syswei

My car is at the local dealer for periodic maintenance and they want an extra $174 to replace the engine air filter. Sounds rather high so I may DIY, but when I look for "S550 engine air filter" for a 2008, I see two kinds:

1. flat rectangular, like (I believe I would need two)

2. or a truncated cone-shaped filter like
Do I need just a pair of the flat rectangulars, or do I also need the truncated cone? If I need all of them, maybe I'll just let the dealer do it...I don't even know where the truncated cone would go. The service manual says for 52k miles "engine compartment...replace air-cleaner insert".

Thanks in advance for any help.

phatisfy

Go autozone or advance auto parts and get the K&N engine filter. its a lot better than oem!

dannieboiz

per K&N site, we need two of these? Do you really noticed any gains?

http://www.knfilters.com/search/prod...x?Prod=33-2181

marthyh

Yes you need two filtration units, the discussion about oem and K&N or other open filters is an old one.

I have investigated a bit and would recommend 'paper' oem or 'paper' oem-replacement:

as K&N or equivalent need to be oiled and risk of this is that your MAP-sensor gets polluted.(That for me, is the primary reason not to switch over)

Unless you really are making the engine breathe better:headers; exhaust ; intake; porting etc then yes ,you 'd need a foam filter if any..

The air-flow for this standard engine is plenty with the oem-air filter and you would have an unnoticable gain,its only more expensive(altought to me that is secondairy)..

Ok agreed you can re-use the K&N but do you really want to s&^@ around with washing dirty oily air-filters then be carefull not to over-oil etc ?(3rd reason)

Also the filtration level of the paper filter is much better then any foam units so your engine will live a bit longer.(4rd reason)

phatisfy

I have used K&N filters in every car I've owned. And had no issue what so ever. I do feel a slight differance in throttle response. But nothing major.

Quadcammer

well the studies done on this differ from your anecdotal evidence.

The K&Ns flow more when clean because they don't filter as well. When they get dirty, they filter as well as the oem, but don't flow as well. Add in the possibility of damage to the MAF from the filter oil and you end up with zero benefit.

syswei

Thanks for the replies, my question though isn't really what brand to get, but what type/shape. I THINK I need two flat rectangular filters like

...but do I also need a third filter, a truncated cone-shaped filter like ??? ...and where does the third one go?

castro69

Only the two flat rectangular filters.
http://www.ebay.com/itm/MANN-FILTER-...81035173801%26

PelicanParts.com

That cylindrical filter is for aftermarket performance air filter housings.

syswei

I see, thanks!

mymbz

Hello!! I plan to change it myself also, could someone show me how to remove the back piece of engine cover, it has a metal clip in the back, I can't remove it . Thanks

dannieboiz

stick a flat head screw driver in the ring and pop it out. It's spring loaded so don't be afraid. A light push will pop it out.

RA032924

I just replaced my air filters yesterday (07 s550 base model) , and was scared to pull off the engine covers for fear of breaking something.

In fact too scared to stick a screw driver in there, not knowing what to expect. The front piece I just grabbed each side and pulled it off, though I was gentle, not much force was required. For the rear, I felt for each of the clips on the corners, which are on rubber mounts (make sure the engine is cold so you dont burn yourself). Then gently slide them off their mounts by hand one by one. Also, there is a metal hold-down clip at the center of the very back holding down an air inlet into the engine. Just lift slightly and push back, as it will slide off. The air inlet adapter has a rubber seal on it, so you may still feel a but of friction as you pull it off, but just twist as you pull it off and it will come out no problem.

When reinstalling, I did the reverse, feeling for the rubber mounts and re-mounting one at a time. Finally, sliding the clip at the center rear back on until it snaps into place.

Hope this helps.

mymbz

Thank you so much guys for helping, my filters will be here on Wed, hope everything will go well