LEAKY PUMA AIR BOX !

[Drover]

Hey guys,

I recently install a Brit-Part snorkel on Puma SVX. When talking to a friend, he suggested that I should put a plastic bag over the snorkel to check for any air leaks.

The theory is that if there are no air leaks then the engine will stall, if air leaks are present then the engine will continue to run.

Guess what – the engine didn’t miss a beat. I wasn’t real impressed with the factory ducting to the air box (seemed to be very narrow in places and with various joins ) so I replaced it with some 65mm ID marine exhaust tubing, glued it up with Sikaflex, beautiful.

Did the bag test - no change, engine kept running no problems.

I have traced the air leak to the air box lid ! It seems that enough air is entering from between the lid and the box, above the air cleaner so unfiltered air can enter the engine.

So, Puma owners, has anybody done this test or know about this issue or know what can be done to fix it.

All comments and opinions are welcome.

Cheers

[spudboy]

I like the logic of that test!!

Not sure if a plastic bag would be strong enough to stall the engine, as I suspect that with a perfect seal the bag would have holes sucked through it, but a good test idea.

Will be watching with interest!

[seano87]

I like the logic of that test!!

Not sure if a plastic bag would be strong enough to stall the engine, as I suspect that with a perfect seal the bag would have holes sucked through it, but a good test idea.

Will be watching with interest!

Just out of curiosity, I tried the plastic bag test over the snorkel of my 300tdi. I have heard of this method of testing before.

The bag was very quickly sucked onto the snorkel and formed a pretty good seal over it. It didn't make the engine stall BUT I'd confidently say mine is all sealed well, the exhaust started to show some carbon being spat out, and the intake air tubing from box to manifold got very well flattened together. No noises from air being sucked in from around the seal of the air box or any joins, I think it still just manages to get enough from around the snorkel head. Whilst it didn't suck holes into the plastic bag, I think if I'd left it a little longer it would have.

Also, mine is a Safari snorkel, and remember that the snorkel head has bits at the base of the head that allow water to flow out for when driving into heavy rain, a plastic bag won't seal that bit too well and hence why the engine probably won't stall.

[Drover]

The plastic bag is sucked hard around the top of the snorkel, with out doubt, but enough air still makes it way into the engine to run it.

The bag is definitely sealing. The ducting to the box is definitely sealing. It can only leave the air box lid ! or a least that is all that I can think of.

[isuzurover]

The plastic bag is sucked hard around the top of the snorkel, with out doubt, but enough air still makes it way into the engine to run it.

The bag is definitely sealing. The ducting to the box is definitely sealing. It can only leave the air box lid ! or a least that is all that I can think of.

As mentioned above - were you doing these experiments with the (ram) snorkel head removed???

If you have some, try putting some vaseline or rubber grease on the air filter seal and see if that does the trick.

[dmdigital]

As mentioned about the ram.

Have you also closed of the drain hole in the bottom of the air filter box?

The airflow is via the base of the air box up through the filter and on to the engine. There's definitely at least one open drain hole and I'm not sure if the air box is a press fit or bolted to the front guard. The air filter box lid and top side of the filter stays incredibly clean I've found. In all honesty I find the amount of dust into the air box is incredibly minor after owning Disco's.

[isuzurover]

Btw - the plastic bag is a bad idea - better to use something solid which cannot be sucked in.

[fraser130]

Have you considered air through the crankcase breather?

Just a thought

[MTB]

Drover did you ever complete your experiment?

If I disconnect the pipe going from the air box to the turbo and place a rubber mat over the end of the hose, whilst the engine is running, in order to seal it, the engine will stall within 5 seconds.

If I place the rubber mat over the top of the snorkle (with the ram head removed) the engine runs quite happily.

I have now completely uninstalled the Safari Snorkel, sealed the duckbill at the bottom of the air box, also sealed the drain plug that is inline in the ducting from the air box to the wing, reinstalled the Snorkel, sikaflexed all the joints (some where originally sealed by ARB, others where not at all !!!).

