Why Bosch Plugs Suck! - Toyota

004Gunner · 11-24-2009, 06:33 PM

I read the part of the manual that says to only use dual electrode plugs but apparently skipped over the part that says to use Denso or NGK. I had a P0305 cylinder 5 misfire and found that the Bosch Platinum plug had both electrodes burned off. These are rated for 60k miles and only had 38k miles on them.

Ulfr · 11-24-2009, 06:55 PM

Interesting, I'll take it as the plug on the right is the bosch one, right?

Looks like the thread to it has been abit lose, at least all that soot shouldn't be there, and the cathode looks burned and melted...

I suppose it's an isolated case, no?

Never used bosch one's and I wont be changin' these things for the next few million miles in my Runner *grin*

004Gunner · 11-24-2009, 07:09 PM

Quote:

Originally Posted by Ulfr

Interesting, I'll take it as the plug on the right is the bosch one, right?

Looks like the thread to it has been abit lose, at least all that soot shouldn't be there, and the cathode looks burned and melted...

I suppose it's an isolated case, no?

Never used bosch one's and I wont be changin' these things for the next few million miles in my Runner *grin*

They're actually both Bosch plugs and yeah the soot covered one was loose as hell. The plugs were tightened to the torque specs and the crush washer was flat, but somehow it still came loose. The plug for cylinder 2 was so loose that the boot wouldn't seat properly. I caught that issue about 10k miles ago. The cleaner looking plug pictured had a loose terminal nut. So I think it's safe to say that these plugs failed on every level

CJ3Flyr · 11-24-2009, 07:14 PM

On the Denso's I just put in the box congratulated me for purchasing the finest plugs made... I know that's a combo of marketing, arrogence but there is truth in the claim.

In my entire life I have had good and bad experiences with all brands of plugs except Denso and NGK, just good with those two.

Good luck and FYI: I just put in the Iridium Denso into my '07 V6 and couldn't be happier.

004Gunner · 11-24-2009, 07:20 PM

Quote:

Originally Posted by CJ3Flyr

In my entire life I have had good and bad experiences with all brands of plugs except Denso and NGK, just good with those two.

Yeah I always used NGK in my dirt bikes and jetskis. NGKs are in the Runner now and I can't remember why I got the bosch plugs in the first place

CJ3Flyr · 11-24-2009, 07:24 PM

Quote:

Originally Posted by 004Gunner

...and I can't remember why I got the bosch plugs in the first place

I've done it too... I attribute it to a momentary lapse of reason; not unlike 2am at a bar

Pikeman · 11-24-2009, 07:51 PM

Now for the Happy news, those burnt off electrodes had to go somewhere......Hoefully they arent doing any damage. I had crappy luck with the Boschs on other Yotas and wont run them but on a Small block Chevy Carb they worked fine for me though. I will be doing the Denso plugs myself soon along with Factory OEM wires.

004Gunner · 11-24-2009, 07:59 PM

Quote:

Originally Posted by Pikeman

Now for the Happy news, those burnt off electrodes had to go somewhere......Hoefully they arent doing any damage. I had crappy luck with the Boschs on other Yotas and wont run them but on a Small block Chevy Carb they worked fine for me though. I will be doing the Denso plugs myself soon along with Factory OEM wires.

I'm hoping they passed through the exhaust and are not "honing" my cylinders. I'm glad it's an iron block and not aluminum though. I think that makes the prognosis a little better

Pikeman · 11-24-2009, 09:39 PM

Sorry maybe shouldnt have pointed that out. I honestly hope that they slowly disentigrated and didn't harm anything.

Elton H · 11-24-2009, 10:50 PM

and this is why everyone one should use only ngk or oem denso not bosch or fram or anything other crap

eskimochaos · 11-25-2009, 12:27 AM

The quality of EVERY Denso OEM component in the 4R blows EVERYTHING after market out of the water. Including plugs, oil filters, and the entire ignition system.

004Gunner · 11-25-2009, 10:33 AM

Quote:

Originally Posted by Pikeman

Sorry maybe shouldnt have pointed that out. I honestly hope that they slowly disentigrated and didn't harm anything.

That's exactly what should be pointed out! It proves that inferior products have consequences if you choose to use them. Bosch makes some of the best power tools I've used, but they completely fail when it comes to spark plugs. Hopefully my 33% plug failure rate will show others why Denso and NGK are the only plugs that should be used

Thai · 11-25-2009, 10:51 AM

Quote:

Originally Posted by 004Gunner

That's exactly what should be pointed out! It proves that inferior products have consequences if you choose to use them. Bosch makes some of the best power tools I've used, but they completely fail when it comes to spark plugs. Hopefully my 33% plug failure rate will show others why Denso and NGK are the only plugs that should be used

004Gunner...i have moved this thread to MAINTENANCE and made it a sticky so that everyone can see from your experience with non-OEM plugs. I have also left a re-direct to this thread in the GENERAL section. If you have objection to this, then please PM me and i will move it back.

Thanks.

004Gunner · 11-26-2009, 11:19 PM

Quote:

Originally Posted by Thai

004Gunner...i have moved this thread to MAINTENANCE and made it a sticky so that everyone can see from your experience with non-OEM plugs. I have also left a re-direct to this thread in the GENERAL section. If you have objection to this, then please PM me and i will move it back.

Thanks.

