Bosch spark plugs = Ok ?

If you do not want to purchase the correct NGK or Denso plugs, you at least should purchase an iridium spark plug model for better service life.

 

The iridium Bosch plugs should be fine but the platinum will not last as long. Bosch products are usually of good quality.

 

About ten years ago, the Bosch platinum plus plugs had quality control problem. The gas seal is leaking after a few thousand miles. Hot gas is leaking through the plug inside body causing low resistance and subsequently misfiring.
I stopped buying Bosch plugs since.
I hope they have fixed this problem by now.

 

I would have to really dislike you to install those in your Prius. Myself, as well as many others int the automotive repair community do not like those plugs. For example, I am a member if iATN.net which has a forum like this one. A few weeks ago people were talking about refusing to install Bosch spark plugs when asked to do so by their superiors. When we come across a vehicle with an engine problem and find those plugs, removing them is often the first thing we do. I would recommend you get the Denso SK16R11 (AKA #3324) as you can't go wrong with the ones the car came with.

 

Except spark plugs. The ones they sell at the auto parts stores (here) are if inferior quality compared to those they sell the manufacturers.

 

I agree. Bosch has a very poor rep for sparkplugs. Spend the money and get the Denso or I would bet the NGK's are easier to find. Its alot of work to replace the plugs. It would be irritating to have to go back and replace them 5k miles later.

 

I myself love using E3 spark plugs.

 

If the ones that are currently in your car lasted for 100,000 miles???
I'd do that again.
Really.....the price difference can't be all that much for 4 plugs!
Spread out over 4-5 years and 100,000 miles?

Good luck!
Let us know what you pick.

 

I have to agree with Avi, Get the Denso's, they are worth it. The engine was designed and tested with them.

 

Bosch plugs are generally bad news. Stay with the correct Denso or NGK plugs.

 

I figured this thread should have a link to Hybrid Car Solutions, Miami Fl | PriusChat on it.

 

It never fails, or hasn't failed yet, that when I am thinking about a maintenance issue with my car there will be a post about the subject in PC. I've passed the 120K mark and thinking about the recommended spark plug replacement. No issues with missfire or noticable changes in MPG to act as encouragement. Might just wait a little while longer. I drive all highway miles, 65-75 mph, and log 700 miles a week on my commute.

 

I believe that the engine ECU will not log a misfire code until the plug has a 25% or greater misfire rate. That is a lot of unburnt fuel leaving the exhaust manifold and heating up the catalytic converter.

 

I think that's a bit excessive. If this ECU is anything like Toyota's ECUs from the late 90s, the MIL is illuminated after X misfires in 200 revs of the crankshaft, where X can be anything from 10-30. There's also a second stage code that is thrown after Y misfires in 1000 revs of the crankshaft, and I forgot what Y would be... but it's much less than 25%. I'd say it's closer to 10%.

 

As is true with most things having to do with Prius, the engine ECU logic in deciding to log a P030x code is fairly complicated. Here are two criteria used:

1. A cold-start misfire rate of 2% or more will log a DTC
2. 108 or more misfires in 200 revolutions will log a DTC

Regarding the criteria in #2, since two spark plugs fire per crankshaft revolution, then 108 misfires are required out of 400 spark plug ignition events, which is ~25%.

 

I wonder why they found such a high rate acceptable... this doesn't make sense from a standpoint of dumping unburnt fuel into the cat...

 

FWIW, a lot of engines made overseas (certain GM & Saab for example) come with Bosch in from the factory and are the recommended replacements. We had a Saturn with the Opel based v6 that wouldnt run right with ANYTHING but a Bosch +3 spark plug.

Not all Bosch spark plugs are garbage. Would I use them in my Prius? Nope, not unless they were OEM factory plugs and they arent. I always stick to the plugs the manufacturer put in.

 

Keep in mind that the Bosch you can get a the auto parts store are not the same as the ones used by manufacturers. For example I have never seen a +3 spark plug at my local auto parts store, only +2 and +4.

 

Im aware of this but others might not be.