I waited for the sikaflex to cure and retested - no change, engine still runs happily with the top of the snorkel sealed.

So I have come to the same conclusion as you, the only place where air could now be getting into the system is the lid of the air box.

I came across this photo on the Discovery2 website, maybe that is the answer - add a strip of foam/rubber tape to the lid?

https://www.aulro.com/afvb/images/imported/2011/08/599.jpg

[Drover]

Hey MTB,

No never did solve the probelm or get exactly to the bottom of it.

I like your idea, I think I will give it a go when I get my new snorkel.

Cheers

[isuzurover]

To trace leaks on a diesel intake, you can spray "start ya bastard"/Aerostart or even WD40/RP7 where you suspect the leak is located - while the engine is idling.

If there is a leak the revs will pick up.

The solution may be as simple as coating the seal on the filter element with suitable grease.

Another option, is to grease the seal, and then apply sikaflex to the mating surface(s). This will then form a gasket once dried.

[tuesdayfox]

HI guys,
any updates???

I am about to put a snorkel in my truck and a bit worried....

I Do Not Want a Cosmetic Chimney on my defender.....but it seems the case at this stage....:wasntme:

any body fix the leaky airbox??

[n plus one]

HI guys,
any updates???

I am about to put a snorkel in my truck and a bit worried....

I Do Not Want a Cosmetic Chimney on my defender.....but it seems the case at this stage....:wasntme:

any body fix the leaky airbox??

Look in the Verandah for 'Nugget' - it solves most of these issues. I grease my air box element seal and have never seen any hint of dust or moisture in my air box. The plastic bag 'test' is an extreme one (IMO) that has little relevance to actually driving conditions (hint: try calculating how deep your car needs to be underwater to replicate the pressure differential situation created by the bag test and you'll see what I mean).

[Marty110]

the Nugget gear stops leaks from the snorkel to the airbox but not the lid. when you get a K&N filter for the Puma it states that you need to use 'special' K&N grease on the filter seal with the lid - so maybe, as suggested by others, a bit of grease on the seal, maybe with MTB's foam as well. BTW the airbox to lid seal is a bastard in any case as you have to be very careful when re-fitting the lid - most times it wont seat properly without quite some effort and 'jiggling' - I always check the lid is seated properly several times, the lid tends to distort too - such a poor design after the great filter on the 300Tdi's

[n plus one]

the Nugget gear stops leaks from the snorkel to the airbox but not the lid. when you get a K&N filter for the Puma it states that you need to use 'special' K&N grease on the filter seal with the lid - so maybe, as suggested by others, a bit of grease on the seal, maybe with MTB's foam as well. BTW the airbox to lid seal is a bastard in any case as you have to be very careful when re-fitting the lid - most times it wont seat properly without quite some effort and 'jiggling' - I always check the lid is seated properly several times, the lid tends to distort too - such a poor design after the great filter on the 300Tdi's

Yep, the air box lid is a bit of fun! I spent the last couple of weeks checking mine daily - suffice to say I'm much better at fitting it now!

[DefenderJim]

Yes they do leak. My Puma took a drink a couple of weeks back, still with PCB trying to figure out the extent of the damage :( .. maybe a market for someone more creative than I to make a better aftermarket air box...

Jim

[noogie]

Another issue with the puma airbox is its location at the front of the car. As previously mentioned they don't clamp down hard enough. A mate has a puma and on one trip his car was running a little rough. Had a look under the bonnet and half his air filter was soaked and covered in sludge from bog holes.

Something to think about with the airbox located at the front of the engine bay.

[Drover]

Yes they do leak, maybe a market for someone more creative than I to make a better aftermarket air box...
Jim

Sounds like a job for Nugget !

Please

[newhue]

perhaps a nice little mod for that spanking new 130 that's about to show up.

What do you think Wayne?

[nugge t]

On a very long list Jason but it is something that I WILL do hopefully early in the new year..... at the moment it is just behind a tray, slide on camper and refitting the gear I have taken front the 110.:D