1998 V70 Spark plugs look dirty, but are they normal?

Post by **theWIFES_S70** » 06 Nov 2015, 10:03

Hey, just a quick question and clarification. Is it commonly suggested around here that you should always run the Volvo OEM Turbo spark plugs in all N/A P80s?

brunocerous · Post by **brunocerous** » 06 Nov 2015, 11:16

cn90 wrote:Stay away from Denso plugs, they are known to break the tip off (Search Volvospeed).

- Switch to NGK Iridium BKR6EIX and you will never look back.
- Although Iridium plug is $7/each (Advance Auto Parts), Iridium easily lasts some 100K. The car will run very smoothly, you may see better fuel mileage.

Thanks so much for the tip. I was a little shocked to find Denso plugs in there and definitely won't be buying them. I just ordered an NGK set and will pick them up later today! I'll update after I install and try them out.

Post by **rguzz** » 06 Nov 2015, 12:30

I'm going to go out on a limb and maintain that replacing the plugs will be a quick fix and that they will foul again. I like the leaky injector suggestion. How old are they? Is CTS a zillion miles old? Any evidence aside from the plug appearance that the car has been running rich? I suppose the non oem plugs you have in there could be entirely responsible for what you are seeing but I'm suspicious there is a yet to be an underlying issue. Admittedly, I'd probably do just what you are doing, but would maintain a nagging suspicion that there is still something awry. Good to get lucky, though!

Post by **RussB** » 06 Nov 2015, 19:21

How old are the spark plug wires, cap & rotor? Bougicord & Bosch?

Is the ignition coil strong?

Does the car burn any oil?

Those are the proper plugs. It's not a spark plug issue...heck, the plugs aren't THAT bad

Sommerfeldt · Post by **Sommerfeldt** » 07 Nov 2015, 10:18

RussB wrote:Those are the proper plugs. It's not a spark plug issue...heck, the plugs aren't THAT bad

They're Volvo plugs, no question about that, but I thought there was a general agreement that the multi electrode plugs are not these engines' favorites...
Those are the worst plugs I've seen out of a Volvo after just 2 months of running.

- S

Post by **dosbricks** » 07 Nov 2015, 12:20

RussB wrote: Those are the proper plugs. It's not a spark plug issue...heck, the plugs aren't THAT bad

+1
Three ground prongs are Volvo spec for an NA. NA runs well on them. I change about every 30k.

Single ground copper are for turbo.

Light tan ashy residue is desirable = fuel/air mixture correct. Those look like the engine is running rich.

Post by **cn90** » 07 Nov 2015, 13:05

The Volvo OEM plugs are overpriced.
Once you use the NGK Iridium, you don't go back to copper or Volvo OEM plugs.

Post by **erikv11** » 07 Nov 2015, 13:31

Thread is a little all over the place ...

- no, it is not good practice to use the turbo plugs in a non-turbo car. Not recommended at all, ever. The first few responses in this thread seem to have not noticed the car is NA.
- yes, the OEM plug for the NA is 3-prong
- the OEM plugs are about $5 each and proven to be superb over the last 20 years, how is that overpriced compared to a $7 iridium??? You will easily get 40k from the OEM, 3-prong plug.
- agreed, there is likely no plug issue at all here, the new plugs are just fine no need to replace.

Among other things the residue on those few plugs could be oil, due to leaky valve stem seals. Any smoke when revving after prolonged idle, or on startup? Injector idea is reasonable but you can't clean them yourself.

Post by **RussB** » 07 Nov 2015, 15:01

erikv11 wrote:Thread is a little all over the place ...

As are ALL spark plug threads. Brings out the crazy in people!

erikv11 wrote:- no, it is not good practice to use the turbo plugs in a non-turbo car. Not recommended at all, ever. The first few responses in this thread seem to have not noticed the car is NA.
- yes, the OEM plug for the NA is 3-prong
- the OEM plugs are about $5 each and proven to be superb over the last 20 years, how is that overpriced compared to a $7 iridium??? You will easily get 40k from the OEM, 3-prong plug.
- agreed, there is likely no plug issue at all here, the new plugs are just fine no need to replace.

Among other things the residue on those few plugs could be oil, due to leaky valve stem seals. Any smoke when revving after prolonged idle, or on startup? Injector idea is reasonable but you can't clean them yourself.

It looks like oil to me, but the condition of the rest of the ignition system must be at "stage zero" too.

Post by **matthew1** » 07 Nov 2015, 16:06

1998 V70 Spark plugs look dirty, but are they normal?

Re: 1998 V70 Spark plugs look dirty, but are they normal?