Why Bosch Plugs Suck!

004Gunner

004Gunner

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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.
 

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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*
 
Ulfr said:
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*
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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
 
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.
 
CJ3Flyr said:
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.
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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
 
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.
 
Pikeman said:
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.
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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
 
Sorry maybe shouldnt have pointed that out. I honestly hope that they slowly disentigrated and didn't harm anything.
 
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.
 
Pikeman said:
Sorry maybe shouldnt have pointed that out. I honestly hope that they slowly disentigrated and didn't harm anything.
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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 said:
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
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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.
 
Thai said:
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.
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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.
 
Sorry to have found this sticky! I have the Bosch platinum 4 in my truck. So I may have 4 electrodes to come of in my engine!? whoo hoo. Recommended by
Auto Zone. Man, I am an idiot.
 
Well, now I am wondering whether I have screwed up or not. I live so far from a Toyota dealer it's not even funny. My wifes 4 Runner has 64 K and I figured it probably needed new plugs. I remembered you guys saying not to get Bosch plugs, so they were out. And the Auto zone did not have Denso or NGK. So I got Autolite platunum. But I can tell you that I could literally feel the difference in power after I installed those plugs. They were not what I wanted, but I figured they would be better than the ones that were in it.
I did not tell my wife that I thought it ran better, I just told her that it had new plugs. After she drove it, she commented on how much better it ran. The Autolite plugs are just the single electrode, fine wire platinum type.
I think these plugs just agree with the V6 motor. Now we will just have to see how long they last!
 
i have a 1999 sr5 2wd. when i replaced my plugs i noticed i had dual electrodes, but i installed the NGK single electrodes...will this make a difference?
 
bak3rme said:
i have a 1999 sr5 2wd. when i replaced my plugs i noticed i had dual electrodes, but i installed the NGK single electrodes...will this make a difference?
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I'm pretty sure the 3rd gen really needs the dual prong to work properly... You may get a CEL. Maybe a 3rd gen guy will chime in.
 
747ifly said:
Sorry to have found this sticky! I have the Bosch platinum 4 in my truck. So I may have 4 electrodes to come of in my engine!? whoo hoo. Recommended by
Auto Zone. Man, I am an idiot.
Click to expand...

I just put the same plugs in mine. 4 prongs. Should I get rid of them?
 
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