Jackstand Louie

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!

Ubermensch

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

Barn996

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.

soverystout

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.

relinuca

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

Revn29k00

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

Jackstand Louie

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.

LordVicious

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.

Macster

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.

Jackstand Louie

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)

Macster

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.

wyovino

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

Jackstand Louie

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.

wyovino

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.

Macster

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.