Spark plugs unfit for purpose?

Your assumption is wrong. Spark plugs should be changed at least every year or 10000 miles - whichever comes first. As they cost only a few pounds, I can't think why you should quibble.

Hehe, fair enough. Another entry of mine into the "Stupidest Usenet Post 2005" compo ;)

Thats the last time I rely on advice from my wife's Grandad when it comes to cars! ;)

Cheers, GazChap.

In message , Raymond Berry writes

It may or may not be the case with the Micra but in general, plugs last a lot longer than 10,000 miles these days. For example, the plugs on Ford engines are changed at 40,000 miles.

cant say for a Micra, but my Mitsu plugs were guarenteed for 50K miles and that was also the reccomened changing time in the service Schedule!! imho id suggest the garage used poor Quality plugs (all else being well)

Good Luck tho!!

Lost

I would be very interested to see what condition they were in when pulled. Most Haynes manuals used to give colour piccies showing you what to look for on good and bad plugs. Adjust gap wire brush off,, cracked insulators etc. I would suspect the leads rather than the plugs at first as they can carck with age and heat and are often overlooked..

Micras have a tendency to overfuel on cold starts (effectively that's what flooding is - someone with technical knowledge will be along to provide proper details in a moment!) and are the sort of cars that tend to be used mainly on short journeys, neither of which are likely to prolong the life of the spark plugs. As other posters have suggested, it isn't really worth your while pursuing this with the garage - a set of new plugs will probably be about a tenner (completely random guess, but they're not going to be that much, even from Halfrauds) and the car needs a good run. Also, tempting though it is, avoid using the accelerator when cold starting.

Yes, but they use Platinum plugs for that mileage.

Yes it is correct. However, it'll depend on what plugs they put in. Japanese type engines are pretty well renowned for having a preference for NGK plugs, anything else is very likely to fail before the scheduled change time.

The Micra was due for plug changes every 18,000 miles, although they could easily do 24,000 miles now. Even though you haven't done the mileage as specified, it's almost certain that they will only have a 1 year warranty.

The message from "Raymond Berry" contains these words:

Cor - spot the sweeping generalisation!

Thought they were simply hot run plugs similar to those in muscle engines of the 60's ?

No, they're platinum. Most other cars can run them for 60,000 miles, but Ford still run the wasted spark system, so they don't last as long.

Bollocks. Modern plugs do 40,000 miles.

The above is exactly right. I just changed the plugs in a 1.0 Micra after 30,000 miles - it didn't really need to be done. Changing the plugs is easy but here's a few tips (plugs cost me less that£20 btw from a Nissan dealer - suggest you get 'em there, they are "guaranteed" for type/qual.) On the Micra the plugs are recessed several inches in the cylinder head. You WILL need a "special" plug spanner to get them out/replace (not only the length - but needs a rubber insert to safely remove/replace the plug out without dropping it). I got one from a tame excellent car parts bloke - Halfs may have them. A plug that's been working ok will have a light brown colour. Get a workshop manual - Haynes is ok for this

- has pics of the plugs and lots of useful info. The plugs I got from the dealer were already gapped by the correct amount (quiet a large gap - I think it was

As to flooding - yes my Micra did that a few weeks ago. There is a fix which involves pulling the fuel pump fuse but unless you know what you're doing I suggest not trying that, There is a 2nd way, which is... Press accelerator to the floor and keep it there. Gear in neutral (:-) ) crank the engine a few times

- several engine revs with some resting time to let the battery recover and the starter motor cool off :-) If this fails (and if flooding is the problem) repeat with fuel pump fuse removed. Replace fuse and try restart. HTH

The wife managed to find her Haynes manual shortly after I posted and found that they are supposed to last 18,000 miles as you say.

I think we will just let it slide and get new ones though, as you've all said its not worth fighting over for a few quid.

Still irks me a bit though, if this garage is flogging substandard parts. I suppose its difficult to prove though.

Cheers for the help all!

GazChap.

I very much doubt they were/are substandard. The life of a plug depends very much on the tune of an engine, and how it's used. Mike.

What is wasted spark?/

sounds very star wars?

:-)

A 4 stroke engine fires each cylinder once every 2 revolutions. Wasted spark means that each plug fires once every revolution. i.e. at the top of the exhaust stroke as well as at the top of the compression stroke. As the exhaust gases can't burn for a second time, the spark is 'wasted'.

The garage isn't flogging substandard parts. The problem was the over fuelling, the breakdown service then flogged you plugs as an extra. There is no way they were worn down in 11K miles. Demand your money back

Steve

I bought my BMW at 50k miles and somewhere around 100k I decided to change the plugs. The ones I took out were still within spec. At 150k milesish I had need to remove the intake manifold and throguh the inlets I could see that the valve stems and back fo the heads were clean as a whistle. Modern engines really have come on with the advent of computer controlled FI.