Author Topic: Spark plugs. (Read 3022 times)

Jocko · « **on:** January 16, 2017, 10:45:43 AM »

I will be coming up for my first service shortly and was wondering if it would be a good ideal to fit Iridium spark plugs in the rear position so that , for the next few services at least, I wouldn't have to change them. For an OAP, it is a big chunk of my motoring budget to fit 8 of them, but I could run to 4. Will this have a detrimental effect on the running if I mix and match?

guest1372 · « **Reply #1 on:** January 16, 2017, 11:23:02 AM »

At over 100k miles I've not had an issue with the service life of standard plugs so would recommend standard all round, but although maintaining an identical set of plugs sounds better I believe there is no reason that mixing them would be detrimental. Plugs performing properly should have the same end result.

Some interesting discussion here: http://www.sparkplugs.co.uk/iridium-spark-plugs
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TG

Glyn · « **Reply #2 on:** January 16, 2017, 02:18:19 PM »

It would be better to replace all 8. So on a budget, I would personally say to replace all 8 with an NGK O.E. plug.

Jocko · « **Reply #3 on:** January 16, 2017, 03:27:48 PM »

It was my intention to replace all 8, but using Iridium for the rears and standard plugs for the front. I normally replace my spark plugs every service, but with the difficulty of changing the rears, I thought if I fitted Iridium there, I would only need to replace them every third service.

Glyn · « **Reply #4 on:** January 16, 2017, 04:21:20 PM »

I understand where you're coming from but, how many miles so you do between services? Modern oem plugs should be good for at least 25000. However, just putting iridium in the rears shouldn't have any effect on running. Of course, I could be wrong

culzean · « **Reply #5 on:** January 16, 2017, 04:43:11 PM »

Sounds like a good idea to me to fit Iridium to the rear as they are a pain in the proverbial to replace and a lot of garages don't. They should give rear ignition coils an easier time as well because the blurb says that because of the smaller diameter electrodes they need less voltage to jump the gap, also the gap will stay within specification for much, much longer.

Jocko · « **Reply #6 on:** January 16, 2017, 06:43:51 PM »

I currently do about 9000 miles a year, and have the car serviced by time rather than by mileage. My son-in-law does all the work for me and we have always carried out a "big" service every time, as a matter of course.