Good, bad or ugly? Bosch Spark plugs re: 1994 850 B5254F

Post by **dcarlson12** » 20 Nov 2009, 11:47

Here is the Bosch site list of available spark plugs:

4503 PLATINUM IR FUSION Do not gap. Gap is not adjustable.
4303 PLATINUM+2 Do not gap. Gap is not adjustable.
4228 PLATINUM GAP=0.028"
7555 SUPER GAP=0.028"
7955 SUPER PLUS GAP=0.028"
4417 PLATINUM+4 Do not gap. Gap is not adjustable.
4028 PLATINUM PLUS GAP=0.028"

I believe the 7555 is what was originally used on the vehicle.
Can anyone confirm?
And can anyone relate good, bad or ugly experience with any of the plugs?

Post by **tjts1** » 20 Nov 2009, 12:22

Bosch plugs are garbage. Get NGKs.

Post by **Ozark Lee** » 20 Nov 2009, 14:19

The 7555 or 7955 will work fine. I run FR7DC which was the old number for the 7555 in my N/A cars and they work great. They don't last all that long - 20 to 30 k - but at a fuzz over $1.00 each, who cares.

Any of the +2 or +4 plugs will screw into the head but they won't work. The gap is too large.

Be sure to gap any of them that you buy, they will come out of the box at around 0.035 to 0.040.

...Lee

jimmy joe · Post by **jimmy joe** » 15 Nov 2010, 06:52

the 7555 plugs are stock and the 7955 ones are supposed to replace them, though I notice that the 7955s have a "slotted" electrode.
Any concerns about this?

Post by **jblackburn** » 15 Nov 2010, 06:54

No idea what the reasoning behind that is, but they work just fine.

Post by **erikv11** » 15 Nov 2010, 08:18

In my NA I've used both the 7555 and the Volvo OEM and can see absolutely no difference.

Post by **misha** » 15 Nov 2010, 16:06

erikv11 wrote:In my NA I've used both the 7555 and the Volvo OEM and can see absolutely no difference.

Oem ones lasts much,much longer!

Post by **cn90** » 23 Jul 2012, 23:22

dcarlson12 wrote:Here is the Bosch site list of available spark plugs:
7555 SUPER GAP=0.028"
7955 SUPER PLUS GAP=0.028"

Ozark Lee wrote:The 7555 or 7955 will work fine. I run FR7DC which was the old number for the 7555 in my N/A cars and they work great. They don't last all that long - 20 to 30 k - but at a fuzz over $1.00 each, who cares...

Bringing back old but important thread.

I was at local Autozone, they do not carry Bosch 7555, instead they have Bosch 7955 (Super Plus) for $1.99/each.
I visually inspected the 7955, it clearly said "FR7DC, Made in Brazil".

PS: The current spark plug (7555) has about 40K miles on it, the gap increased from 0.028" when new (I re-gapped the new plugs 40K miles ago) ---> 0.040". I think this increase in gap is normal after 40K miles.

Anyway, at $10 for a set of 5, it is a bargain! I will give the Bosch 7955 a try and report back.

Post by **phat78ta** » 24 Jul 2012, 09:42

I run the ngk non iridium plugs in mine, and they work great. I think I went 2 years on this last set, including track runs. They still had .28 gap, and very little wear on the ceramic. I replaced them for peace of mind on vacation trip.

Post by **cn90** » 24 Jul 2012, 10:17

phat78ta wrote:I run the ngk non iridium plugs in mine, and they work great. I think I went 2 years on this last set, including track runs. They still had .28 gap, and very little wear on the ceramic. I replaced them for peace of mind on vacation trip.

What is the NGK PN?