Have a 2005 Mini S - just hit 33K miles. Was driving along at about 65 went to accelerate and heard a loud 'pop' noise. Kept driving for a few minutes and pulled over to see that the spark plug on far left side (still attached to cable) was sitting on the engine. Drove it to my office (5 minutes further), let engine cool down and attempted to get plug back in but it will not turn. As a test I took one of the other plugs out and attempted to put it in the hole on far left but it doesn't latch onto anything. I'm guessing the hole is stripped somehow...? I installed NGK Titanium plugs about a year /10K miles ago, replaced the plug cables about 5K miles ago and did the coil pack about 3K miles ago. The plugs were tightened down to factory specs as outlined online when I did them.

What is the guideline for driving the car (or not). Ideally I'd like to get it back home (45 miles) so I can look at it there. Moreover I'd like to get it home so if I do end up taking it to the dealer I can take off all of the aftermarket stuff mentioned above and put the stock items back in. Ultimately I can have it towed but with AAA but if I can drive it then that is fine too. The car just dropped out of factory warranty on October 1st so that stinks.

Any advise / recommendations would be appreciated - thanks.

 

It does not seem like it is worth taking the car to the dealer because you installed the plugs and any associated issues will not be covered by the warranty. Thus leave your aftermarket parts on the car and take it to a good shop if you do not want to do the work.

If you have basic AAA they will only cover a 6 or so mile tow. If you have premium AAA they will cover 100 mile tow. I would suggest a tow if covered by AAA.

If you are going to take it to a shop to investigate/repair maybe you can find one close to where your car is located so you do not have to drive far on 3 cylinders. I have not done it in a Mini but I suspect driving on 3 cylinders will cause OBD codes and put the car in limp home mode.

It is likely that just the top couple threads are damaged and they can be easily cleaned up with a thread tap.

 

I'm sorry to hear of your problem. Plugs blowing out of the head seems to be a not uncommon problem. I know 2 people locally who have had that same thing happen to them. Also Chad at Detroit Tuned has seen this issue a time or two.

Most likely as the plug was loose it wobbled around & ate the treads in the head. The fix is to put a hela coil in the bad spark plug hole. It is possible to do that with the head in place. You need to find a competent mechanic/machinist with experience to handle the job.

Now a word to all. Since having this happen is such a pain in the ****, check the plug torque. I do it when I change the oil. The engine needs to be cold & torque to 25 lb ft.

 

DO NOT DRIVE THE MINI on 3 plugs!

It will cause more damage. If you could post pics of the plug that would help us see what may have happen. It may be a simple http://www.helicoil.in/ fix but make sure it's done right if not will will happen again.

I'd bet there is a NAM Member in the area that could help you with this project.

 

I 2nd the "don't drive it" opinion.

The injector will still operate, and gasoline will be free to leave the cylinder and enter the motor compartment.

Serious safety issue.

 

http://www.timesert.com/html/sparkplug.html

These have been used on other Mini's.

https://www.northamericanmotoring.co...ght=Spark+Plug

 

Heck no don't drive your MINI until it is fixed. If you want to drive on 3 cly get a Geo Metro.

 

haha.. thanks all. I ended up having it towed (well worth the AAA gold membership for the 100 mile tow!) and only had to drive it a max of 3 minutes to reposition it for the tow truck and drive it in the garage at home. I have the spark plug and will post pics. The thread on the plug seems fine compared to the one I took out next to it (to see if it was a plug and not the thread itself). Now that I have it home I'll take pics of the plug and try to get a pic of the inside of the hole to see what is going on. Thanks so much for the replys. Looking online it seems like a (as another member mentioned) common problem which is scary in a way. Thanks again for everyones replies and will post pics when I have them.

 

Also always be sure that the engine is completely cold whenever removing or installing spark plugs. Alloy is much softer when warm/hot and damage to the threads in the head is much more likely.

 

Interesting. If the spark plugs need to be torqued on a cold engine, how do the dealers do it? Usually you drop off your car in the morning and it takes HOURS to cool off back to 'cold engine' levels.

 

Use the factory plugs.

I check these kinds of threads specifically to see what plugs were being used...9 times out of 10 it's a aftermarket plug.

