Plugs/Coils.....when to change

My 99/996 C2 has 62k miles. While I have it up for front end rework I pulled a few plugs and coils. To my knowledge they are original (?). See pics, the tops of the coils, when cleaned up dont show any signs of cracking all look like the one in the pic. The sides of some down on the mounting base show some hairline cracks.....one connector has a split. I have no trouble codes, it doesnt seem to misfire but there are signs of aging. How do you know when to change? Same goes for the plugs...see pic, the manual says 60,000 miles. I have pretty good access and can reach all plugs and connectors with rear wheels off (and patience). The Tubi exhaust seems to have good clearance for this job. Note in one pic down the hole you can see the piston with the plug removed. There is a fair amount of deposits. Note also I thought I had a valve cover gasket leak but its the tube...only one is leaking but the picture down the other tube does show a few drops of oil at the bottom. Any advice on when to change the tubes? As needed? All at once? Thanks!

I ended up changing all of my coils at around 55k. One started misfiring and when I replaced that one I had others start to act up. I figured I may as well solve the problem once and for all. I've put 60k on them since replacement and they still seem fine. The oil rings/tubes are fairly simple to replace if you have good access. I had two leaking at around 100k so I replaced them all. -Shawn

Good pics Jackstand Louie. I am at the same mileage as you with my 99 coupe, and am ready to change plugs and some plug tubes/o-rings, but don't plan to replace coilpacks because there are no running issues or CELs. I have some new small oil weeps that hopefully will be cured with new tubes and rings.

I would certainly replace the plugs. Changing all the coils is somewhat expensive and not really necessary if you don't have any problems. I ordered 3 coils from an online Porsche dealer for the "just in case" event that I would have an error code related to the coils. My coils are original, I drive my car all year (including salt/snow/ice covered roads) and I have yet to have any issues with the OE coils.

FWIW, I had the major 60K service completed on my '99 at 62K miles this spring. Then the coils still looked fine, and even the original plugs didn't look all that bad. As one spark plug tube was leaking, I had all 6 replaced (parts+labor = $130). My cab is a daily driver, too...weather permitting, of course. relinuca

Is changing the plugs and coils a DIY job? I'm a new p-car owner and I am trying to learn as much as possible. When I had the ppi done on my car the mechanic mentioned that one coil had a small crack and to keep an eye on it. There are now mis-fires or codes currently

Thanks all. I get no trouble codes at all so I'll probably replace plugs, connectors, and tubes (the cheap stuff). The coils are fairly accessible so I'll wait for failure. Anyone have a favorite plug? I like the design of the new Bosch plugs but no experience. Also, any suggestions on reducing those deposits on the piston top? I've heard Chevron w/Techron. Revn: I havent completed it yet but I did this exploratory to make sure I could get at everything. I'll report back. I did take out a few plugs in the hardest to get to locations. I have skinny arms and a lot of tools, the most useful being some extentions with universals. Different mulitple short extensions are good b/c you can piece them together as you take out the plug and put the new one in....your car may not have room for the whole straight assembly. I have heard stories about how difficult access is....mine may be different from stock since it has the Tubi exhaust and it seemsed to be radiused nicely around the plug area but still accessible. I may have to loosen one side to get the tubes out but by no means do I need to drop the exhaust or the engine. There are a few DIY's out there. To get to mine I have it on mid-level jackstands (already up for front end work) with the rear tires removed and worked from the wheel well. The forward two plugs on each side can be done from that location. The rear most plug required a combination of underneath (to get leverage on the ratchet for the plug) and working from the wheel well.

The oil drip is undoubtedly the tubes. It is a serious pain in the butt to get the tubes out (unless you have the tube puller thingy.) And if you crack a tube and pieces fall inside the engine ... well ... bad news. I wouldn't even bother with plugs and coils.

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If you have removed the plugs I'd replace them. They are original and while based on miles they may not be due to be replaced, they are probably due on time, unless Porsche has changed its plug change time interval. For coils handle them with care. If there were no misfires you can continue to leave the OE coils in service. For plugs why not just use the plugs that Porsche recommends? The OE plugs appeared to have served you well and the engine has never had any problems arising from plugs so why fix something that's not broke? Sincerely, Macster.

