Should Airbox Look Like This?

psywrinz

Member
Joined
Feb 24, 2020
Location
Boise, ID
TDI
2002 ALH Golf 5spd 140k miles
Hey guys, this is my first post and thank you in advance for humoring me and hopefully responding with your input/resolution regarding my newbie-query:

I just replaced the air filter in my '02 golf for the first time without enlisting a mechanic. I used the Mann filter with the pre-filter. After much effort to get the new filter to conform to the innermost edges of the airbox and risking what felt like early onset arthritis in my hands, I could not get the airbox to close all the way. When I close and tighten the screws, there is a gap on the side of the box where the latches connect the top and bottom, through which the filter's pink/orange gasket is visible:



I have it now installed in my engine this way but am worried about the potential for air to enter through that gap and into my engine without filtration, although it looks like maybe the gasket could be forming a seal. Either way, why can't I get the airbox to close all the way?

One last question - I've tampered with the new filter enough, un-seated/re-seated it a few times (prior to driving with it). Knowing this, is the filter still fit for use or have I maybe compromised it?

Thanks again for reading!
 

KrashDH

Veteran Member
Joined
Dec 22, 2013
Location
Washington
TDI
2002 Golf
Hey guys, this is my first post and thank you in advance for humoring me and hopefully responding with your input/resolution regarding my newbie-query:

I just replaced the air filter in my '02 golf for the first time without enlisting a mechanic. I used the Mann filter with the pre-filter. After much effort to get the new filter to conform to the innermost edges of the airbox and risking what felt like early onset arthritis in my hands, I could not get the airbox to close all the way. When I close and tighten the screws, there is a gap on the side of the box where the latches connect the top and bottom, through which the filter's pink/orange gasket is visible:



I have it now installed in my engine this way but am worried about the potential for air to enter through that gap and into my engine without filtration, although it looks like maybe the gasket could be forming a seal. Either way, why can't I get the airbox to close all the way?

One last question - I've tampered with the new filter enough, un-seated/re-seated it a few times (prior to driving with it). Knowing this, is the filter still fit for use or have I maybe compromised it?

Thanks again for reading!

Exactly how my new air filter fit (Mann as well). Had that exact same small gap. As long as it's sealing on the top and bottom interfaces you're good to go.
 

soot1

Veteran Member
Joined
Nov 6, 2009
Location
Houston, TX
TDI
Currently none. Formerly: 2010 VW Jetta TDI 6M, 1993 Dodge Ram W250 Cummins 5M 4WD, 1990 VW Jetta Diesel 5M, 1986 VW Jetta Diesel 5M, 1980 VW Uabbit Diesel 4M. Currently driving 2018 Toyota 4Runner SR5 4WD.
At first, I thought one of the plastic pieces was distorted, but then I blew the image up, and it appears the gap is there intentionally - if you look closer on the magnified image, there are clearly visible spacers that are located between the first and second, and then between the third and fourth "latches". Although I am not sure of its purpose, it appears that VW wanted the gap there. If you are concerned that the orange-colored sealing foam on the filter may not be compressed properly and thus, not sealing, try applying some sort of dark-colored ink to the sealing surfaces of the top plastic part. If it seals properly, you should see the imprint of the sealing edges on the rubber foam of the filter. That way you will know exactly what is going on.
 

psywrinz

Member
Joined
Feb 24, 2020
Location
Boise, ID
TDI
2002 ALH Golf 5spd 140k miles
Krash, thank you so much. Noting you're a vet owner, your feedback goes a long way to restoring my confidence in driving this way.
...I've never been mechanically inclined but am hoping to change that. I just finished the process of correcting a P0671 fault code and that was pretty encouraging.
 

