loose plugs (long)

[JayH]

I know this defies the laws of physics, but all four plugs in my car are loose in the head. I've been driving like this for 18 months since I bought the car. The car runs strong when it runs (it doesn't run in the rain or high moisture). The tail of the spark plug wires can be wiggled in all directions a good inch. The wires are old and I've wanted to replace them along with distributor cap and plugs, but I've been terrified to touch anything fearing the head is stripped or the thread are seized in the head and I'd end up with an even bigger problem. It's my daily driver, so I can't afford to be without it for the long term. A rainy day here and there is already too much. Could the posts of the plugs themselves be cracked somehow? Is this possible? Has anyone heard of such a thing? It doesn't make sense. The distributor looks fine, the cap looks fairly new and no discernable cracks, so I'm assuming the no starting problem when wet is related to this loose plug situation (and old wires, plugs, etc). Any thoughts?

[KFunk]

As I recently found out, it is easily possible for a plug to be broken in the middle where the metal meets the ceramic part. In this case, the threads are still in there tight and the plug can be easily removed. But you can wiggle the ceramic part quite a bit, and spin it freely inside the metal part. The compression will leak thru the middle, and melt your spark plug boot.

In my case, I caught it quick, feared that threads were stripped, but nope. I got new plugs, and molded some RTV silicone to repair my plug boot.

I'm sure the lack of compression in one cylinder took some power from the engine, but it wasn't extremely noticeable.

Anyways, are you sure its the plug thats loose, or is it just the wires? With the combo of stock plugs and wires I got from an import parts shop, the wires felt really loose on the plugs. It's because the stock wires slip over the threads on the back of a plug, not the little nub thing that often comes on plugs.

With my new Accel wires, they use the little nub thing, and its much tighter.

[winstontj]

I know this defies the laws of physics, but all four plugs in my car are loose in the head. I've been driving like this for 18 months since I bought the car. The car runs strong when it runs (it doesn't run in the rain or high moisture). The tail of the spark plug wires can be wiggled in all directions a good inch. The wires are old and I've wanted to replace them along with distributor cap and plugs, but I've been terrified to touch anything fearing the head is stripped or the thread are seized in the head and I'd end up with an even bigger problem. It's my daily driver, so I can't afford to be without it for the long term. A rainy day here and there is already too much. Could the posts of the plugs themselves be cracked somehow? Is this possible? Has anyone heard of such a thing? It doesn't make sense. The distributor looks fine, the cap looks fairly new and no discernable cracks, so I'm assuming the no starting problem when wet is related to this loose plug situation (and old wires, plugs, etc). Any thoughts?

Use a torque wrench on the plugs and you'll never strip out the threads. It may be a pain but it's worth it. Just replace the plugs, wires, cap, rotor, points & condensor while you're at it. If you read the back of the plug box you'll learn that they don't need to be all that tight. As others have mentioned it could be the ceramic, or it could be the wire. Even if you do have a stripped thread you can helicoil it. Chances are they are probably loose and just need to be tightened.

Maybe someone will chime in and state the proper torque per the BMW factory manual.

[jgerry2002]

Don't fear something as simple as a spark plug. Use a good quality deep 6 point socket and a small extension and pull the plugs out. Many spark plug sockets have a piece of foam or rubber inside that will grip the plug when you remove it.

As the other poster said, depending on the design of the spark plug wires the end will be flexable. This is perfectly normal.

As far as replacement plug wires go, Maximillian sells a really high quality set that is worth every penny. I've been through the cheapo and even supposedly "better" quality wire sets from local stores and they are all junk and don't last too long. I've had ends crack, I've had uneven running do to resistance issues, and even melted wire.

[KFunk]

Oh, and the proper torque for a spark plug is between 21 and 25 ft lbs., I forget which. That doesn't seem like much, but it is a lot tighter than I expected. I'm used to just snugging them up firm by hand, but it felt like I needed to go much tighter to get it to the right torque. So yes, I check the specs and use a torque wrench every time I have a plug out.

[02Les]

If you're holding the plug wire and getting the movement there, then it may be the fit of the long plug connector on the plug itself. Mine's been like that for 20 yrs.

[JayH]

I suppose it could be in the plug connector. The wires look original (it’s a 76 ’02), but I don’t know about the plugs, they may have been changed and “mismatched”. A fitting issue would be a simple fix. Let’s hope. Everyone’s suggestions have given me the courage to dig into things this weekend. Thanks guys.

[Paul7002]

New wires (Call Max - great wires) and plugs and I bet you're fine. But cap and rotor probably need changing too.

don't be afraid!

[Timmer]

I can tell you guys it happened to me, about 4 years ago, in my '69 2000, shortly after the engine rebuild. I heard a light ticking noise which eventually got louder and then kind of a "bang". I thought maybe some part of the exhaust had gave out but then knew I was running on 3 cylinders. I pulled over, opened the hood and one of the spark plug wires was just dangling. I took a small mirror and then saw there was no spark plug for that cylinder. I had a spare set of Bosch W-7DC's in the glove box, threaded/tightened it down and all was good but that was a first for me., replaced the other 3 shortly thereafter. I back tracked and found the prior spark plug a few blocks away, pretty strange. I guess that one spark plug may have been just a bit over hand tightened for some reason.

Tim

'69 2000

[JayH]

Same thing happened to me a few years ago with a Volvo. One of the plugs was slightly loose, although nowhere as loose as the ones on my '02. That was a serious pop. The threads in the head were stripped. What a pain. It's why I've been overly cautious about messing around with them here. It runs beautifully, when it runs, so I haven't wanted to mess with it. Unfortunately, things are gettin' old and need to be replaced.

[BillWilliams]

Drop a drop or two of light machine oil on the cotton/wool pad in the center of the distributor under the rotor button.

[Timmer]

Yes, I do this prior to the 2000's first drive in the spring, drop of oil on the felt pad. Also, a dab of copaslip ( non seize paste ) on the spark plug threads when putting in new spark plugs. I'll tell you though, I actually had a bad feeling when I heard the pop /bang noise prior to the spark plug popping out. The engine was rebuilt a few months prior to that incident and I thought something in the motor had gone had. The exhaust system was also renewed at the time of the engine rebuild so I kind of knew it couldn't have been the exhaust. I'm guessing Mark may have gotten sidetracked when putting in the plugs after the motor was done, forgetting to tighten down that one spark plug. Last summer, after changing the oil/filter on my Corolla, I forgot to firmly tighten the cap on the valve cover ( I barely twisted it back on ) as I checked the oil level a couple more times; shortly after, after a bit of driving, I smell oil and then see the cap bouncing down the road. I lost about a quart of oil, all over the engine bay, big mess. I couldn't find the cap so I had to buy a replacement oil filler cap and luckily I was right by an auto parts store.

Tim

'69 2000