Advise I read on spark plug changes doesn't sound

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cadfaeltex

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...right. On my 2008 MINI Cooper S convertible (R52 with supercharger), the book says change the plugs every 100k. I'm currently just shy of 70k but thought about changing since I have them. Went to a mini forum to check out opinions on the matter. Was surprised to find that many were suggesting 30k changes on not only the plugs but the wires and coil as well. These are iridium plugs - not copper. The service manual suggest changing the wires only if they show signs of wear and nothing about the coil.

So what is the opinion here on the matter?
 
Originally Posted By: cadfaeltex
...right. On my 2008 MINI Cooper S convertible (R52 with supercharger), the book says change the plugs every 100k. I'm currently just shy of 70k but thought about changing since I have them. Went to a mini forum to check out opinions on the matter. Was surprised to find that many were suggesting 30k changes on not only the plugs but the wires and coil as well. These are iridium plugs - not copper. The service manual suggest changing the wires only if they show signs of wear and nothing about the coil.

So what is the opinion here on the matter?


Don't listen to those part swapping morons.
 
My advice is to pull one of the plugs out and check the gap. You probably don't need new plugs, but they might need re-gapped.
 
Hey cad, I too am a Mini Cooper owner (2010 Base Hatchback). I would follow the recommendation of Merkava at the very least (but check all four plugs), and I would follow the advice of the Mini forum users over the manual or other less helpful users. The Mini owners don't recommend making those changes because they like wasting money and parts, they recommend it because they have found, usually the hard way, that the parts wear out that quickly. When I bought my car with 51k miles on it, I removed the spark plugs to have a look at them. They were HEAVILY worn, the gap was nearly double the spec and the ground electrodes were visibly eroding. When I put fresh plugs in it instantly cured low engine speed stalling and hesitation that I had been experiencing.
 
The factory owner's manual was written by people that designed the car and the engine and they might be your best source for information that you can depend on for your Mini.

Those iridium plugs are up to the job. The plugs that came out of my 4Runner V8 at 100K looked hardly worn at all. I was tempted to leave them but decided that following the owner's manual was the best course of action.
 
Originally Posted By: OneEyeJack
The factory owner's manual was written by people that designed the car and the engine and they might be your best source for information that you can depend on for your Mini.


The problem with that approach is you never get an addendum to the owners manual when issues arise and are corrected. A lot can change since 2008
I have one FSM here with 4 addendum's.
 
I'm guessing it's not based upon its age, but does anybody know if this is a DI engine? I did some internet poking and the answer was not obvious to me.
If it is, LSPI has been an issue in some DIT engines and I'd imagine supercharged ones would be in the same boat. One of the things the dealers were supposed to check for in the recent predetonation recall for late model FXTs and WRXs was spark plug damage...I was told my plugs looked "OK" at 40k, but they offered to replace them for the part cost and I agreed. 20k ahead of schedule, but I did get the old plugs back and they looked well used (but not heavily eroded like some examples from recalled FXTs I saw online).
 
cadfaeltex, I can speak to this with some degree of experience. My dad has an 06 cooper S (R53, same engine as yours) and is on its 3rd set of spark plugs at just under 70,000 miles. The first change was when he had the supercharger pulley changed out.

The mini dealer here has basically said, that even in stock form, 30,000 miles would be optimal for changing the plugs. The stock plugs don't need to be (cant be) gapped as they are the 4 prong jobbers. Some people say "GO BY THE MANUAL" however that same BMW manual is the one that lists 15,000 miles oil changes, "lifetime" transmission fluid, and does not take into account that it is a sports car and not an ecobox.

Also, you mentioned the Coil. his Coil was just changed out at 70,000 miles, as it was causing engine misfires and limp mode occurrences. So those people you see recomending it may be doing it before its a problem, but it certain does look like it could be a problem. Now, this R53 has been pushed quite a bit (not babied), so I would say you run your car as it was meant to be, go ahead and change the plugs!

Here is a shot of the plugs from the most recent change. I cant say for sure the mileage, maybe less than 30,000. Keep in mind this car has a Pulley upgrade (15%) so it is pushing a bit more power, but the first plug change around 30,000 the car was completely stock.

tjmpmhk.jpg
 
Originally Posted By: Merkava_4
My advice is to pull one of the plugs out and check the gap. You probably don't need new plugs, but they might need re-gapped.


If the gap on a platinum or iridium plug needs readjusted the coating is gone and the plug will wear much quicker. There isn't much there and that is why they say not to even check the gap on those plugs. It can be damaged real easy.

I have read that in some applications not originally designed for platinum or iridium plugs that going to them can cause detonation problems. Just some Info I have read over the years.
 
Maybe the Mini plugs should be changed more often considering the car is a 4-wheeled problem waiting to fail. A co-worker had a supercharged one that was about a month out of warranty when the engine blew up. The vacuum pump failed and ate the cam chain which ate the engine. The car had been faithfully service at the dealer and this vacuum pump problem was a known defect. The warranty claim was denied and the repair was about $7.5K. The owner sold the car the week he received it back and you can bet he'll never buy a BMW product again, ever.

You can watch his face turn red by just asking him how he liked his Mini.
 
Originally Posted By: Virtus_Probi
I'm guessing it's not based upon its age, but does anybody know if this is a DI engine? I did some internet poking and the answer was not obvious to me.
If it is, LSPI has been an issue in some DIT engines and I'd imagine supercharged ones would be in the same boat. One of the things the dealers were supposed to check for in the recent predetonation recall for late model FXTs and WRXs was spark plug damage...I was told my plugs looked "OK" at 40k, but they offered to replace them for the part cost and I agreed. 20k ahead of schedule, but I did get the old plugs back and they looked well used (but not heavily eroded like some examples from recalled FXTs I saw online).


It is not a DI engine. It is the tritec engine co developed with Chrysler.
 
Just because a manual tells you to replace spark plugs at a certain interval doesn't actually mean the plugs will last that whole interval.

My 2003 Saturn ION specified 100,000 mile spark plug changes, but the engine was running rough at 60,000 miles. A new set of spark plugs fixed the problem.

What surprises me is that a company specifies replacing ignition coils at certain intervals. I have always been told to leave the ignition coils alone until they fail.

Sometimes a company may recommend replacing the ignition coil boots, but not the actual coils. That makes sense. That would be like replacing your spark plug wires and spark plugs at the same time if you had a distributor type ignition.
 
Manuals indeed can be wrong. Toyota says that my Type IV ATF is lifetime fill not needing any maintenance for 100k miles. Every UOA shows that to be very wrong. My manual for my Monte Carlo says 7,500 mile oil changes. That was with notoriously bad 1980's conventional oil on a carbed engine.
 
Follow what the common consensus on the owner forums said, they probably already know some design problems that the manufacturers didn't want to admit or didn't find out until it is very late, too late.

If I remember right some of those fine wire iridium doesn't last as long as the thicker wire iridium we commonly use, and cannot be expected to last "forever".
 
Originally Posted By: Merkava_4
My advice is to pull one of the plugs out and check the gap. You probably don't need new plugs, but they might need re-gapped.
these arent copper plugs
 
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