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When is the right time for new spark plugs on SLK 320 (2001)


I have a 2001 SLK 320. It has 48k miles on it. I’ve bought it used in 2005. It had 6k miles on it when I bought it. So it spent its early years kept in a garage. For the next 5 years I have been driving it everyday to work, but my commute is short. So it only has 48k on it.

My question is when is a good time to replace the spark plugs, given my circumstances. The normal thing to do would be to replace them at 7th year, but I didn’t do it then because of the extreme low mileage. And then I forgot about it. Now it is 10 years old. I wonder you guys think?

I want to do the job myself. So my other question is what is the recommended “spark plug gap” for this car and what is the torque specification?

Phoenix Tong

This car probably has platinum or iridium plugs in it. Good for 50-100k miles.
The new plugs will come gapped. Don’t try to adjust.
The best bet is to stick with the same brand and part# plug it came with.
Now’s a good time to change them. Mainly so they won’t get stuck in place.

Thanks for the reply.

This car does have platinum. Anyone know the torque setting to use?

Another item I am wondering if I should replace is the poly-v-belt, which is also original.


At 10 years I would change the belt, radiator hoses and thermostat.
Inspect the rubber brake hoses and the rubber boots on suspension parts.