removing mufflers to do spark plugs

Has anyone had to remove the muffler to do the spark plugs? If you would you let me know how to attack the job and size of wrench used if possible. I am trying to loosen the first bolts and came to a dead halt as they don't move even after spraying them. Is it better to leave it overnight to soak into the bolts? I thought of heating them but don't have a torch until tomorrow. Any suggestion and details of muffler removal would be well appreciated. These are the two bolts http://www.ex-lancs.com/web/BOLTS.jpg

You do not have to remove the mufflers to change the spark plugs.

I do. I don't like struggling, bashing my hands about and can't see where I am working. If you have done yours without removing them, if so tell me how please. Its got to be all by feel and I am changing the sleeves as well.

I changed all spark plug tubes and spark plugs without removing the mufflers and I did not have any trouble doing so. I would assume that having the mufflers off the vehicle could or would make it easier, but then it comes down to the difficulties you may encounter by removing the mufflers (rusted/hard to remove bolts as it appears you may have). I had no problem. I jacked up one side of the vehicle and did that side and then moved to the other side. The tubes came out very easy using the boat transom plug (and the o-rings on mine were very distorted and leaking). I found it to be a pretty easy job. However, you need to do whatever you are most comfortable with and if removing the mufflers works better for you, then that is what you should do..

I will remove the first one on each side now in the hope that I can work in there without seeing the next two on either side. I have the full back end on stands and using a crawler. If I can loosen the bolts tomorrow after a long soaking then I will remove them. Thanks for your advice. I hope I can get to the second bolt on the heat shield first though.

While it probably can be done with out removing the mufflers, it will be easier if you can remove them as it gives you better visibility. You will still have the mounting bracket in front of the last cylinder on each side. I pulled both of mine off about a month ago so I could replace the spark plug tubes. I didn't have any problems with rusted bolts (a southern car) - 3 bolts holding the muffler to the hanger and 2 bolts for the muffler pipe sleeve clamps.

Agree with pmkazz. I've done it w/o removing the mufflers on a '99 and a '03 without problems. The '99 was much easier somehow. Those bolts you're trying to remove are the right ones for muffler removal. Best is to spray them with PBblaster or Kroil but still you may struggle with other bolts. For the coils, you definitely want a 5mm hex bit with a mini ratchet like these http://wetlands.simplyaquatics.com/d/286-9/IMG_4938.jpg

Hurdi, I removed the mufflers and the muffler mounting bracket so I can see what I'm dealing with, especially when I've never done this job before, perhaps I could do so "blind" the second time around, but why make your life more difficult? Yes it's always best to soak the rusted fasteners overnight or even for days to allow the penetrating oil to do its job. Anyway, besides the two bolts you show in the pix which connect the catalytic outlet to the muffler inlet, there are two long bolts attaching each muffler to the muffler bracket, there are also 3 bolts holding each bracket to the engine block. If you are having difficulty with the muffler clamp bolts, then you likely will have problem with the two long bolts, as they are installed with the nuts at the bottom side, exposing them to the usual salt spray etc., so soak them with penetrant spray like PB Blaster etc., I also used pneumatic impact wrench to help loosen the various fasteners for the muffler, a trick is to install these two long bolts upside down so the nuts are at the top when putting everything back together, so you don't have to remove the bracket to get the mufflers out in the future. Actually on second thought, you don't have to take these two long bolts out if you just take off the 3 bolts holding the muffler brackets to the engine block so each muffler/bracket comes off as an assembly, but I decided to loosen everything so I can coat the threads of the fasteners with anti-seize to prevent further rusting of the fasteners.

PMkass, I am also in the middle of doing the plugs but stopped on the last 2 hardest to reach. Can you offer some insight on your process for removing the last two w/o the mufflers? Thx

Hurdi, the job is much easier if you remove the mufflers, especially for old timers like us. There must be 100 DIY about every aspect of the plug change job. Its also a good idea the keep the muffler bolts/nuts rust free for easy removal. I have removed mine so many times, it only takes about 15 minutes, if that. It helps to have a swivel, air ratchet, etc. If I were closer, I would help you or at least give moral support. I admire you and your ability to put up with the crap you get here. I only pray I will be able to do these DIY's if and when I reach your age.

Hey Ken Thanks mate. I take everything with a pinch of salt from other posters. I deserve everything I get as I give more than they shoot at me. Every guy who has a 996 has got to be a decent chap. We are a breed apart. So anyway I have snapped one of the bolts in half and that's ok. I have to change them anyway. So I am gonna do the same with the rest.

Leave these two alone. "Anyway, besides the two bolts you show in the pix which connect the catalytic outlet to the muffler inlet, there are two long bolts attaching each muffler to the muffler bracket , there are also 3 bolts holding each bracket to the engine block".

