I took my 2010 Volvo XC60 into a third party mechanic for its 150k service.

One part of the service is to replace the spark plugs; they were replaced with Denso Iridium SK20HR-11.

Soon after I noticed that the car had a rough idle while cold.

I had to take the car to the dealer for a new ignition control unit ($500) because it was intermittently not starting, not shutting down, and not ejecting the key.

So that the same time they diagnosed the rough idle as incorrect spark plugs.

I can clearly see on the internet that these plugs are recommended for my xc60.

The dealer wants $300 to put in the "Correct" plugs.

The third party mechanic wants to look at it and was proposing all kinds of other things that it might be.

I have seen a handful of people posting similar problems with Iridium plugs and others that claim they are not a problem.

What do you recommend?

 

$300 to swap out plugs? Sounds like they are quoting list price for the plugs ($115) plus 1.5 hours shop time. Tascaparts.com sells a kit of six for $64. Best thing would be to simply buy the parts online and have your indy mechanic install the Genuine Volvo plugs specific to your model/year. (you didn't mention which engine you have).

The typical complication is that the connectors to the coil packs can get stuck but if they were recently serviced, they should come off easily - and it would be a good time to inspect whether the connectors were damaged during the servicing.

Plan B would be to do the plugs yourself (see below).

https://paulstravelpictures.com/Volv...ide/index.html