I just realized the same OEM plugs (made in France) are still available....Beru. Never hurts to check since those were OEM 12 years ago. So many companies get bought and changed (Chrysler bought Mercedes & Fiat, Audi bought Lamborgini, Ford bought Jag, the White House bought GM)

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Well, OEM does not necessarily mean OE (original equipment). There's some question/debate as to whether if one buys OEM he's getting the same quality of part as OE. I tend to use OE parts/supplies whenever possible. Even if the plugs are OE that was 12 years ago. In the meantime Porsche might have found a better plug and now recommends that plug. The advice I get from service managers is to get a part # (plugs in this case) based on the car's VIN. If you want to buy the parts (plugs) from the dealer's parts department or order/buy them from some other place that is up to you. The goal is to use the right plugs and ones that are at least as good as the plugs that were being used. Sincerely, Macster.

Everyone seems to agree on 60k miles for plugs, but a maintenance document I downloaded from Renntech shows different mileage for different years/models.

interesting. At 12 years and 62k I'm going for the change out especially since I have a leaking tube and two split connectors. 'minor' is a novel description. Special tube tool?? I've heard boat plugs are an option......my neighbor has a 30 foot Searay (out of the water)..the plugs caliper out about right.

Some people have suggested wrapping some sandpaper around the boat plug to help remove the tubes. My MY2000 is at 46,000 miles. I guess it's time.

The recommended plug change mileage/time might have changed. The dealer service department should have the latest info, unless -- and I do not know if this is the case or not -- if the info you obtained from renntech is the latest info. When discussing service intervals with techs and I have in mind a mileage number or a time in service and the techs disagree I ask for a copy of the latest service intervals and they oblige. Sincerely, Macster.

It's the document that is currently listed on RennTech under DIY Tools/ Maintenance Schedules / Carrera (996) MY98-05 I don't know if there is a newer version.

Removed plug tube with 3/4" SCH 40 fem socket x male thread adapter. Hand tight as far as possible, partial turn w/pliers till snug fit (dont overtighten..try loose and if it slips out tighten a little further) pry out slowly, gently with small screw driver on shoulder of PVC. Pops right out. This was leaking (inside and out). Does anyone know if the o-rings are flat like that when new? if not, I would think all of them look like this (two do, so far).

Great detail pics of your plug-tube extractor, clever. I went out and bought one, and just received 6 new plug tubes and o-rings, and 2 caliper brake vents(spares for bleeding brake fluid with my new Motive power bleeder). Still waiting for plugs and ATE super blue brake fluid, due in tomorrow. I've recently noticed minor oil weeping and I'm hoping they are from the spark plug tubes.Anyway, thanks for the simple removal tool.

My pleasure. One of my tubes was definitely leaking on the outside and down to the valve cover gasket. Now the gasket and seam are dry. About five of the internal o-rings were leaking some and leaving a puddle of oil near the spark plug. All dry now. All of the old o-rings were noticably flat, it was only a matter of time. You can use the PVC adapter to push the new tubes in if you need additional leverage. I flipped the adapter around so that the shoulder of the socket side fit nicely into the flange of the tube and used both hands to push on the male thread part to snap them in. Make sure you get enough grease on the inward side of the large (orange) o-ring where it contacts the housing. I tried a sparing thin film...didnt work so well. Once I put grease on the contact surface of the o-ring it popped in. Plugs and connectors made a noticible difference. The idle got really smooth. Good punch on go-with-throttle-up. i dont get that annoying one-time dip in power about 20 yards from the driveway after cold start. Motive bleeder? Tell me more, I'll be doing the rears in about 4 months. The front suspention refresh (and new wheel bearings went really well). In to Champion Motor Sports tomorrow for re-alignment.

I had my car in for a water pump recently. 126k on the clock. I had done the plugs myself at 60k and since they were due I had them and coil packs done this time. Plugs were clean, no oil in sleeves and looked good (like jackstand loui's). The coil packs looked old and tired, but I had not had any failure to date. Just did them "because" and yeah, they ain't cheap!.

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http://motiveproducts.3dcartstores.com/

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Ironic. Couple months ago I was in the same position. Changing my spark plugs at my 60k service with my local Porsche Indy. A few hair line cracks on the coils but not a single misfire or CEL. Since I didn't want to wait for new coils to come in the mail with my car at the shop, decided to change just the plugs and i'd change the coils and plugs again a little sooner at 75k... 5k miles later, took my car out of town for this past weekend with the family, and I got a misfire that precluding me from driving. It was the coils. Not a huge cost, but a big hassle since I was out of town, and I paid the same labor to do the same job again but this time with coils. The Porsche indy shop has seen several coils go bad in the 996. I think its relatively affordable insurance to change the coils with the plugs at 60k. Pelican parts has them pretty cheap too. The local Porsche shop charged some outrageous prices.