FPB111 Thanks for the info. I didn't have to undo the two long bolts. Just the three small ones on the bracket and the muffler came away after I snapped the two original bolts on the tail pipes to the muffler. I had already replaced two plugs and sleeves which I could get at before the muffler came off on the passenger side. Now I can see the 3rd coil but the top little screw holding it on looks pretty hard to get at. But I have done enough for one day and gonna watch Man United on tele. I am retired and have lots of time on my hands so there is no rush to finish the job. My wife is away in Florida at a conference till Wednesday. Screwing about with the car gives me lots of things to do instead of screwing that woman across the road hahaha. Yeh chance would be a fine thing lol. I believe that the hard part is the passenger side. I love a challenge. "OK 996 bring it on lets see what you got haha."

Wausau 911, Sorry I do not really have any advice other than just doing it and have a good tool set. Mine is a 1999 and it just like Ahsai said, I didn't have any problems. Sorry I cannot be more specific, it just seemed to work ok for me without removing the mufflers.

Pmkazz = California Wausau911 = Wisconsin I love working on them Californian cars. Mine was from Georgia all it's life and just as pleasurable.

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+1 on "PB Blaster". Works better at loosening those rusty bolts than WD-40, especially if you leave it overnight. I think they have it at Home Depot.

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Right and all I remember is the most difficult two DO look impossible until you try to wiggle them out.

Careful with the nuts on the 3 studs for the catalytic converter to exhaust manifold. Even after soaking for days with Kroil, a simple twsit with the socket snapped the stud soff, then I had to grind off the remaining stud, and drill through in order to install a bolt. I replaced all the nuts and bolts with stainless steel. Eff the rust. I took my mufflers off in order to perform the Fister D mod, then installed the long bolt with nut on top so it will always be easy to remove the mufflers anytime. It is SO much easier to do with mufflers removed, that the time it takes to get them off is less than the additional time required to work with them still on. As long as you don't snap any studs. Even SS bolts are cheap & easy.

So I did the job as preventative Maintenance. I bought plugs and sleeves about a year ago. The car was running just fine anyway but decided to do them. I had no idea when the plugs and sleeves were changed. I did find out on the very first coil passenger side that another screw had been used in that part so obviously these were not the same plugs which left the factory in Stuttgart. Nothing at all appeared wrong with any of thwe old plags or sleeves as I changed them. Here is a photo of them. This was probably the hardest DIY I have had to do on the car but I enjoyed every minute of doing it. I jacked the engine as high as the jack would go and used two stands. The back of the car was about two foot off the floor. Removed back wheels and mufflers. Then using a crawler slid around under the car to complete the job. The marine plug on the sleeves worked for me treat. One big glitch and all my fault I tried for like Everrrrrrrrr to put a coil back into where I had put the new sleeve and plug . Oh for two hours before I realize that the plug spanner had been left on the new plug. haha. Apart from a slight bump on the forehead I am unscathed. Aching, muscle weary and 6 pounds lighter than when I started the job. Loved it and the car is purring away good. I have yet to put the rear wheels back on and take it on the road. http://www.ex-lancs.com/web/plugs.jpg I have since ran the car and the response from the accelerator is awesome in comparison. Its a smoother driving experience all round. When I saw how good the plugs and sleeves seemed as I was removing them I didn't imagine that the new plugs made would make THAT much difference but they have. Reading other pages I am not the first person to drop off the plug tool inside the sleeve haha.

Job well done. I hope you got either OEM plugs or another set of long lasting plugs. I hope you also reversed the muffler bolts. It can be a pain to do that but luckily you don't have to do them that often, unless you subscribed to KK school...

Jumping on this useful thread, I am also trying to remove my mufflers (not to do the plugs, but to replace the mufflers). *all* my bolts are rusty beyond belief - I don't think the mufflers have aver been removed in 11 years. Must of the bolts were rusted down to thin "nails" or rusted completely through. You can see that I managed to remove the long silencer mount bolt - snapped the nut off then pushed the bolt up (thank fully it moved) then used a small hacksaw to chop the year off. Replaced with a new bolt the other way round (nut at top). The short mount bolt nut is toast. I can pick away at it to remove it but then I can't push the bolt far enough through to remove it and I can't get to it with a hacksaw - if I remove the rear bumper can I get to it ? I see picture on the net but I think I also have to remove the heat shield material ? any advice on how to chop the short bolt head off The three bracket nuts are equally toast so they are definitely not coming off until I get the muffler off. I've already removed and replaced the muffler to cat clamp bolts so it's just the short one left... oh and here's the car only picked it up last weekend 2002 C4 Tip S Arctic silver/Red leather Lee

Congrats Hurdi! Impressive and I like your "no need to hurry" attitude.

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I am retired and will be 72 years of age tomorrow. My good wife was away on a conference in Florida until Wednesday so I had lots of room in the garage to work and slide around on the crawler. The hardest part for me was getting on and off the crawler. My body is not so supple these days. My body ached. I fathomed it all out. Where there is a will there is a way. It runs absolutely great. I thought it did before but since doing the plugs and sleeves. The difference is amazing. It's DIY like that I wish I had a garage lift. I enjoyed doing ti anyway. DIY brings driver and car closer together and we know the job was done well.

Well then... Happy Birthday!!!!

Thanks Silo.

