Bosch HR6DS spark plugs - went obsolete in 2019 with no replacement

[82DMC12]

Last week I found it difficult to find Bosch HR6DS plugs locally. A couple websites I checked like SparkPlugs.com said the part was discontinued. I called Bosch this morning and they confirmed it was discontinued in 2019 with no replacement in the works. Just a slow mover.

I'll be buying from a vendor now but just wondering how others are dealing with this problem? I know the coating on the HR6 was helpful for keeping the plugs from sticking in the heads and other brands like Autolite crossovers don't have it and can be a real scary experience trying to remove.

What is the 2021 consensus replacement?

[dmcman73]

Last week I found it difficult to find Bosch HR6DS plugs locally. A couple websites I checked like SparkPlugs.com said the part was discontinued. I called Bosch this morning and they confirmed it was discontinued in 2019 with no replacement in the works. Just a slow mover.

I'll be buying from a vendor now but just wondering how others are dealing with this problem? I know the coating on the HR6 was helpful for keeping the plugs from sticking in the heads and other brands like Autolite crossovers don't have it and can be a real scary experience trying to remove.

What is the 2021 consensus replacement?

Most of the newer sparkplugs have that coating on the threads. If you are concerned, apply a tiny dab of copper grease or anti seize grease to the threads, but, just be carful torque them in as grease will cause you to torque it at a higher level.

As for replacement, I'm actually going to try NGK 2238 plugs (should have them in a day or two from Rockauto), they are copper plugs and are cheap and the same ones that DMCH sells. These engines don't really need anything fancy in them.

[David T]

The PRV seems fussy about what plugs you put into it. One option is to sandblast the old plugs and regap them. For most of us we don't put so many miles on the car so the plugs should last a long time. This is a problem all up and down the parts chain. As the cars age even parts that were plentiful are getting harder and harder to source. The vendors will find substitutes and for the short term they may buy up all of the old stock they can get their hands on.

[FABombjoy]

I ran Denso IT20 iridium plugs from 2005-2018. I changed to one-step colder after turbocharging. Iridium plugs operate without any trouble, firing reliably even when my turbo rebuilder screwed up the seals & I was consuming lots of oil.

I don't think the PRV itself is as fussy about plugs so much as unneeded mods being installed in tandem causing problems, crappy wires that don't seat correctly, things like that. Avoid gimmick plugs like +4 and use wires with a history of success and you should be good.

[Patrick C]

I ran Denso IT20 iridium plugs from 2005-2018. I changed to one-step colder after turbocharging. Iridium plugs operate without any trouble, firing reliably even when my turbo rebuilder screwed up the seals & I was consuming lots of oil.

I don't think the PRV itself is as fussy about plugs so much as unneeded mods being installed in tandem causing problems, crappy wires that don't seat correctly, things like that. Avoid gimmick plugs like +4 and use wires with a history of success and you should be good.

+1. The quality of Bosch plugs is not what it used to be either. I’m running Autolite XP103 Iridium XPs in VIN 1880 at DPI’s suggestion, and they are great.

[82DMC12]

Most of the newer sparkplugs have that coating on the threads. If you are concerned, apply a tiny dab of copper grease or anti seize grease to the threads, but, just be carful torque them in as grease will cause you to torque it at a higher level.

As for replacement, I'm actually going to try NGK 2238 plugs (should have them in a day or two from Rockauto), they are copper plugs and are cheap and the same ones that DMCH sells. These engines don't really need anything fancy in them.

Thanks for the tip. They are available locally, too, if this the plug you are talking about?
https://shop.advanceautoparts.com/p/ngk-v-power-spark-plug-tr5-2238/19650088-p

[dmcman73]

+1. The quality of Bosch plugs is not what it used to be either. I’m running Autolite XP103 Iridium XPs in VIN 1880 at DPI’s suggestion, and they are great.

What gap are you setting the Autolites to? I have these in the car currently and I'm not too happy with them so far.

[CFI]

I’m also running Autolite XP103 Iridium XP spark plugs.

[82DMC12]

Anyone have any tips for cleaning the spark plug wells before I put my new plugs in? I'm thinking I will thread one of my old plugs in first, scrub the inside of the well with a brush and maybe some WD-40, and then use a vacuum to suck out the junk. The spark plug will keep crap from falling further down. Then remove the spark plug and move on to the next well.

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[Patrick C]

What gap are you setting the Autolites to? I have these in the car currently and I'm not too happy with them so far.

Gapped to .024.

[Chris 16409]

I have been stock piling the Bosch Silver plugs for this very reason. You can sometimes find them listed on eBay. Make a saved search so you can check regularly.

[David T]

When the iridium plugs first came out a few of us were using them. We started noticing the cars developed a miss, it was the plugs leaking at the seal. Went back to the regular plugs and never had a problem. The iridium plugs were developed so you could go 100,000 miles without touching the plugs. Not so important for most of us. Especially with their premium price! On boosted cars you should use a smaller gap. Experiment to find the best one.

[82DMC12]

Well I think I will try the NGK 2238 plugs. Easy to get at Autozone. I picked up a set tonight and checked the service book - it says to gap to .024 - .028. I know the plugs will wear down after many many miles but most of us don't put that kind of mileage on our cars. The Bosch HR6 plugs I pulled out were gapped to around .026. Should I set the NGK's to .026 as well? Right in the middle.

[dmcman73]

Thanks for the tip. They are available locally, too, if this the plug you are talking about?
https://shop.advanceautoparts.com/p/ngk-v-power-spark-plug-tr5-2238/19650088-p

Yes, those are the ones, but, you can get them for like a $1.50 each on Rockauto.

