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I see advertising for Iridium spark plugs. Is there any benefit to them as opposed to ordinary spark plugs.

Neil.

From the "Ask Jack" archives - 14 December, 2009

It depends on the application as to the benefits in my view.

Some manufactures have designed their engines in such a way that spark plug removal / replacement is a major job.

In some cases it can almost be an engine removal exercise such is the lack of access to the plugs, more so with the front wheel drive V6 power units.

In this scenario the plug replacement period can be upwards of 100,000kms and the iridium or platinum type plugs can tolerate and operate efficiently at these levels. So its not so much about enhanced performance, its more reducing maintenance costs and retaining performance levels in many applications.

Since the introduction of unleaded fuel in NZ even the standard spark plug life has been extended to new levels. Most standard plugs will last up to and beyond 40,000kms in some cases without causing any problems or placing too much extra load on the ignition systems.

If for some reason you wanted to fit new plugs and forget about them, then its worth consideration I guess, but you would have to be keeping the car for a long time to gain financially. The cost of these spark plugs can be horrendous in comparison to the standard manufactures recommendation