Regarding IMS, are you going with the solution? What about AOS? UAOS or Porsche?

#6, #7, #11, and #12 I would leave the IMSB alone, as well as other major items you listed. Edit: #5 probably not a bad idea either

I'd do everything on your list including #19. And the AOS. I grew up around civilian sport aviation and had a career as a military aviator. I'm a big fan of preventative maintenance. Replace the things that have a high probability of failure before they fail. There's enough that will still go wrong on even the best maintained car (or aircraft). Overkill? Sometimes, maybe. But I sleep well at night knowing that I can go out to one of my cars, turn the key and go, w/out wondering what's going to break.

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Only thing I will challenge you on here is removal of the IMSB putting unnecessary stress on the motor. With the other items OP mentioned, you're probably right, but one thing I've learned owning many older German cars (only BMWs - this is my first Porsche), is that sometimes things are better off left alone, especially if they are working and working well, like OP's car as it sits now. It would be better if OP gave us a baseline of where he's at based on past maintenance and/or receipts.

A history record helps. But a good list. Go with the UAOS, worth the money and gives you peace of mind.

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Thank you for your thoughts. 1. Agree on water pump. Will do. 2. I think we are going with the LN replacement grade level. I had a brief discussion on this with the service manager and after kicking it around we settled on the replacement grade, primarily because they hadn't done a Solution grade to this point. Thanks again Rick

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Thanks for your thoughts. I think I understand your thinking. "If it ain't broke, don't fix it", right? Generally, that's the approach I use with the other cars in my stable at the moment. I'm religious about the normal maintenance like oil, tires, coolant, alignment, etc., but on components like a water pump, I just wait until it shows signs of imminent failure, then replace. And of course, they rarely fail, as I believe your thought might be. But I also know that if a water pump for example fails on my Grand Cherokee, I can have it replaced just about anywhere. Not so for our cars here. And there are some other contributing factors: 1. It's winter here and the Porsche will be in the garage for about 3 months anyway so I'm using this time to advantage. 2. We've had 3 good to excellent years in the market, so the liquidity is available to fund this endeavor. So what the heck! Thanks Rick

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Roger all. Thanks Rick

I�ve owned my 996 for a year and a half and have done everything on your list except #16 spacers. Spacers aren�t preventative maintenance. Also I went with the IMS Solution instead of the �upgraded� IMSB Plus I�ve also done: FUEL INJECTORS (very important imo) Water pump Low temp thermostat Flush clutch and brake fluid Updated coil packs Timing chain tensioners Serpentine belt, rollers and tensioner

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Thanks for your comments h. Unfortunately I have no record except CarFax on the maintenance history. I have been calling the Porsche dealers mentioned on the CarFax to see what I can find out. They have been very cooperative but so far I haven't found much. Replacing the battery about the most significant. Otherwise oil changes, tires, alignments. No major or even minor surgery. But there was no record of antifreeze replacement, brake fluid. Also this car has been a bit of a hanger queen over her life. 10 years after purchase the car only had 15,000 on the clock. Then the next 4 years only 12,000 additional were clocked. Then 13,000 until sale to me. I'm very interested on your thinking on the IMSB. The reason that I want to get it done is so I won't need to worry about it for years. And it can destroy the engine if it fails catastrophically. And I admit to being paranoid about it. I am interested in your reasoning that replacing it could result in "...unnecessary stress on the motor..." In what way? Thanks again Rick

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Roger on the record. I don't have much. Unfortunately I have no record except CarFax on the maintenance history. I have been calling the Porsche dealers mentioned on the CarFax to see what I can find out. They have been very cooperative but so far I haven't found much. Replacing the battery about the most significant. Otherwise oil changes, tires, alignments. No major or even minor surgery. But there was no record of antifreeze replacement, brake fluid. Also this car has been a bit of a hanger queen over her life. 10 years after purchase the car only had 15,000 on the clock. Then the next 4 years only 12,000 additional were clocked. Then 13,000 until sale to me. I like the UAOS so I will discuss that with the service guys and see what they say. I'm reluctant to twist an arm to have them do something for the first time. We'll see. Thanks again, Rick

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Thank you Phil. Great comments. I have thought about the injectors. Do you know how one would go about evaluating them? Start up? Highway driving? Gas mileage? Ugly looking exhaust? This car really runs smooth, starts right up, no smoke. Are there more than one thermostat? We did the brake fluid when we did the PPI. I thought about the serpentine belt also, having had one fail on my first Maxima. I believe the Porsche guidance is 60,000 miles on the belt, and I am at 41xxx. Thanks Rick

Great list! But 14. Change fuel filter, the 996.2 doesn't have a replaceable fuel filter, just the 996.1.