No objections here! Thanks Thai! I also think it's important to add that I had a ticking sound from the engine that was most noticeable during idle speeds. It sounded like a valve tick or an exhaust leak and had been getting slightly worse over time. LINY4Runner and JohnsD90 both heard the ticking while at the northeast meet. After putting hundreds of miles on it since putting in the NGK plugs, I can safely say that the ticking is gone and was also a result of the Bosch plugs. I would've never thought that plugs would be the cause, but if anyone has this ticking issue I would suggest checking the plugs. If someone other than you has done your tune up then it's possible the wrong plugs are in there.

SSt4r · 11-27-2009, 12:17 AM

Probably hearing the exhaust blow-by on the loose plug(s). Glad you found it.

11-24-2009, 06:33 PM	#1 (permalink)
004Gunner Registered User Join Date: Mar 2008 Location: Dirty Jersey Posts: 1,406	Why Bosch Plugs Suck! I read the part of the manual that says to only use dual electrode plugs but apparently skipped over the part that says to use Denso or NGK. I had a P0305 cylinder 5 misfire and found that the Bosch Platinum plug had both electrodes burned off. These are rated for 60k miles and only had 38k miles on them. Attached Images __________________ '00 4Runner Limited 4x4 3.4 L V6 w/ Rear Differential Locker "Once banned, twice shy"

11-24-2009, 06:55 PM	#2 (permalink)
Ulfr Icelandic Toyotiac! Join Date: Oct 2006 Location: Iceland, Seltjarnarnes Posts: 426	Interesting, I'll take it as the plug on the right is the bosch one, right? Looks like the thread to it has been abit lose, at least all that soot shouldn't be there, and the cathode looks burned and melted... I suppose it's an isolated case, no? Never used bosch one's and I wont be changin' these things for the next few million miles in my Runner grin __________________ - Sinc, Ulfr ---------- Rigs: Undanfari I - '90 4Runner V6 38" - 1"/2" lift - rollover, in rebuild Undanfari II - '94 4Runner TD 44" - 3"/3" lift - The daily driver. ;) Undanfari II's gallery Mitzy - '90 MMC Colt 1.5I4

11-24-2009, 07:14 PM	#4 (permalink)
CJ3Flyr Super Moderator Join Date: Jan 2008 Location: Metro ATL & Cape Coral, FL Posts: 5,848	On the Denso's I just put in the box congratulated me for purchasing the finest plugs made... I know that's a combo of marketing, arrogence but there is truth in the claim. In my entire life I have had good and bad experiences with all brands of plugs except Denso and NGK, just good with those two. Good luck and FYI: I just put in the Iridium Denso into my '07 V6 and couldn't be happier. __________________ Chris 07 Salsa SR5, 4wd Cyclone pre-cleaner , Aux Transmission Cooler, Hidden Hitch 70779 (600/6000lbs, WDH=730/7300lbs), AirLift 1000, FJCruiser front springs (& now rear too!), Axle Vent Mod, Swaybar Bushing Upgrade, V6 Tick Reduction, VSC off mod, Maplight Mod, 255/75/17 Goodyear Wrangler SAs, Tailpipe Mod

11-24-2009, 07:51 PM	#7 (permalink)
Pikeman Registered User Join Date: Oct 2008 Location: So. Cali Posts: 922	Now for the Happy news, those burnt off electrodes had to go somewhere......Hoefully they arent doing any damage. I had crappy luck with the Boschs on other Yotas and wont run them but on a Small block Chevy Carb they worked fine for me though. I will be doing the Denso plugs myself soon along with Factory OEM wires. __________________ 1998 T4R SR5 K&N FIPK, S.S 1.2 rear only, All-Pro front coils and UCA, All Pro Sliders, Baja Rack, Custom rear bumper, 285/75/16 NTG's on Ivan Stewarts. Aussie Locker and 1st gen roll bar mod. Still need front bumper w/ winch and skids.

11-24-2009, 09:39 PM	#9 (permalink)
Pikeman Registered User Join Date: Oct 2008 Location: So. Cali Posts: 922	Sorry maybe shouldnt have pointed that out. I honestly hope that they slowly disentigrated and didn't harm anything. __________________ 1998 T4R SR5 K&N FIPK, S.S 1.2 rear only, All-Pro front coils and UCA, All Pro Sliders, Baja Rack, Custom rear bumper, 285/75/16 NTG's on Ivan Stewarts. Aussie Locker and 1st gen roll bar mod. Still need front bumper w/ winch and skids.


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11-24-2009, 10:50 PM	#10 (permalink)
Elton H Registered User Join Date: Dec 2008 Location: Siletz.OR Posts: 1,284	and this is why everyone one should use only ngk or oem denso not bosch or fram or anything other crap __________________ 98 4runner sr5 3.4L 5spd 4x4 e-locker Clicky For Mods

11-25-2009, 12:27 AM	#11 (permalink)
eskimochaos Im Opinionated mmK? Join Date: Apr 2008 Location: North Jersey Posts: 1,833	The quality of EVERY Denso OEM component in the 4R blows EVERYTHING after market out of the water. Including plugs, oil filters, and the entire ignition system. __________________ \| 2007 V8 SE \| 265/70/17 BFG KO's \| Complete Alpine + Kenwood Audio System \| 20% Front, 5% Rear Tint \| M1 All Around \|

11-27-2009, 12:17 AM	#15 (permalink)
SSt4r Registered User Join Date: Aug 2008 Location: southeastern MA Posts: 94	Probably hearing the exhaust blow-by on the loose plug(s). Glad you found it. __________________ There is no spoon. 2005 sport 4X4 black

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