Ventectomy -- New guy's first mod!

Just did my ventectomy. One thing to be aware of. When removing the retainer clip to get the spring and valve out don't let it fly apart and shoot parts across the garage. You will not find them. I now know.

I finally did it, WOO HOO! I carefully pried the retaining clip and spring out with my fingernails and didn't loose any parts. I put the spring and clip back in. The vent and switch asm would make a cool gear shift knob for a toy car! (aprox 1:20th scale).

To answer my own question: when filling on the "lowest setting" from a regular diesel nozzel I found it shut off around the same time as before, then I had to slowly fill by hand (lowest setting just keeps clicking off). This is just perfect! Its no different from before, no danger of spillage! Only diff is that you don't have to push on the vent. I filled 'till the foam came right up to the top as usual and got EXACTLY 37.4 L just as my ScanGauge reported. Could not be happier! I was so happy that I wasn't even bothered by the fact that I paid the highest price ever: 134.9 canadian cents per liter (US dollars at par that would be $5.10 per gallon!)

I fill til I see foam, let it settle, repeat until clear fuel is up to the lip, go check my oil, then come back and top it off.

creekfreak said:

let it fly apart and shoot parts across the garage.

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let 'er fly ! ! ! !

Is this new? I've never heard of this. You have got to be kidding me. You can't read the plz. reads. Good lord it's been there for at least 5 years. That's where I learned it. Read the how to's please. I know they won't because they have already left. I'm upset. AARRRGGGHHH.

737tdi

Now what do you do with the VENT after its removed?

737tdi said:

Is this new? I've never heard of this. You have got to be kidding me. You can't read the plz. reads. Good lord it's been there for at least 5 years. That's where I learned it. Read the how to's please. I know they won't because they have already left. I'm upset. AARRRGGGHHH.

737tdi

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Maybe these pictures will cheer you up?

Mini Gearshift:


ThinkPad Joystick:


Novelty Pen Holder:


This little thing is so cute... Gotta turn it into a keychain somehow!

Just FYI, the latest entry to the long term test of the VW TDI by Edmunds Inside Line now links to this thread. http://blogs.edmunds.com/roadtests/.eea79cf

I.M.O. that has nothing to do with the ventectomy? My tank has always read full. The mod simply lets you use the expansion portion of the tank. That car or any car should read full from the factory. The ventectomy simply allows you to put more fuel in the tank. It will read full for 100 to 125 miles before dropping. It's not a more fuel mileage thing, it is a more mileage thing. I've only been able to get 868 miles, then I filled up.

Good luck with it:
737tdi

ventectomy is only an aid to obtaining a more accurate FE reading. The other advantage is maximizing your tank range.

I agree with TDITOM and 737TDI,

The person who wrote that article either has a problem with their instrument cluster, or their fuel sending unit. That has nothing to do with venting.

Also, the 2001 GOLF Manual does mention the vent: it says that it is there to provide air expansion space in case fuel expands. It also says that you can vent as long as the vehicle will be driven a fair distance in order to consume enough fuel to leave space for expansion.

Also, the 2001 GOLF Manual says that "when the fuel light comes on you have aprox 7 L in reserve" in my experience I found this to be true.

Also, my fuel gauge has always gone precisely to full without venting. When I do vent i get 9.5L extra (aprox 1.9 gallons) and the fuel gauge goes slightly beyond full and doesn't drop below full until I've driven 100-200km which is the distance it takes to burn off those extra 9.5L.

My conclusion: the 7L reserve after the fuel light comes on is not affected by venting.

NarfBLAST said:

...My conclusion: the 7L reserve after the fuel light comes on is not affected by venting.

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Yeah, the reserve is at the other end of the tank from the vent

tditom said:

Yeah, the reserve is at the other end of the tank from the vent

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LOL! EXACTLY!!!

A big thanks to GWilli! I had performed a similar operation on my Dodge Ram/Cummins...the difference is that you need to run the fuel level low, drop the tank, bore a hole to install a $35. kit. Good old VWs...so much simpler in so many ways. Gotta love em.
I will say that the white plastic was very stubborn and would not budge till I inserted my brake adjusting tool in the filler neck and pried against it while depressing the tab...presto! Thanks again.

Finally did this on my B4V. I think I got out 2 lbs of dirt and earth(?) out from around the fill neck. Nasty stuff.

Filling up this morning was a lot easier without having to keep the vent tab pushed in. Probably halved my filling time.

NarfBLAST said:

My conclusion: the 7L reserve after the fuel light comes on is not affected by venting.

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Correct. The light is most likely triggered by a particular Ohm reading in the float rheostat, ie, when the float drops to a particular position. 7L will always occupy the same volume---yes, yes, fuel expands when it heats and contracts when it cools, but Diesel doesn't expand enough to worry about it. This is why you can fill to the brim and drive 50 feet and not worry about fuel leaking out the filler on a hot day.

Just finished mine today, the pics were extremely helpful. Next step is either Alligator or RCII and then Sprint 520's. Does anyone have a contact for RCII, I've tried phone and email several times each.

mj1053 said:

Just finished mine today, the pics were extremely helpful. Next step is either Alligator or RCII and then Sprint 520's. Does anyone have a contact for RCII, I've tried phone and email several times each.