Happy Birthday as well Hurdi! Wondering if you got any kids(or grandkids) wanting to take your ride for a spin?

Well done and Happy Birthday!

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Thanks again you guys. Well I am originally from the UK. Married a U S soldier girl (16 years my younger) who was posted in the UK. Got 3 kids to my first wife all in England. They have 4 kids between them making me a granddad of 4. The ones that come over to see me are too young to drive. But their dad is not so I let him drive my youngest daughter and 2 kids around and trust that they get back in one piece haha. I fly to see them all two times every year and they come to see us one time. It's so expensive travelling these days. (No kids to the soldier girl) She is a career girl. She bought me the 996 as a surprise early 70th birthday present. I was 22 years of age when the 911 came out in 1963. Always admired and wanted one but could never afford one. Thank god for the scare mongers hahahaha

I went to attack this job yesterday and, while trying to remove the mufflers, found that the long bolts were inserted from the top (nuts on bottom). From pictures here it appears that's backwards. So, there was no clearance to remove them. I really wanted to be able to see what I was doing since this is first plug R&R for me on this car. Guidance on remove he muffs in this situation? Thanks Todd 99 coupe

CrossT...the long bolts are inserted from the top from the factory, but you should still be able to get a box wrench on the top and a socket on the bottom...that's what you're going to have to do to put them back on anyway...the other option is to remove the three bolts that hold the muffler to the bracket and take it out that way...then reverse the long bolts once you are reinstalling...

You have to remove the three bolts which holds the intermediate muffler bracket to another bracket on the engine block, you will then remove the muffler AND the intermediate bracket together, remove the two long bolts, and reinstall them "upside down" from below so it will be much easier NEXT time.

Ok, I gave up too soon and need to get under there again I see. I have a four plug misfire per my code reader. My plugs are a minimum of 25k in age. I've avoided this since the car has run perfectly until now. Thanks Todd 99 coupe

To get the cans off it is just 3 nuts and loosen the 2 bolts by the cats. The bracket that is mounted to the motor stays as is. Like said above once the cans are out you can flip the bolts on the bracket the cans are mounted to and next time just unbolt those to remove the mufflers.

I had loosened the sleeves and the two nuts on the long bolts. There is another (third) nut? I'm going to head over to where the car is stored and check it out now. Thanks Todd 99 coupe

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No, the 3 horizontally mounted bolts/nuts are used to attach the intermediate bracket to another bracket mounted on the engine block. There are only two vertically mounted long bolts securing the muffler to the intermediate bracket.

See post 13 of this thread https://rennlist.com/forums/996-foru...placement.html , the 3 horizontal bolts/nuts attach items 23 and 17 together, these are the 3 I was referring to.

All in an ideal world folks, but these cars are so reliable many engines might not have been out ever. This is what I found and had to do. It's no complex but took time and all my weird tools to crack it. http://911uk.com/viewtopic.php?p=904728#904728 Lee

Success. Thanks for clarifying the correct nuts to remove. Car runs great now! No misfire, no CEL. Now on to the leaky water pump. Thanks Todd 99 coupe

Water pump will be more painful in comparison. Read up on the water pump replacement threads, you WILL need 1/4" drive universal, 1/4" drive 10mm deep socket, and you may also want to get the UVIEW bleed tool, even though you are likely only going to use it once.

Thanks. This will be my second water pump. The first was aftermarket with metal impeller. I won't do that again and have ordered an OEM unit. . . The cheap aftermarket unit lasted three years. Not long enough Todd 99 coupe

My misfire CEL came back already. I noticed when I removed the plugs that one was fouled. The other 5 were normal looking. Makes me think the coil is bad on that cylinder. Probably a good assumption? Thanks Todd 99 coupe

Todd, what code are you getting?

I ordered a coil already since they only $40. It throws OBD code P0300 and one more 300 for the specific cylinder. It is the driver side forward most cylinder that was fouled not that it is important which. The car is fine after 30 seconds when it starts to warms just a little Edit - that code read is just by my cheap scanner Thx Todd 99 coupe

Where did you find a coil pack for $40. That's a great price.

While I am a loyal Pelican guy, especially due to their excellent 911 forum. I split my buys with them and AutohausAZ depending on urgency. This being urgent. Autohaus is in Phoenix and I am in Tucson, so for me they are very fast. I now am getting a P1316 code [cyl 4?] and the car runs quite poorly. Which is cylinder 4? I am hoping the coil pack cures this. thanks Todd 99 coupe

stolen from another thread...

I have found Pelican to be quite fast. They even have a cheap overnight option on most parts.

I have a cylinder 3 issue where there is a persistent misfire; backed up by OBD codes. I have replaced the plugs and the coil and the problem persists. The #3 plug keeps fouling. I have noticed that there is a lot of cloudy exhaust coming from the right side - i.e., for the left head. All of these issues seem to clear up after the car warms. What do you think I should look into? thanks todd 99 coupe

Could be fouled by bad rings or a failed valve guide. Can be verified by a leak down test at a garage.

Thanks. I will take it a local guy this Friday Todd 99 coupe