Hey all,

A previous owner fitted my 2004 4.6L V8 with a K&N 5046E6 generic clamp on air filter, cutting a hole in the air box to accommodate and then discarding the air box cover so this filter is the receiving 100% of the air intake where it sits. With a new air box costing around $300-$500, I'm curious what more experienced owners and mechanics think about continuing to run this filter or if a new air box is advised.

For context, I'm shaking down some O2 related codes (replacing all four, since I do not know when this was last done), and am now getting the occasional P1174. Before I start chasing a MAF code, I'd like to make sure this isn't a contributing factor. I'd assume the engine is being starved of air?

Photo attached for reference. Again, this is as-is; I just opened the hood and took the photo.

Any [constructive] advise is appreciated.

 

K&N filters are stupid and that thing looks like it needs major cleaning.

 

If you need a new airbox, a junkyard may be your best bet. They are easy to remove and should be in okay condition assuming it wasn't in a front end collision.

 

I think you can find plenty of them on ebay for around $100

 

Agreed that one is very dirty. would clean it up and remove the remnants of the original air box and see how it goes. Clean the MAF if the prior owner put too much oil on the filter it could foul the MAF. I have used them for 10 years on two trucks. I like the way they sound and it leaves much more room to work on the truck with out the airbox. Plus its one screw to remove to filter and you have better access to the belts, PS, etc. Just makes it much easier to diagnose and see what is going on. As far as pulling in "hot" air, there have been various post and sure it may be slightly warmer air, but not enough to matter on these trucks. Looks like the whole engine bay could use some attention. I cant really see, but it looks like you could do a better job routing air to the MAF than what you have shown in the picture. I would clean it up, the MAF and see where it takes you. No need to buy anything at this point.
If you do go back to OEM, make sure what you buy has intact clips. They tend to break.

 

Thanks for your helpful advise, Redrover. I wasn't going to bother cleaning and recharging the filter if it were advised to revert to an OEM filter and box. You are correct when you say the entire engine bay could use a cleaning. It's on the list before swapping O2 sensors out.

 

Redrover, when you removed the air box from your two trucks, did you add some support for your aftermarket air filter? The filter seems to sag the entire MAF intake and I could see it very easily over stressing the sensor wires. The P.O. of my Disco left the box in place as support.

 

If you shop for a used one the 4.6 airbox is different than the 4.0 and usually more $$$$. Easy mistake to make when shopping.

 

It's true. Some of the comments above had me second guessing myself. But no, they're not readily available on eBay. Part no. PHB000300G.
Currently there is only one box, no lid and with one missing latch, for a 4.6 listed in the US. They're asking $101.
There is only one used lid and it's $250.
A new lid is $340.
The whole assembly, new, ranges from $350-$560.

Given it's the 20 year old plastic on these vehicles that's falling apart, it really doesn't make sense to buy used. I'd sooner buy a donor vehicle. So I'm going to clean and run the K&N until I hear a good argument to do otherwise. I'm not fording any rivers. I drive a lot of dirt roads and haul a work trailer on occasion but mostly it's a pavement princess.

 

I used silicon intake tube from ebay an elbow and a small straight piece for the maf. I can't find a photo. But I put an old car wash sponge under the filter just to keep it from banging around.