That is the fill plug.

 

Yes. A 10" pair of pliers will grab it. It's a confined space. It's enough room to reach your pliers down and pull it out and and push it in. You can see some fluid on the end of it (if it's full) to give you a rough idea of the condition of the fluid. Not my favorite design. I prefer a dip stick for automatic transmissions. But, at least you don't have to pump it through the check plug on the side of the case from underneath the vehicle. I had to buy a special funnel to fill it. I serviced mine for the first time at 24,700 miles. It was dark brown. My friend has a civic with over 100,000 miles and never changed his. I'm curious to see how long his car lasts with the kind of abuse he puts it through and no preventative maintenance.

 

Thank you!

 

So I've got some bad news.

I decided to visit my mechanic and make sure the CVT fill plug was still in place before a road trip and he confirmed it came off again!!

Since I haven't been checking it, we have no idea when it came off the second time..

He said this has happened to two other customers of his, both with Honda CVTs so it was his opinion that there MUST be a TSB out there about this.

I've contacted the dealer to see if there's an updated part or a TSB, but I have my doubts.

 

So I've got some bad news.

I decided to visit my mechanic and make sure the CVT fill plug was still in place before a road trip and he confirmed it came off again!!

Since I haven't been checking it, we have no idea when it came off the second time..

He said this has happened to two other customers of his, both with Honda CVTs so it was his opinion that there MUST be a TSB out there about this.

I've contacted the dealer to see if there's an updated part or a TSB, but I have my doubts.

Why is so grase that plug? my is clean and dry.

 

I just came across a thread of someone with a civic and the same issue

He bought a new CVT fill plug, which has the same part number as the one required for the HRV - 25615-5T0-004

He wrote : "The replacement plug was .75 of a mm larger in diameter according to my calipers."

Source: ATF filler cap came off. Has this happened to anyone else? - Honda-Tech - Honda Forum Discussion

 

Latest update on the saga:
-Dealer confirmed that there's no TSB on this issue and that the fill plug part number has always remained the same

-I found another thread about this issue which found a solution (link below). They wrote that the fill plug pops out of place because there's a breather vent that's clogged. I'll have my mechanic check it out next week and will update y'all to confirm if it is indeed clogged or not.

Thread with a solution: Honda CVT Fill Plug

The cap for the breather vent is part# 4 in this diagram (21396-P20-000):
https://www.hondapartsnow.com/parts...r_lx_awd-ka_cvt/transmission_automatic/at_torque_converter_case_components.html

Here's what a clogged breather vent looks like (from searching online - not my car) :

 

Where under the hood is the breather?

 

Lo and behold, the cap for the breather vent was completely clogged (photo attached).

I feel bad for everyone who has this happen after 100,000km or so and has no idea it could eventually result in transmission failure.

my mechanic was busy today so I couldn’t ask him to show me where the breather vent is located. I’m seeing him again next Thursday so I will ask him then.

 

Lo and behold, the cap for the breather vent was completely clogged (photo attached).

I feel bad for everyone who has this happen after 100,000km or so and has no idea it could eventually result in transmission failure.

View attachment 30360

my mechanic was busy today so I couldn’t ask him to show me where the breather vent is located. I’m seeing him again next Thursday so I will ask him then.

Thanks for the info. Please try to post a photo of the breather location when you find it.

 

$16.42 was for the rubber fill cap

Breather cap was $7.61

(Canadian dollars)

You're 100% right that the cap can be cleaned but I wasn't sure if it would be missing once it was located so I had bought it.

 

I found the breather cap on mine and it was completely clogged. The hole is tiny so it's not very hard to do. I blew it out with compressed air and put it back on. I'm going to begin checking with every engine oil change from now on.

 

I found the breather cap on mine and it was completely clogged. The whole is tiny so it's not very hard to do. I blew it out with compressed air and out it back on. I'm going to begin checking it everytime I do an oil change from now on.

Where under the hood is it?

 

And it is easy to get off, a little trickery to get back on!

 

Might be a good idea to check rear diff., breather cap on a AWD too when changing rear diff., fuild.
Have seen them plug on trucks.

 

Might be a good idea to check rear diff., breather cap on a AWD too when changing rear diff., fuild.
Have seen them plug on trucks.

the rear diff vents into a breather box

 

I checked the CVT transmission vent on our HRV earlier this week. It was also dirty.

Thanks to everyone who posted info on this thread.

 

Need a bit of help.. even with all the pics I can't find that breather cap (COVID brain fog confirmed?). Using this picture of the engine bay, can someone circle approximately where that breather cap is located?

 

AMIGO right under the thermostat a littlt tricky is 4" to tke left of Filler thansmit. plug beneath the upper coolant hose CONNECTION..

 

not gonna see it with this pic.....look while standing beside the wheel well, and lean over the battery -it's atop of the transmission itself.