[dmcman73]

When the iridium plugs first came out a few of us were using them. We started noticing the cars developed a miss, it was the plugs leaking at the seal. Went back to the regular plugs and never had a problem. The iridium plugs were developed so you could go 100,000 miles without touching the plugs. Not so important for most of us. Especially with their premium price! On boosted cars you should use a smaller gap. Experiment to find the best one.

Are you talking about the Autolite iridiums? That's similar to what I am seeing as well, sort of a miss/backfire which is why I want to try the plain old NGK 2238's.

[FABombjoy]

When the iridium plugs first came out a few of us were using them. We started noticing the cars developed a miss, it was the plugs leaking at the seal.

Which plugs?
Which seal? The taper seal @ the heads or the weather seal?

There are advantages to iridium beyond wear properties. It sounds like something unrelated to the electrode is the issue.



On boosted cars you should use a smaller gap. Experiment to find the best one.
I'm not sure who the audience is here but I'll turn and address them too:
The IT22 is one-step colder than the IT20, gapped at 0.8mm (vs 1.1mm for the IT20) and works well on my low-boost turbo car. Wires are Magnecor.

[David T]

The ceramic to the outer shell leaked. Like they weren't crimped on properly. Very unusual, never saw that on any other plug. Had to be a manufacturing defect. Usually one out of 6. Very easy to see once you pull the plugs, you can see the residue stain on the ceramic. No one saw any benefits from using them, especially at the price at the time, so we went back to the standard plugs. It's the same the ignition coils, air filters (K & N), and the ignition wires. Some owners bought "performance" parts and either did not see any improvement or worse, the parts fail prematurely.

[dmcman73]

The ceramic to the outer shell leaked. Like they weren't crimped on properly. Very unusual, never saw that on any other plug. Had to be a manufacturing defect. Usually one out of 6. Very easy to see once you pull the plugs, you can see the residue stain on the ceramic. No one saw any benefits from using them, especially at the price at the time, so we went back to the standard plugs. It's the same the ignition coils, air filters (K & N), and the ignition wires. Some owners bought "performance" parts and either did not see any improvement or worse, the parts fail prematurely.

The market is flooded with counterfeit parts, including spark plugs. Depending where they bought their plugs from (like Amazon, eBay, etc), the units with leaking ceramics could have been knock offs and some of the knock offs look like the real thing minus some subtle differences.

[David T]

You're right, it could have been knock-offs but they were bought through reputable distributors. The other possibility is that Bosch started "outsourcing", getting their stuff made in 3rd world countries, and the quality went downhill. In any case they were not worth the premium price. Maybe now they are better? Still, what benefits do Iridium plugs offer besides a longer service interval which is irrelevant to most of us.

[DL4567]

dmcman73, did you install the NGK 2238s? How do you like them?
I'm trying to figure out which ones to buy for my car, or even whether to replace them all all. I'm in the valley for another reason, and figured I'd do plugs, wires, distributor cap and rotor, and fuel lines while I'm in there. (all new experiences for me -- I'm no expert).

[82DMC12]

dmcman73, did you install the NGK 2238s? How do you like them?
I'm trying to figure out which ones to buy for my car, or even whether to replace them all all. I'm in the valley for another reason, and figured I'd do plugs, wires, distributor cap and rotor, and fuel lines while I'm in there. (all new experiences for me -- I'm no expert).

You're probably actually asking me, not dmcman73 since I started the thread. Yes I installed the NGK 2238's, I gapped them right in the middle of the recommended range, and put a dab of antiseize on the threads with a brush before installing. I probably only put 50 miles on them before starting a new project where the car is laid up for a while but they seemed to work just fine. Based on that and other's experience I'd say they are a good buy.

[DL4567]

You're probably actually asking me, not dmcman73 since I started the thread. Yes I installed the NGK 2238's, I gapped them right in the middle of the recommended range, and put a dab of antiseize on the threads with a brush before installing. I probably only put 50 miles on them before starting a new project where the car is laid up for a while but they seemed to work just fine. Based on that and other's experience I'd say they are a good buy.

Thanks! I've never changed spark plugs before on any engine, so trying to figure out if it's even necessary at this point. To my knowledge, they were fresh 14,000 miles / 21 years ago. (28k-42k miles)

[82DMC12]

Thanks! I've never changed spark plugs before on any engine, so trying to figure out if it's even necessary at this point. To my knowledge, they were fresh 14,000 miles / 21 years ago. (28k-42k miles)

Well if they have been in there for over 20 years I'd definitely recommend pulling them out. You don't want them to seize up in the engine. Plus, checking your plugs tells you a lot about the health of your engine. You should probably get the engine nice and hot and pull them out while the engine is still hot to the touch. If you try to take them out cold you might find them hard to remove (even worse, break one off). Maybe put a couple drops of marvel mystery oil into the plug wells a couple days prior first to help yourself out.

[Mark D]

You should probably get the engine nice and hot and pull them out while the engine is still hot to the touch.

Pulling spark plugs from an aluminum head when it's still hot can increase the likelihood of stripping the threads out of the head. Warm is OK, but everything I've read says not to pull plugs when the engine is still hot.

Seems to be true for installation as well in terms of stripping threads. A hot engine can also affect the residual torque value on the plugs.

[DL4567]

If I pull them, it's going to be stone cold, as I've had the intake manifold and all other necessary parts off the engine for some time.