96 850 Turbo Just installed Denso Iridium Spark Plugs

Post by **RussB** » 29 Jul 2014, 15:03

SK20PR-L11 (3443) to be exact. I had been running Volvo branded platinum plugs for 11 years, never had an issue...until last spring. Bought a set from FCP in April, along with wires, cap & rotor. The car suddenly crapped out one day in May. It was running rough, throwing misfire codes. I could find nothing wrong. I had it towed to my favorite repair shop. They found one Volvo plug had a hairline crack and was misfiring. He installed one Denso Iridium (all he had that matched) and the car has been great for over a year.

I felt like changing the plugs "just because" and am now leery of the Volvo plugs, so I'm trying the overpriced Denso Iridium's. The Denso Iridium's came gapped at .044". I reset them to .028". I'll let you all know if they suck.

Post by **cn90** » 29 Jul 2014, 15:12

Denso Iridium has its own issues.

If you ever go with Iridium, stick to NGK. I posted the DIY for my 2005 XC90 2.5T below:
https://www.matthewsvolvosite.com/forums ... 10&t=64080

Post by **abscate** » 29 Jul 2014, 17:42

Russ - would you happen to still have that cracked plug? Interested for a work project.

Post by **RussB** » 29 Jul 2014, 17:51

cn90 wrote:Denso Iridium has its own issues.

If you ever go with Iridium, stick to NGK. I posted the DIY for my 2005 XC90 2.5T below:
https://www.matthewsvolvosite.com/forums ... 10&t=64080

What the Denso plug issues in the T-5's?

Like I said, my car ran a single Denso Iridium (albeit a SK20R11) for over a year in cyl #2. That plug was gapped at .042". Apparently the mechanic never re-set the gap to .028" (which I had to do with the new Denso Iridium's)

The only problems I ever had was with Bosch Platinum FR7DP (4028) which would misfire and throw codes under wide-open-throttle (WOT) with 12+lbs of boost. Took them out mighty fast

Post by **RussB** » 29 Jul 2014, 17:55

abscate wrote:Russ - would you happen to still have that cracked plug? Interested for a work project.

No, I don't. Like I said, it all went down over a year ago and my mechanic swapped it out. As a side note, he said that he sees new, defective/cracked plugs with some regularity. For the life of I can't remember which brand was worst (it wasn't Bosch, who I believe makes the factory Volvo turbo plugs for my car. They're marked Made in Germany)

Post by **northernlights** » 29 Jul 2014, 19:34

RussB wrote: I felt like changing the plugs "just because" and am now leery of the Volvo plugs, so I'm trying the overpriced Denso Iridium's. The Denso Iridium's came gapped at .044". I reset them to .028". I'll let you all know if they suck.

I like the overpriced NGK Iridiums. Here's a link to a topic describing my experience with them in my 94 850 Turbo.

https://www.matthewsvolvosite.com/forums ... =5&t=62504

Post by **phat78ta** » 29 Jul 2014, 19:49

I run the regular ngk plugs in both my cars (when they actually run..) and have had nothing but great results. The 855 turbo that is making me hat volvo right now ran like a stabbed rat at @15 psi boost with no issues.
The plain ngk plugs are waiting for their home in the fresh rebuild as we speak.

Post by **cn90** » 29 Jul 2014, 20:40

RussB wrote:...What the Denso plug issues in the T-5's?

Below is one anecdotal experience:
http://volvospeed.com/Review/performanc ... plugs.html