 

as viewed in this pic- the engine is "behind" this assmebly, and the transmission would be in "front".
The breather is on top between the two, and closer to the front of the car (nearer the radiator than the firewall)

 

SanPablo's post #24 in this thread with the pictures should allow everyone to find the HRV CVT trans vent plug.

Pull off the air intake tube if you are still have trouble finding it.
Once you have found it, you will be able to remove and re-install it easily just by feel without removing the air intake tube.
Soak the rubber vent in a mild solvent for a few minutes to clean it quickly and completely.


As an aside, a few months ago I discovered that the 6 speed manual trans in our 2006 Acura TSX has exactly same rubber vent cap. I have never noticed it nor cleaned it before but it was spotless.

Then I had a peek at the parts catalog for the 6 speed manual trans in an HRV.
Sure enough, the HRV manual trans has exactly the same rubber vent cap.
The manual trans folks should be checking and cleaning their trans vent cap also.

BTW, the trans vent caps have all the same p/n. 21396-P20-000
HRV CVT, HRV manual trans, 2006 TSX manual trans, Civic CVT plus likely many more.

 

Edit: Found the vent plug. Thanks for all the help!

For those seemingly challenged like myself, the valve cap is (from the Driver's perspective inside the cabin), is 45° to the front and right of the fill plug (the one with the hook). With the placement and position of the various tubes of this HRV, it is entirely obscured by view from above, either standing at the tire wheel or in front of the car. To locate it, stand in front of the car, look directly downwards and look for the bolt facing the starboard wheel circled red. The vent plug is just to the rear of that bolt, on the same elevation. Remove and replace by feel alone.

As for my vent plug, it was relatively clean. This company HRV is at 28,000km, driven entirely between farms. Enjoyed a blast of concentrated farm fertilizer smell cleaning the vent plug.

The vent plug is oriented to face the front however. Honda even marks it with a an arrow and "F" inscribed. This begs the question. Why?
Why would the vent plug be oriented to face forwards? Would not this only introduce ram air foreign debris into the transmission case?

 

I hate to resurrect a sleeping thread but have a couple reasons.

First one is a big THANK YOU to all above.

Second, I just bought a used 2016 HRV with 51k mi. on it after putting 175k on various Subaru's and a CRV (2004). 30 mins here and I am paranoid I have made a terrible mistake WRT CVT equipped model... Wow.

Checked mine and sure enough CVT vent clogged. Vent bore though is spotless. Filler cap top, OTOH, has the same looking crud as in pic, making me wonder if this thing has been spitting fluid from last owner. It was on and tight. I do know tranny service was done at 40k, so maybe just paranoia.

Observations
1. Once past 8/80 belt warrantee this CVT is getting a proper vent. Until then I can clean weekly as I normally check dipstick.
2. Fill plug cavity had no fluid I could see, there is a baffle close underneath and just some yellow drops atop it. There really IS no way to do this right than use overflow to check. Can't even vacuum out old fluid from above.
3. Is everyone sure the 'F' on that vent arrow isn't for FILLER or FILL, instead of front. Is FRONT documented somewhere? It is ludicrous to point that opening at the radiator fan...
4. With zero way to know how long this has been plugged with crud (and how much made it through into the CVT before it plugged), I now need a fluid change and probably filters soon too.

Appreciate all the good advice and help here.

 

I have a question, if you don't mind. Was there a strong odor coming from the driver's side when you stepped out of the car?
The odor is why I had a mechanic look at it. All he found was the transmission fluid cap was off. Of course they weren't able to duplicate the odor issue.

The dealer drained the transmission fluid almost three months ago. This dealer service department has made two inexcusable mistakes with my car. Seems like this is the third. I won't be going back except to complain.

After reading your post, I'm going to have this mechanic drain the fluid and make sure the caps aren't clogged.

 

I have a question, if you don't mind. Was there a strong odor coming from the driver's side when you stepped out of the car?
The odor is why I had a mechanic look at it. All he found was the transmission fluid cap was off. Of course they weren't able to duplicate the odor issue.

The dealer drained the transmission fluid almost three months ago. This dealer service department has made two inexcusable mistakes with my car. Seems like this is the third. I won't be going back except to complain.

After reading your post, I'm going to have this mechanic drain the fluid and make sure the caps aren't clogged.

No strong odors at that time. I DO have one now when the car warms up - but that is my fault. I didn't clean up some of that sulphrous Valvoline CVT fluid I used, that clung to the transmission after overflowing the check hole.

On the topic of dealer maintenance, my vehicle was only ever maintained by the local dealer. Darn near 5 QTS of CVT fluid came out during the drain. I know because I poured and measured twice, I was that surprised. An even 4 QTS filled it per the procedure. Nothing but surprises (upside and downside) with this vehicle.