KrashDH

Veteran Member
Joined
Dec 22, 2013
Location
Washington
TDI
2002 Golf
Krash, thank you so much. Noting you're a vet owner, your feedback goes a long way to restoring my confidence in driving this way.
...I've never been mechanically inclined but am hoping to change that. I just finished the process of correcting a P0671 fault code and that was pretty encouraging.
No problem that's what the forum is for!
These are great vehicles that will treat you well as long as you do the same for them.
There are much more wise members than myself though on this site that seem to have dedicated themselves to these cars.
I came from the Cummins diesel truck world and needed a commuter car, and having sort of a diesel hobby in my blood, this was naturally the perfect choice for me.
This forum has provided a lot of insight for myself so I try to give back where I can.
 

psywrinz

Member
Joined
Feb 24, 2020
Location
Boise, ID
TDI
2002 ALH Golf 5spd 140k miles
Soot, thanks so much for your input.
-Yeah, it seems a little counterintuitive maybe to engineer the airbox for the gap to exist?
And I think when I read somewhere on the forum that the filters with the pre-filter can be a difficult fit, I assumed I hadn't installed it properly. When I saw a picture on ebay of a replacement airbox that didn't have a gap, this reinforced my suspicion. But further browsing both revealed that to be a PD airbox I think, while also unearthing a couple images of apparent VE boxes that do have the gap.

Anyway, great idea of testing to see if ink makes an imprint as a means of assuring that there is a seal so I'll attempt something like that. But incidentally do you think that continued opening/closing of the box could compromise the seal in itself? Or is that rhetoric dispersed by filter manufacturers in order to increase sales haha?
 

psywrinz

Member
Joined
Feb 24, 2020
Location
Boise, ID
TDI
2002 ALH Golf 5spd 140k miles
Krash, cool, I never even knew about Cummins engines. Awesome that your knowledge can be applied across multiple makes.
...Thanks again!
 

KrashDH

Veteran Member
Joined
Dec 22, 2013
Location
Washington
TDI
2002 Golf
Anyway, great idea of testing to see if ink makes an imprint as a means of assuring that there is a seal so I'll attempt something like that. But incidentally do you think that continued opening/closing of the box could compromise the seal in itself? Or is that rhetoric dispersed by filter manufacturers in order to increase sales haha?

It's fine handling multiple openings/closings. I mean there's really no reason to check it daily or weekly, or even monthly. Just take note when you changed it and check it every so often up to the end of life of the filter. Or if you have suspicion that it's linked to an issue you're having.



Time/heat/fluids/operating conditions/incorrect installation are what kill seals beyond usefulness prematurely.
 

soot1

Veteran Member
Joined
Nov 6, 2009
Location
Houston, TX
TDI
Currently none. Formerly: 2010 VW Jetta TDI 6M, 1993 Dodge Ram W250 Cummins 5M 4WD, 1990 VW Jetta Diesel 5M, 1986 VW Jetta Diesel 5M, 1980 VW Uabbit Diesel 4M. Currently driving 2018 Toyota 4Runner SR5 4WD.
But incidentally do you think that continued opening/closing of the box could compromise the seal in itself? Or is that rhetoric dispersed by filter manufacturers in order to increase sales haha?
The sealing material on the filter is usually some type of polyurethane foam with closed cells. You can compress and release that seal until the cows come home without harming it, for as long as you don't apply force so high that you crush the material, i.e. as long as you don't pop the closed cells open, at which point dirty air might be pulled thru the now open cells. However, crushing the foam would take much larger force than you can develop with your fingers. I would be a lot more concerned about the age of the filter, as polyurethane degrades over time and either hardens or turns into dust. Neither of those two outcomes will provide good seal.