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Best way to get in touch with RocketChip is to go to a GTG where Jeff is attending. Second best is email... he eventually answers all emails, just takes him a few weeks because he is so back logged.

Stopped at Sears and bought a set of Torx drivers and excised the offending parts, successfully completing the ventectomy.

Quite easy!

If you can work a screw driver, you can do it.

I put a bit of wd40 on both sides of valve and it slipped right out and back in.

This may not be related to the ventectomy but I have never done it on my golf but planned on doing so until I filled up for the first time. I set the diesel pump at it's slowest speed and let the pump run while I pop the hood and check all the fluids. When the pump automaticaly stops I can only put a max 1 gallon more into the tank before I see a small stream of fuel coming out of a small hose that comes out under the rear corner of the car near the fuel fill area.

Could the previous owner already have done the ventectomy?

If that is not the obvious case why would the fuel be coming out under the car and is it something i should worry about?

kbrenny said:

I see a small stream of fuel coming out of a small hose that comes out under the rear corner of the car near the fuel fill area.

Could the previous owner already have done the ventectomy?

If that is not the obvious case why would the fuel be coming out under the car and is it something i should worry about?

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This does not sound ventectomy related, the ventectomy does not open an holes to the atmosphere, it only opens an internal passage that is normally open only when you put the fuel cap on.

Is that the hose that connects to the small hole below the fuel filler neck? The only way fuel can get in there is if it overflows the filler neck. If you are not overflowing out the top and fuel is getting out of the system some other way then that is cause for concern. There are a bunch of hoses in the vent system, maybe one has come loose? There is a picture in the Bently manual.

looked today while I was filling up and it is coming through the hose that is connected just underneath the filler.

kbrenny said:

looked today while I was filling up and it is coming through the hose that is connected just underneath the filler.

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Just had a look at the Bentley manual and there is nothing connected to that tube. It is just a spillage drain tube. If you are leaking while filling out that hose are you sure you are not spilling slightly?

It is very simple to remove the filler door and rubber housing surrounding the filler neck and it gives you a much better view. Perhaps you have a leak and it is just dripping along this tube and is giving the appearance of coming out the spillage tube.

Polo 9N2 ventectomy

Just did this on my Polo 9N3.
(OOPs Polo hatch is 9N3 not 9N2 - keep forgetting - can an admin please edit the post title?)

Only things to note that don't show up on the ventectomy pics:
1. plastic housing for the fuel filler door has to be compressed a little front to rear for the plastic housing of the flap spring pin to clear the bodywork to remove
2. vent housing is at the front rather than rear, catch is on top and easy to access
3. pressure on the vent button towards the catch while gently releasing the white plastic spring catch (so as not to snap it off) helps eject the vent body - you can also put a finger in the vent body to stop from breaking off the catch.
4. when replacing the housing, the hinge end needed to be pushed in to get it to seat properly with the bodywork.
5. as always when replacing self tapping screws, it is rather important to get them to run freely back in the original grooves otherwise repeated use will strip/cut out the threads (have seen self tapped threads damaged too many times by professionals) - start screws backwards until they drop into original grooves, then start gently making sure the screw proceeds freely, else try again.

As a small modification of procedure I wound the vent button through a couple of winding of the spring and then put it back in. So the vent button sticks out a little and stays straight always. No spare parts to store as they are all back in the car with vent disabled. (Can be easily restored to normal if there might be a need.)

bluey said:

Just did this on my Polo 9N2.

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__. Good to hear that it works on a Polo. Here in North America (where most of the board members are), the smallest models we have are the Jetta/Golf and New Beetle. The procedures are different for Jetta/Golf versus the NB so it's not surprizing that the Polo is a little different again.

__. Why don't you take some photos and post them in a new thread ("Ventectomy for Polo") -- that might help other Polo owners around the world.

I've got a NB and I am trying to do a ventectomy but I can't get the cover off the filler neck. I removed the only torx screw I can find on the bottom left but it stil won't budge. I took the cap off too but that didn't help. What am I missing here?

BTW, yesterday I put 15.2 gallons in my Beetle by holding the vent button open.

Todd

Todhog, look for a white piece of plastic on the left side near the bottom. Using a long flat head screw driver, apply pressure on the tab while simultaneously pushing piece away from the filler neck.

todhog said:

I've got a NB and I am trying to do a ventectomy but I can't get the cover off the filler neck. I removed the only torx screw I can find on the bottom left but it stil won't budge. I took the cap off too but that didn't help. What am I missing here?Todd

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DON'T!!!!! I've seen several NB release mechanisms upgefuchted by removing the surround.

Best way to do a NB. Remove right taillight. Insert short screwdriver to press up the tab underneath. Have a helper push on the vent button. Assembly will slide out.

OK, I looked again and didn't see the white piece of plastic. I think there is a miscommunication, I never got to where I could see the vent. I also think the way in is through the tail light. I read earlier where someone went through the tail light on a Beetle. I'll try that in the morning.

Todd

I have done this on 2 NB.
The door release is held in by a clip, if you look closely you will see it. get a small flat blade screwdriver and pry the clip up. and then push the door release in. Then you can pull the whole cap and tub assy aft and out.
Then follow the normal proceedures.
Be careful installing the door release back in. I took my fingers thru the large hole before the tub assy is totally in the fender and guided the release cable back in its hole and took some small needle nose pliars and pulled it into place and slide the clip back on.