The injectors are 20+ years old so it�s probably best to just replace them. I believe the consensus among the 996 community is to go with the LN Engineering low temperature thermostat.

I like your list plus: water pump/thermostat. If the water pump fails catastrophically it could destroy your engine block. You don't want that. fuel injectors. Renew them they have eaten a lot of water and crap in 41,000 miles. Go with new not "rebuilt". Leaking injectors contribute to bore scoring. coils. Change them. If not cracked now they will be soon. spin on oil filter adapter. Makes changing filter easier and eliminates the crappy check valve in the bottom of the OEM plastic can. engine mounts. Change them. Cheap and easy. opinion: do the IMSB while the other work is being done...period. I recommend The Solution, but your dollar. Another thing that if it does fail it is something you don't want.

Rick, your lists and everyone else's are solid. Remember, you own a 2003 not a 1998, so you gotta replace the IMSB. Your call on the Retro or Solution. Both are exceptional products. retro will need to replaced again. Solution won't. Do yourself a favor and replace the ignition coils and fuel injectors when you do your spark plugs, as well as replace your MAF. You will save yourself a few headaches with CELs that will eventually pop up. Go with the UAOS. Don't waste your time and money on the stock AOS. Lastly, if you want to eliminate any concern over bore scoring, get it scoped. Yep, it will be a pricy service, but if you do everything on your list and the other items mentioned by the guys, and assuming your bores are good, and you change your oil at least 2x a year and test it, you will have a keeper that you can rely on.

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Good catch. Thanks Rick

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Wilco. On the list. Thanks

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Billy Thanks for your comments. Water pump/thermostat now on the list. Injectors now on list. Engine mounts now on list. Coils probably, depending on $$$. $80/per on Pelican. Yes, the plan is to do the IMSB and all the other stuff in the same visit. Might take 2 weeks. I will be discussing this with the service manager this week. Rick

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Thanks GC for your comments. It looks like the MAF is a logical replacement along with injectors, plugs, and coils. I am beginning to think that I will need to prioritize my list though into 2 separate availabilities. The service guy may choke on all these items for 1 visit. Maybe we will do everything that benefits from the transmission being dropped and the motor stuff in a second visit. Rick

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Absolutely makes sense. Just group things together that will save you money on time. It's the "while you are in there but don't go any further" approach. Been doing it for years.

Your list is good and you�ve generally been given good guidance from the others. I don�t think you�ll hear a lot of support for the one suggestion to leave the IMSB alone though. With the low miles, I�d consider doing the IMS solution. If the flywheel is good, I don�t see much sense in replacing it. Before you drop all this coin, please make sure to do an invasive inspection, including bore scoping. Look at the images yourself. Trust but verify what your mechanic tells you. You don�t want to drop $7-10k only to find that you have bore scoring.

I'm in the process of doing most of the same myself. Add the serpentine belt with the water pump and low-temp themostat Replace the power steering fluid Inspect all fuel, brake, coolant lines/hoses and replace as needed. I can't recall if you had this on your list but an alignment. This is the maintenace schedule from our mechanic. 5,000 Engine Oil & Filter 15,000 Cabin Filter 30,000 Spark Plugs 30,000 Air Filter 30,000 Fuel Filter 30,000 Power Steering Fluid 48,000 Water pump, thermostat (or every 4 years) 48,000 Serpantine Belt (or every 4 years) 60,000 Transmission Fluid 90,000 Spark Plug Tubes 120,000 Fuel Hoses 120,000 Coolant Hose Annual Brake Fluid Flush Bi-Annual Coolant Flush If you track the car, you may want to modify this schedule. Enjoy.

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Thank you B. No track for sure. I doubt this car will ever reach 7000 RPM by me 6000 though. The inspections you mentioned were done during the PPI. I probably should do the serpentine belt even at 41xxx, but 19 years. Rick

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This ^^ IMHO you should have the car thoroughly inspected before investing time and money into it. That�s why I�m a big supporter of the IMS Solution certified installer program. Once it passed the certification I knew that my 996 had a solid foundation before doing any work. If it failed I would have altered my plan.

I believe the belt (and water pump) are 48k or every 4 years, so probably a great idea!

I think if you are serious about this and have limited service info on what's been done on an "older" car, then most if not all of these maintenance items are worth doing. At least you can check of the list and know what's been done. I replaced my water pump and found its been done at some point, but who knows when. I can at least show with receipts and other paperwork from when I bought it, what I've done. I have a ways to go on this list, but keep chipping away.

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So here is an in situ look at the IMS cover plate.....more to come

Here is a better look at the IMS and rear main. Also dropped the oil pan today and no foreign material in the pan. Only oil.

