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Dorman 42009 Spark Plug Non-Foulers - 18mm Gasket Seat, 2 Pack Universal Fit

Free shipping on orders over $29.99

$12.29

$ 6 .99 $6.99

In Stock

About this item

  • Direct replacement - this spark plug non fouler is designed for easy installation to protect spark plugs from fouling and damage on specified vehicles
  • Ideal solution - this non-fouler preserves spark plug life and is a reliable replacement for an original non-fouler that has failed due to corrosion
  • Durable construction - made from quality components to ensure reliable performance and a long service life
  • Trustworthy quality - backed by team of product experts in the United States and more than a century of automotive experience
  • Cost-effective - has similar performance to part that originally came on vehicle, but is priced far below getting replacement from dealership


This spark plug non fouler is designed for easy installation on specified vehicles to protect spark plugs from fouling and damage. It is engineered for durability and reliable performance.


BAGLIERI Pietro
Reviewed in Italy on March 15, 2022
Ottimo e sicuro con il servizio trasparente.
AJ Kurpjuweit
Reviewed in the United States on August 15, 2021
Installed into the downstream O2 sensor of a 1997 Jeep ZJ that was displaying the 'check engine' lamp and a P0420 fault code. It's been a couple of months now and neither has returned. Engine runs great with no detriment to gas mileage. As shown on many you-tube videos, one of the adapters must be drilled out. I'd advise a drill press and vise for that, a hand job might not provide the satisfaction you want. See how I did that? Seriously, you want to drill dead center and be safe at it. Again, I don't recommend a hand held drill. Once assembled, installation into the cat converter bung is a breeze. Worked for me.
Eyad
Reviewed in the United States on July 28, 2020
If you trying to de foul the oxygen sensor those they won’t work like plug and go ... the oxygen sensor won’t thread inside them because it’s long enough not to let the threads touch each other and they are way far ... so you will have to drill out (one of them )with 1/2 inch drill bit or maybe give it a little more and then stack the other one as is on the bottom ... so they will be like o2 sensor on top then the drilled one then the original one and attach it to the catalytic converter.You need to be aware of something ... they will be long all together so if you don’t have room to suggest to get an elbow shape.P.s: those spark plugs de fouler and you have to do this work .. if you wanna cut the time just buy the o2 de fouler it’s plug and go ... no need to drill anything.Hope this will help you guysUpdate: it didn’t solve the problem either ... I still have check engine light again
C W
Reviewed in Canada on February 1, 2020
I needed a way to mount an O2 sensor for a gauge and this was a very economical way to do it.
Technologic80
Reviewed in the United States on May 7, 2019
So I did a thing. I bought a used, high mileage Prius to tool around with, and well, get 50mpg in the meantime. Lets me keep the miles off my truck. The guy I bought it from was super forthcoming about the Check Engine Light and the "oxygen sensor" that had "gone bad", but I knew better; at 212,000 miles and a known oil burner, the catalytic converter had become marginal, at best. After pricing out converters, on a Prius that I had only paid $2,000 for, I set out for alternatives. Found a great write up on using the Dorman 42009 non foulers on the downstream O2 sensor. Put them on the other day (drilled one of them out with a 1/2" drill bit), cleared the P0420 code, drove around reading live data and holy smokes!! It DOES work. My downstream O2 sensor was reading significant difference than my upstream, which indicates (read: tricks) my ECM into thinking it has a healthy working catalyst, and thus, no more check engine light!! VERY happy with the non-foulers.
Joe Q
Reviewed in Canada on September 10, 2018
it works and described
A good customer
Reviewed in Canada on August 3, 2016
This is truly a no brainer. Couple of bucks to remove that pesky engine light AND pass e-test for my 05 BMW. Required some modification for Bosch 02 sensors, best to buy two per cat drill bottom one out completely hone out the other without losing the bottom hole on the second and use two if clearance allows keep small hole on the first one . Worked like a charm cleared codes and 300km so far no light . I will tell everyone I know who gets a cat efficiency code to get these. Thousands of dollars saved because of metal threaded spacers! Don't ever waste money on new cats. The government can kiss my butt or buy me new cats on their dime (technically my and your dimes) if it wants to. I'll buy these.
Nelson Tang
Reviewed in Canada on May 18, 2015
Definitely a 'must have' item for those wishing to pass their emissions test when it comes to completing the 'catalyst monitor'.This product will literally save you thousands.Consider the cost of replacing the catalytic converter (specifically the ones combined with the exhaust manifold such as the newer models Toyota Sienna).This product is installed downstream of the catalytic converter ' operating below threshold' after drilling a 1/2 " hole through it so as to accommodate the oxygen sensor..It will not affect the performance of the vehicle since it only monitors the performance of the catalytic converter (only the upstream oxygen sensor affects the fuel/air mixture ratio).It will not work with a 'plugged-up converter'.I have used this item several times and it has never failed me.
Emmanuel
Reviewed in the United States on January 21, 2015
Okay, so I know that I as many others buying this product aren't using it as the manufacturer intended, But in terms of getting my truck to pass the Texas state inspection, it totally worked and saved me several hundred dollars.I went to three mechanics prior to installing these and each one said I needed new catalytic converters based on what their diagnostic scanner tool said. I didn't have the money to make the repairs as they were quoted at being $600 plus for replacing the cats.I the car works fine and runs fine, but I couldn't drive around with my inspection sticker being expired. I considered using Sea Foam and other extreme measures like washing the cats or running lacquer thinner through my fuel system to clean out my catalytic converters, but they didn't seem like safe choices. I decided to try this anti Spark plug foulers as many people said they had good success using them to pass the inspection.... And sure enough they were right.It took a couple of days of driving about 50 miles total for the "service engine soon" light to finally turn off.I did have to drill out one of the anti foulers for each o2 sensor with a 1/2" drill bit to get it to fit over the oxygen sensor. It was a bit tough without a vice to hold it in, but clamping it with some plyers while standing on it helped secure it down for me to drill it though. The size threads I needed was 18mm and I have two exhaust pipes so I needed four anti foulers total (2 each).I know that they affect my fuel mixture and will probably be making my fuel economy worse so I will be removing them now that I have passed the inspection and hang on to them for next year. Glad to know that it works!
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