 

Does anyone know if vent plug was modified in 2018? The TSB dated September 2019, only mentions 2016-2018 year models. https://static.nhtsa.gov/odi/tsbs/2019/MC-10165374-0001.pdf

 

Does anyone know if vent plug was modified in 2018?

The Honda part numbers are the same on 2017 & 2020 listings, if that helps. (Of course, the # could have been updated.)

21396-P20-000 $4.26 each at HondaPartsDeals.com

 

It is mentioned several times above that the breather cap can be removed by feel without removing any parts.

Could someone please advise if I should be reaching in to get the cap on/off from the blue arrow side or the red arrow side?
The red arrow side seems a bit tighter and is at a worse angle I think.
Is putting it back on just as easy? I hate to pull it off and can't get it back on.

 

I had to go out to the garage to confirm!

The small rubber CVT trans vent is directly under the 2 radiator hoses coming from the thermostat housing.
Using my right hand fingers, I can pop off the trans vent going from blue arrow side of your picture.
It is awkward but not hard. I have big hands and long fingers so that could be a factor.
Putting it on is actually easier IMO.

If you still can't get it, the air intake pipe from the rad support to the air intake box is easily removed.
2 push pins on the rad support.

The lower intake air resonator is removed on our HRV but that is not a factor.
It's the black plastic assembly below and forward of the rad hoses.

I hope this helps. It is important to regularly check and clean that CVT trans vent cap.

 

I had to go out to the garage to confirm!

The small rubber CVT trans vent is directly under the 2 radiator hoses coming from the thermostat housing.
Using my right hand fingers, I can pop off the trans vent going from blue arrow side of your picture.
It is awkward but not hard. I have big hands and long fingers so that could be a factor.
Putting it on is actually easier IMO.

If you still can't get it, the air intake pipe from the rad support to the air intake box is easily removed.
2 push pins on the rad support.

The lower intake air resonator is removed on our HRV but that is not a factor.
It's the black plastic assembly below and forward of the rad hoses.

I hope this helps. It is important to regularly check and clean that CVT trans vent cap.

Thanks so much for confirming.
I can feel the rubber vent piece while putting my left hand underneath the lower rad hose from the blue arrow side. There doesn't seem to be much height to pull it straight up and off. I guess it's just rubber so it can be bent/twisted to get it off/on.

May I ask why your air intake resonator is removed from your HRV?

 

On my 2022 HRV the vent plug is a lot different and smaller

 

It looks about the same as my 2016.

 

226k now, I've changed it twice, 1st at 105k second about 180, it keeps popping the oil fill plug, im not sure why.

Have you cleaned out the vent cap???that is a separate piece...If it is clean I would just replace the plug with a new one...they are under 10 dollars...

 

My 2018 HRV has not popped its CVT plug yet, but it is not as tight a fit as I desire. Just a friction fit and well oiled.

In the old Honda days they'd have an updated part very quickly. These days, Honda may never get around to it.

 

226k now, I've changed it twice, 1st at 105k second about 180, it keeps popping the oil fill plug, im not sure why.

i have this issue now too- did an oil change Sunday, and the plug was out- i put it back in checked the vent ( all clean) and it popped off 2 days later.
I checked it this AM and it was good..... did some " internet research" - Civic owners have the same issues.

One guy says his just got loose so he bought another plug and its noticeably tighter, and his issue went away. My new plug will be delivered tomorrow so i can compare.
The current one i really cleaned off the rubber part BUT it does seem slightly looser than when new.
Maybe its just a wear and tear issue with the heat and the fluids compromising the rubber part ?

and found this on line too : From Honda
Check the vent !

 

i have this issue now too- did an oil change Sunday, and the plug was out- i put it back in checked the vent ( all clean) and it popped off 2 days later.
I checked it this AM and it was good..... did some " internet research" - Civic owners have the same issues.

One guy says his just got loose so he bought another plug and its noticeably tighter, and his issue went away. My new plug will be delivered tomorrow so i can compare.
The current one i really cleaned off the rubber part BUT it does seem slightly looser than when new.
Maybe its just a wear and tear issue with the heat and the fluids compromising the rubber part ?

and found this on line too : From Honda
Check the vent !

Strange... I would recommend tethering your current fill plug until you figure out what is going on.
Tie a string or wire to the handle of it so if it pops out, you don't lose it.

As you stated it could be just the rubber plug has shrunk and hardened with heat and age and you just need a new one.

I wonder if one could install a better breather vent on the trans? Rubber hose extended up with a larger vent on the end of the hose?

 

every 2 yrs ( not religiously) replacement for my unit of Feb2016 , the overflow bolt never removed by Honda service center ( seal paint still intact) , they just drain and fill in all the content of the CVT oil container , maybe it is overfilled now . oil leak around the fill plug , had to spray Degreaser and blow with compressed air to remove grime . CVT still ok

noelmem5