Points to take away from this job: 1. WD40 on the shield and coil bolts saves your ***. Spray it on and leave it for a half hour or so. Go watch football and when you come back, it miraculously loosens those stuck bolts. I've known this trick for years but it still amazes me each time. 2. Good tools are key: I am going to buy better ratcheting wrenches and hex key wrenches 3. Space is bad, but not that bad. I tore up my arms and hands worse on other jobs. For example, the 2nd and 3rd spark plugs on the starboard side of a 82 Capri 5.0. Unless you have the hands of Hulk Hogan, you will do fine. What you do need is decent strength in your upper body. Laying down and reaching up for long periods is very taxing. I am getting up there in years, so it was pretty hard near the end. 4. I used the PVC threaded fitting to get the tubes but it was not gripping some of the tubes. I had to wrap some teflon around it to fatten it up so it would get some bite on the tube. It was also too short to get a wrench on it, so I had to thread on some extra fittings on the outside. (see the steel fittings I threaded onto it) Narrating my pictures attached: Mine had 99K miles on it when I did this job. As you can see, the extensions used to remove the plugs. It had BERU plugs and I dont think they were ever replaced. Decent coat of soot, good color, all the same, no oil or other irregular wear on the electrodes. I replaced with Bosch Supers. I am a compromiser (I admit it freely) and I see no reason to fix it if it aint broke. No engine symptoms, and no CEL, so I didnt bother to pre-purchase coils or rubber extensions. As you can see, I did replace the O rings, and a few spark plug tubes (I did preorder these as they are cheap). The whole reason for this job was to fix the small oil leak on the port cylinder bank. It was leaking onto the exhaust manifold and vaporing off. Very stinky, and toxic too. Seeing the oil and grime was satisfying that what I was doing was fixing a problem as well as performing routine maintenance. This job was performed over Thanksgiving weekend, and it hasn't leaked since then. I live out in Los Angeles and I am too poor to afford a place with a garage, so I had to do this work at my parents retirement home in Kingman, AZ. Then came the road test, and I happily made some runs up and down the I-40. I swear this car performs better than the 5.2 0-60 time it is rated for. It reaches 100mph in the top of 3rd gear! Not a turbo or anything fancy, just plain old Porsche Then my clutch started slipping (yikes!) so I headed back to the bat cave. The knowledge on this forum was invaluable to me. It helped me with the confidence needed to tackle this job. I dont think I brought much new information to this thread, but my goal was to add my experience in case someone is pondering some questions that i had during this job.

Hi guys im new to rennline my car is a 1983 930 and im having an issue deciding which spark plugs to buy. The bosh set at $14 a pice seems overly expensive and im not sure they are the best option ive also been looking at some denso sprak plugs. Any ideas?

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I would check over on the 911 Turbo forum. They will have a lot more experience on what plugs your air-cooled 911 needs...

Hey Jackstand ... I got my 0100 European Bleeder from Amazon for about $50. Easy to use. Put new brake fluid in canister and screw cannister top on and the other end onto the brake reservoir under the hood. Pump the pressure up to 20ppi no more. Then undo the brake nipple and bingo out the old fluid comes and the new gets pumped in via the reservoir. Keep your eye on the cannister and pressure. It may need topping up. Keep doing that untill you see the newer fluid and nip up the nipple for good. There is a sequence to the bleeding of brakes. I think rear passenger, rear driver. Front passenger then front driver. Check on that though.

+1 Bale, Im glad you posted this before I did. Why not change them now? By the Pelican kit and be done with it.

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Hey Louie, Great tip on the "tool" to remove the tubes, thanks! FWIW, Mercedes bought Chrysler, couldn't make it work, sold it to Cerebus who then let it go bankrupt. Fiat then bought Chrysler from the banks. The only thing Chrysler ever bought that was worthwhile was Jeep.

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Not to turn this into an oil like debate - but my Indie who worked at Porsche dealer for 10+ years put NGK in my '02 ...when I asked him why not Beru or Bosch - he just said that he had better experience with NGK plugs. Yeah - check in turbo forum for 930 needs ...

I think your Indy is just blowing smoke and giving his opinion. Any of those TOL plugs should be fine. Most "bad" plugs are damaged by the person installing them. Dropped/cracked, tool/cracked, etc. I should know because Im the dummy that damaged many a plug in my younger years. Now Im extra careful with them.