It just occurred to me there may be one plausible reason for the existence of the gap and the bright color of the seal, and that would be visual indication that the air filter is in the box and that you aren't running your engine without air filter. I was just cleaning my Walther PPS a few days ago, and I now recall the gun barrel has a narrow slot milled at the bottom of the round chamber, which allows the user to see the bottom of the chambered round without the need to pull the slide back. That way, you know by just visually checking the slot whether you are "live" or not. The air filter housing gap may have the exact same purpose.
 

psywrinz

Member
Joined
Feb 24, 2020
Location
Boise, ID
TDI
2002 ALH Golf 5spd 140k miles
It's fine handling multiple openings/closings. I mean there's really no reason to check it daily or weekly, or even monthly. Just take note when you changed it and check it every so often up to the end of life of the filter. Or if you have suspicion that it's linked to an issue you're having.



Time/heat/fluids/operating conditions/incorrect installation are what kill seals beyond usefulness prematurely.

Awesome, gotcha. ...Good to know that some of the stuff I've read about "breaking the seal" is probably hyperbole.
 

psywrinz

Member
Joined
Feb 24, 2020
Location
Boise, ID
TDI
2002 ALH Golf 5spd 140k miles
The sealing material on the filter is usually some type of polyurethane foam with closed cells. You can compress and release that seal until the cows come home without harming it, for as long as you don't apply force so high that you crush the material, i.e. as long as you don't pop the closed cells open, at which point dirty air might be pulled thru the now open cells. However, crushing the foam would take much larger force than you can develop with your fingers. I would be a lot more concerned about the age of the filter, as polyurethane degrades over time and either hardens or turns into dust. Neither of those two outcomes will provide good seal.
It just occurred to me there may be one plausible reason for the existence of the gap and the bright color of the seal, and that would be visual indication that the air filter is in the box and that you aren't running your engine without air filter. I was just cleaning my Walther PPS a few days ago, and I now recall the gun barrel has a narrow slot milled at the bottom of the round chamber, which allows the user to see the bottom of the chambered round without the need to pull the slide back. That way, you know by just visually checking the slot whether you are "live" or not. The air filter housing gap may have the exact same purpose.
Hahaha, thanks for the insight and advice. I'll do my best to avoid operating the car with a filter that has dissolved!

Very interesting, well we do have some evidence, to which you'd be more privy than I, that these German engineers built things with a shared sense of sound reasoning and this makes sense about being able to readily extrapolate something as critical as the presence of a functioning, non-disintegrated air filter or say, that of live ammo!
 

Votblindub

Veteran Member
Joined
Dec 22, 2010
Location
NY
TDI
MK4 Jettas: Sedan & Wagon
Close them, seal them tight and youre fine. Different filters will sit a little different in the airbox, but as long as it's tightly closed you can just enjoy driving.
 

hey_allen

Veteran Member
Joined
Nov 25, 2006
Location
Tacoma, WA
TDI
2000 Jetta TDI
If you're really worried about the filter's performance over time, you could install an air filter restriction gauge like this one on the filter housing, above the filter, next to the MAF.


I've had one on my car for ~18 months (and 15,000 miles), and it's been on the same filter ever since.
I'm barely approaching halfway from the new mark to the replace mark on the gauge.
 

Votblindub

Veteran Member
Joined
Dec 22, 2010
Location
NY
TDI
MK4 Jettas: Sedan & Wagon
If you're really worried about the filter's performance over time, you could install an air filter restriction gauge like this one on the filter housing, above the filter, next to the MAF.


I've had one on my car for ~18 months (and 15,000 miles), and it's been on the same filter ever since.
I'm barely approaching halfway from the new mark to the replace mark on the gauge.
I think it's something i'd use if i lived in an area where there's a lot of sand, dirt and dust or loads of vegetation that's just loose and gets vacuumed up into the intake all the time. You probably won't see that thing move much, but I'm curious to find out what it will show at the end of the filter life.
 

hey_allen

Veteran Member
Joined
Nov 25, 2006
Location
Tacoma, WA
TDI
2000 Jetta TDI
... I'm curious to find out what it will show at the end of the filter life.
I'm planning to run it until it says replace, and see how many miles it lasted.

I doubt that there is significant restriction on the rated mileage interval, this the restriction gauge.
 
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