 

I agree, but I can see no real reason an aftermarket plug is any different in regards to the plug staying in. Stock plugs also come out. If one does a precautionary re-torque at oil changes this will not be an issue.

 

It's also important to apply anti-seize compund to the spark-plug threads before installing in the head. This provides a little lubrication for torquing to spec and helps minimize any damage to threads (both when torquing and when removing).

Always install using just your fingers to turn the socket extension so you can feel that you're not cross-threading. If you feel any resistance, unscrew and try again until you're sure it's threading properly. Only after they're all finger tight should you torque them down to spec. Since the thread pitch is so small/fine, it's easy to cross thread the plugs if you're not careful.

 

I don't understand myself why the aftermarket ones are more prone to blowing out.
This is true...but I haven't seen as many cases(maybe 1 or 2) with the stock ones compared to the aftermarket ones.
This would definitely keep this from happening.

I've had my plugs in for a while, and they are definitely due for a change, but I haven't had any issues at all.

 

so the plug looks fine and the issue appears to be stripped threads in the hole on the block. this being said I'm leaning toward trying the HELICOIL myself before looking at other options (#1 being to take the plunge and go to Mini Madness Stage 4) but need to know what model / part number HeliCoil Plug system I need to purchase? Thanks so much for everyones help.

 

just ordered backtap and helicoil kit for delivery tomorrow. we'll see what happens

 

just wanted to say thanks to everyone for answering my questions through this! i ended up receiving the backtap and the helicoil kit and attempted both today. The backtap didn't work because the threads were too stripped (or maybe I didn't use it right..!). So, I ended up using the Helicoil method and after a few hours and a few trips to the store it appears to be set and working. I was able to get the plug in, put some locktite on it and tightened it to about 22ft lbs. Started it up and all seemed fine.. still have a 'check engine' light but I'm guessing that the car will take some driving to get used to having a 4th spark plug again. So again, thanks for all the advice and comments! Jeremy

 

Loctite on the plug??
Please say it's not Red Loctite.

Jim

 

Not only that, the loctite may also isolate the plug from the head, the plug relies on the thread contact for a ground path as well as for heat dissipation. Additional resistance will cause a weak spark on that plug as well as the companion plug since the mini uses one coil to fire two plugs at the same time!

I hope this works out for you.

 

Good luck with your repair, but let me tell you that I acquired my current 2005 MCS (2 years ago) because the #1 cylinder spark plug blew out stripping the threads. I bought the MINI and took it a local MINI mechanic and he put a helicoil in it. Although it was a fast and easy fix, it's not something I'd recommend. As this helicoil eventually led to an entire engine rebuild for me. With the engine out and at the machine shop, they noticed some leaks and they weren't surprised why my engine was with them. Just a hint. A total lower block rebuild, along with a new clutch since the engine was out, and changing my LSD was close to $5,000.

So consider carefully if the cheap helicoil is the best way to fix the problem for the long run. The best way to fix it is to pull the head off, and put the helicoil from above and below the head, but that involves additional labor which I didn't do at the time.

I was told as long as you don't plan to track the car, the top installed helicoil was fine, I never thought it would lead to destroyed rings.

Good luck.

I'm happy with my new more powerful engine.

Richard

 

I have never heard of a case where stock plugs installed at the factory blew out.

Very few cases where stock plugs installed buy owner blew out.

98% of cases where I've heard of a blowout was after market plugs installed by the owner.

 

Anecdotally I would say that the vast majority of user installed plugs are aftermarket and that would account for why you don't see a lot of OEM plugs getting ejected. And that would be because most OEM plugs have never been touched since they were installed at the factory where they were installed to the correct torque on a cold head.

I'm thinking that ejected plugs come from installing them on warm or hot engines. My Denso's have been in for 50,000 miles now and I have checked them every 5000 when I change the oil. Never have they been loose at all. It is hard for me to conceive what in an aftermarket plug would cause it to come loose other than improper installation.

Rich

 

Ditto!!

Jim

 

Just out of curiosity, where do you get 25lbs/ft? I've see 21 and 22lbs/ft here on NAM and the Bentley manual states 20lbs/ft.

 

That is what a very respected MINI guru who I trust told me. 25 lb ft works for me. As they say your mileage may vary.