# Hex cap on spark plugs? **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** rav4, toyota\ **Created:** [December 13, 2023, 10:52am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002 "2023-12-13T10:52:31Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [December 13, 2023, 11:20pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/21 "2023-12-13T23:20:55Z")
For the 2013 2wd version, presuming USA , I only see one engine option L4-2.5L 2AR-FE ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [December 13, 2023, 11:26pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/22 "2023-12-13T23:26:48Z")
> [@George\_San\_Jose1](#): > > For the 2013 2wd version, presuming USA , I only see one engine option > > L4-2.5L 2AR-FE Read all the way to the end of post 10… lol It will explain my post (20) and Nevada’s post (12) a little more… ---
**Author:** ![Small-steps](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@Small-steps](https://community.cartalk.com/u/Small-steps)\ **Post date:** [December 14, 2023, 2:39am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/23 "2023-12-14T02:39:46Z")
The spark plug socket is 16m with the rubber grommet inside, I’ve used it before to change out spark plugs many times. The engine is a 2.0L 3ZR petrol. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [December 14, 2023, 2:58am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/24 "2023-12-14T02:58:29Z")
From the information I have, the 3ZR engine uses the smaller spark plugs; 14 mm socket. ---
**Author:** ![Small-steps](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@Small-steps](https://community.cartalk.com/u/Small-steps)\ **Post date:** [December 14, 2023, 3:18am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/25 "2023-12-14T03:18:18Z")
Ok I’ll have to check what plugs the car actually takes, but what about that hex cap on top of the plug? ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [December 14, 2023, 3:39am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/26 "2023-12-14T03:39:08Z")
$5 says that’s the rubber insert from the too big socket. Fish it out. I have found many uses for a long forceps. Gas line clamp, retrieving keys between the seats, fishing out something caught in the garbage disposal, small engine carb overhaul, etc. ---
**Author:** ![jdmere](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/jdmere/32/3002_2.png) [@jdmere](https://community.cartalk.com/u/jdmere)\ **Post date:** [December 14, 2023, 5:56am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/27 "2023-12-14T05:56:45Z")
Since the best route is going to be to replace the plugs anyway, why not try your socket wrench on one of the new plugs to see if sizing is the problem. That would also enable you to compare the replacement plugs with what you are seeing that is already installed. ---
**Author:** ![Small-steps](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@Small-steps](https://community.cartalk.com/u/Small-steps)\ **Post date:** [December 14, 2023, 6:29am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/28 "2023-12-14T06:29:40Z")
The rubber grommet is still in the socket. So it’s not missing. At this stage I only want to remove the current plugs to see if they’re iridium. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [December 14, 2023, 6:37am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/29 "2023-12-14T06:37:28Z")
The owner’s manual online shows Denso SK20HR11 spark plugs, iridium. The Denso site indicates these spark plugs have a 16 mm hex. What does your owner’s manual show? ---
**Author:** ![Small-steps](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@Small-steps](https://community.cartalk.com/u/Small-steps)\ **Post date:** [December 14, 2023, 8:24am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/30 "2023-12-14T08:24:05Z")
The owner’s manual says Denso SC20HR11. So I’m using the correct socket. ---
**Author:** ![Small-steps](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@Small-steps](https://community.cartalk.com/u/Small-steps)\ **Post date:** [December 14, 2023, 8:31am UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/31 "2023-12-14T08:31:25Z")
Actually the Denso website says its a 14m bolt head, so I’ll need to get a 14m spark plug socket. It also says the plug is iridium and the only place where the cars been serviced before is Toyota and they would have put in the correct plugs in. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [December 14, 2023, 9:31pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/32 "2023-12-14T21:31:43Z")
> [@Small-steps](#): > > what about that hex cap on top of the plug? I’m not seeing a hex cap on top of the plug in your photo on post 1. Does anybody else here see it? Suggest to show a better view, better focus, or use a photo editor to add an outline to the first photo showing where you are seeing the hex cap. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [December 14, 2023, 9:50pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/33 "2023-12-14T21:50:32Z")
I don’t see it either. Just looked like a chunk of rubber. Can’t see how a coil could shoot a spark through that to the plug. Seems to me first thing would be fishing it out to see what it was. As Dave I think said, has had coils come apart before and hard to get the remains out. Naturally the socket, whether 14 or 16 will not do much with that chunk of rubber down there. At some point niece will be asking what is taking so long on her car for a one hour plug job. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [December 14, 2023, 9:59pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/34 "2023-12-14T21:59:21Z")
> [@bing](#): > > Can’t see how a coil could shoot a spark through that to the plug. It can’t. Ask me how I know? … lol …However OP says the rubber plug remains in the socket, so I think what we are seeing in that photo is just the top of the spark plug, but slightly un-foccused. OP might compare to the replacement spark plugs. The socket must be rotating around the plug b/c it is the wrong size. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [December 14, 2023, 10:05pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/35 "2023-12-14T22:05:41Z")
In the picture below, the red dot is on the coil connection, green dot on the porcelain and blue dots are on the base/hex. ![image](https://global.discourse-cdn.com/cartalk/original/3X/b/b/bbc7bad8a9b66dcd19f113e4524f4ff544d7cec5.jpeg) ---
**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\ **Post date:** [December 14, 2023, 10:06pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/36 "2023-12-14T22:06:28Z")
I didn’t see anything either. My new guess is that they’re actually 14mm on the hex. (I also looked on the Denso site and found 14mm, tho @Nevada_545 said he saw 16mm (which I assumed from the start, but we know why we don’t assume). ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [December 14, 2023, 10:07pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/37 "2023-12-14T22:07:59Z")
So it’s a wild goose chase and just using too big a socket? I don’t even change plugs on the lawn mower before taking a new one and matching it to the right socket. More to come. Reset the gap and let the electrode break off and ruin the engine. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [December 14, 2023, 10:09pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/38 "2023-12-14T22:09:39Z")
OP says its a “petrol” engine, so presuming OP is not in USA, and the plugs are differently sized there for the make/model/year. OP is not able to compare old to new plugs b/c the old plug is nearly impossible to see, being down inside that hole. ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [December 14, 2023, 10:17pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/39 "2023-12-14T22:17:33Z")
> [@George\_San\_Jose1](#): > > OP says its a “petrol” engine, so presuming OP is not in USA Really George??? I made a post already about this… > [@davesmopar](#): > > > [@George\_San\_Jose1](#): > > > > For the 2013 2wd version, presuming USA , I only see one engine option > > > > L4-2.5L 2AR-FE > > Read all the way to the end of post 10… lol > It will explain my post (20) and Nevada’s post (12) a little more… Here is POST #10 that I asked you to read… > [@Small-steps](#): > > Ok I’ll check coil 4 and see if it’s the same. > I’ll have do it tomorrow morning as it’s 10 past midnight here in Western Australia. Just incase you missed it again… 🤦‍♂️ # Western Australia. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [December 14, 2023, 10:22pm UTC](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002/40 "2023-12-14T22:22:23Z")
This is a SC20HR11 at a different angle, same as the spark plug in the original post, no rubber boot. ![image](https://global.discourse-cdn.com/cartalk/original/3X/8/3/831e0e907fc068b692ab3e43e950f2876a7d6c34.jpeg) [Previous page](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002.md?page=1) [Next page](https://community.cartalk.com/t/hex-cap-on-spark-plugs/194002.md?page=3)