Just got my 2001 in late November. Due to a few tiny specs of metal in the filter, I decided before I even drove it to have a major service done. I did everything that required the motor to be out to do, as I had no record of it ever being out of the car. It cost me, but I am glad I did it. While talking to two or three people who have owned a lot of 996 cars, I had a long discussion about doing the sump baffle, UAOS and the low temp thermostat. They all echo'd the same advice. If you are not tracking the car (yeah, once or twice for a fun run it OK), running mainly on the street, then there is really no benefit to doing any of those three. A replacement AOS should be good for quite a while (mine, after 56,XXX miles) was still in excellent shape, but I replaced it as a precaution. I drive 99% of the time on the street, in all weather, so a low temp thermostat was NOT recommended. As for the sump baffle, that is a nice upgrade and, as funds permit, I may be inclined to do that, but it is not a necessity. I have summer tires to purchase and some other things I want to take care of before I spend $$$ on that. I did notice no mention of plug boots. Two of mine were leaking, so I did them all This is just part of my early education into the P-Car world, your advise from other may vary.

Hmmm. Will check on the plug boots. Thanks

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Is this a plug boot?

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That's a coilpack. I think he meant spark plug tube. Those have o-rings that can be replaced.

I believe spark plug tubes only came in engines in earlier .1 cars. A C4S being a .2 car does not have those. While the engine is out and fluids drained, I'd have them replace the 2 O rings that seal the heat exchanger connections. Those can leak and would be a super easy swap right now.

Hi All: Well, my car has been sequestered at the dealer for 3 weeks while the work was being done. But safe and sound in a super clean environment being worked on by competent people. we ended up dropping the engine and transmission as it made most of the work items much easier due to access. Before dropping the engine the oil sump was removed and inspected for debris, metal or other. Nothing was found. While all this work was being done, many photographs and videos were recorded. So here is what we accomplished: 1. Replaced IMSB with LN retrofit version (not "Solution") 2. Replaced rear main oil seal 2. Replaced clutch 3. Replaced flywheel 4. Checked and reset engine timing where necessary 5. Checked and adjusted 4 wheel alignment 6. Replaced and balanced 2 rear tires 7. Balanced 2 front tires 8. Refinished 4 wheels 9. Flushed cooling system and replaced anti-freeze 10. Changed oil and filter. Added M1 0-40 synthetic 11. Replace spark plugs and ignition coils 12. Replaced engine and cabin air filters 13. Replaced AOS 14. Replaced fuel injectors 15. Replaced water pump 16. Replaced thermostat 17. Replaced cooling water surge tank 18. Replaced serpentine belt and all rollers 19. Replaced engine mounts 20. Inspected MAF sensor-not replaced I was very pleased throughout with the competence and courtesy of the staff including the techs and manager. I was in about once a week to check on progress and they were extremely courteous in reviewing the work, showing me the old and replacement parts, and their approach to the work. As well as sending pictures and videos by email. I highly recommend this dealer. The techs have done an extensive road test, and my turn is tomorrow. Rick

I'm curious on the fuel injectors did they use the Porsche branded ones that are about 10x the price of Bosch. It being a dealer I wondered if they use non Porsche branded parts. I know the Bosch are hard to get now.

@Lady Silver just curious, did you ask them to keep the old parts? I have serious trust issues with mechanics and yes, even dealers, but sounds like you're having quite an inclusive experience (which is good...)

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As I understood Hartec of England's position; replacement IMSBs have a thin bearing shell which can be distorted during installation and have a greater chance of failure than an original undisturbed one. In our 996.2 we have the highest rate of failure factory IMSB (single-row) with 120k miles, and are leaving it in place until we do an elective overhaul at hopefully 180k or so miles. If we were changing AOS I would replace coolant tank at same time because we had the intake manifold off and that would have made replacement vastly easier. We had crank position sensor and fuel pump relay fail, so would change both of those low-cost but necessary to keep from being stranded items.

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They offered all the old parts to me but the only ones I kept were the plugs and the IMSB. I did inspect everything that came out, and the new parts that went in as the engine was sitting on a stand and I went in to visit a couple times a week. And yes, this was a singularly great experience with this dealer

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Yes the tech suggested swapping out the coolant tank as they do fail and it was sitting there with easy access as the engine was on the stand.

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I'm pretty sure they used the Porsche sourced injectors. Will check later today.

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I wanted to get back on this. Definitely Porsche branded, around $300 each.

Pricey... but if it fits your budget and comfort level then good 4 u. im cheap and dont trust anyone

Right you are. As I mentioned in another thread, Porsche is an expensive car, with needed and expensive maintenance. I was well aware of that when I came back in. So I was prepared for it. Some guys can DIY, and that's great. But, in my experience, BMWs, 'Vettes, Z28s, when you put your foot down there's nothing like it......