Engine: B5244: Spark plug length in 2.4 T5 2005 V70

[VroomVroomClonk]

I'm trying to replace my spark plugs for the first time in this car since I've owned it, and I've found that the new plugs are much longer than the existing ones (see attached photo).
The new ones are Bosch FR7NI33 with a threaded length of about 26mm and the old ones are Volvo 30637308 with a threaded length of about 18mm.
A search on the internet does find several places that say the longer ones are correct, including the Bosch online catalogue.
However I'm very hesitant to fit a plug that is so much longer than the one I'm removing, so can anyone here confirm please if this longer plug really is the correct one?
Also, if the longer one is correct, do people think that the lower part of the thread in my cylinder head could now be sufficiently damaged or full of carbon from being exposed to combustion for thousands of miles that I should actually now stick with a shorter plug even if it is the wrong one?

Many thanks.

[oragex]

I'd be aware that a good percentage of internet sites, even the most popular ones, are messed up when it comes with parts compatibility for this car. Many of them repeat the same error for the same part. It's really a big mess with these numbers, sometimes even the main dealer will make mistakes.

I've never seen the longer version. If it's incorrect it may kick a valve or worst the piston, not sure how much space is left between the plug and the top of the piston.

[VOLVOBOY]

Hi.
The plugs for T5`s and R`s are the long reach type - 26.5mm.
Your Bosch number is correct.
The Volvo number has been replaced by 30751806.
If you`re still not convinced.. put one plug in and crank the engine very slowly by hand, take the plug out again and look for evidence of contact.
If there`s major interference you won`t be able to turn the engine.
If it`s minimal there will be some "bruising" of metal on the piston crown which you probably won`t be able to see but there will be evidence on the plug.

[VroomVroomClonk]

Originally Posted by VOLVOBOY

Hi.
The plugs for T5`s and R`s are the long reach type - 26.5mm.

Did the 2.3 T5's have short plugs which then changed to long plugs on the 2.4 T5's?

[VOLVOBOY]

Someone more knowledgeable than me will have to answer that. All I can say is that I`ve owned a 2.3 T5 for the last ten years. I went through all this , like you , when I first got the car.
It seems to me , but I may be wrong, that the change came with the P2 2.4 Facelift in 2005. Prior to that it was the shorter plug. I have the shorter plug in mine.

[oragex]

Out of curiosity, googled up about this with the following results.

Again, can't emphasis enough, I never blindly trust what these online sites say about compatibility.

https://www.ipdusa.com/techtips/1001...r-p1-p2-volvos

And a few discussions on forums

http://forums.swedespeed.com/showthr...71-vs-30751806

https://volvoforums.com/forum/volvo-...k-plugs-57369/

[MMT5]

My 2007 2.4 T5 has the longer reach plugs.

[ASt85]

It may sound obvious but why would you want to change from using Volvo plugs? What little you might save in fitting Bosch plugs will be lost even if they do fit as they will not last as long as the genuine Volvo ones.

Which ever company manufactured the Volvo plugs for your engine they will still outlast the matching spec ones from that manufacturer. Which sounds unlikely but Bosch and NGK branded plugs have started misfiring within a few thousand miles in Volvos I have owned; when replaced with the Volvo plugs, the misfire disappeared until they have been replaced at the much longer service interval. It is one of those service parts where it really does make sense to use the Volvo product. I know some of the ignition parts/exhaust sensors etc. are of Denso origin but have no direct experience of Denso plugs in Volvo engines.

You also know that it is definitely the right plug for your engine; if you buy it from the Volvo dealer the plug length should be the correct one for your engine even if Volvo have changed the spec.

[VroomVroomClonk]

Originally Posted by ASt85

It may sound obvious but why would you want to change from using Volvo plugs? What little you might save in fitting Bosch plugs will be lost even if they do fit as they will not last as long as the genuine Volvo ones.

I bought all the parts for this service from my local independent motor factor before I realised this sparkplug minefield existed. However, having said that, I've bought all my service parts for all my cars from this same place for the last 15 years and they have never supplied me with one incorrect bit in all that time, nor have any of the parts they've supplied ever failed to perform perfectly for their full service interval. Looking at the old Volvo and new Bosch plug in front of me now, the colour, shape and material of the connection nipple at the top is identical on both. The colour and shape of the ceramic including the profile and position of the ridges is identical. The machining of the metal nut part is identical. The font used to stamp the word GERMANY into the side of the metal is the same. And from what I can see of the old electrode compared to the new they are the same as well. I'd be pretty confident to say that this Volvo plug in front of me was made by Bosch. Now I'm happy to accept that even if it was made in the same factory, it doesn't necessarily mean it was made to the same specification. But now I've bought them, I think I may as well try them and find out.

Originally Posted by ASt85

You also know that it is definitely the right plug for your engine; if you buy it from the Volvo dealer the plug length should be the correct one for your engine even if Volvo have changed the spec.

Yes, I would have hoped so. My car was owned by Volvo themselves for the first couple of years and then by one other private owner since then until I bought it last year. It has a fully stamped service book all done by Volvo main dealers or an independent Volvo specialist. And yet it was fitted with the wrong spark plugs when I bought it.
And indeed a quick Google now finds This advert from Caffyns Volvo offering "GENUINE VOLVO SPARK PLUG PLUGS 850 S70 V70 S60 XC90 PETROL TURBO 8692071" which they claim is "SUITABLE TO FIT - 850 V70 S70 S60 S80 XC90 ; MODEL YEAR 1994 > WITH PETROL TURBO ENGINES". But that is wrong, as they are not the correct ones for a 2.4 T5.

Also, the second and third links in the post from oragex above both say that Volvo dealers have fitted the wrong plugs, so this does seem to be a major mess!

[VroomVroomClonk]

Originally Posted by oragex

Out of curiosity, googled up about this with the following results.

Again, can't emphasis enough, I never blindly trust what these online sites say about compatibility.

https://www.ipdusa.com/techtips/1001...r-p1-p2-volvos

Yes, I thought I'd struck gold when I found that one, but as far as I can see it contradicts itself.

It starts off by saying "Prior to 2004, there was basically one length plug that fit in all FWD & AWD models. In late 2004, Volvo introduced a different cylinder head that was thicker between then combustion champer and the spark plug seat. This difference means that these engines use different spark plugs and shorter ignition coil packs." Which all sounds good (except for the typos!). But it then goes on to say "The thicker head appears on all P1 models and later P2 models (S60 T5, V70 T5, S60R & V70R models.)". So now I'm confused as I though the P1 was the one that started in the mid 90's and certainly earlier than 2004 so how can they have the thicker head and longer plugs when their sentence before had said that all plugs were the same prior to 2004. This is a USA site though, so does P1 and P2 mean different years / models over there?