Air Filter for Focust 2.3 liter motor

I've always been pretty biased towards K&N filters, when using cleanable air filters. However there is new evidence to show that this type of filter is actually harmful to newer engines. I'm a classic car guy, I like my cars old. I've always seen impressive gains in horsepower and torque when using a K&N filter according to the directions.

The engine air filter on every car can be changed. The air box on this car is secured with 3 or 4 clips. Open the clips by pushing/pulling them away from the air box and lift the air box cover to access the filter.

You can check to see if the filter needs to be replaced by tapping it on the ground lightly and seeing if any dirt/dust falls off. If so, look through the folds of the filter towards the sun. If you can see light, the filter still has light in it.

I've always told car owners to use this test as a gauge on whether they need a new filter and ignore the manufacturers service intervals. Sure, it cost me a little money in filter sales, but it made me much more in loyal customers. I would NEVER go beyond 20K to 30K miles with an air filter, though.

As for filter reliability, when using standard paper filters, I've never run into any issues. I have typically recommended Fram and now recommend the Air Hog variety if it is available for your engine. Other mechanics like Purolater, though.

As for the Amsoil, I'm not a fan. I prefer Kendall GT in my bigger engines and Castrol Syntec or Full Synthetic in my smaller engines. No matter what oil you go with, I'd never recommend going any farther than 10K miles on a single oil change, unless you have an extra large pan and/or extra filtration. ESPECIALLY with a 4 cylinder engine. Especially with half of your driving being city type(harsh conditions per OEM specs). Brand/weight and type is a toss up. You'll find guys that say "yeah, switch to Amsoil" and you'll find others that will say " go ahead, but it's your engine being ruined." 6 of one, half a dozen of the other.

THANKS FOR YOUR REPLY !!
(1.)2004 Ford Focus, 4 cylinder, 2.3 Liter Engine, I may have to look further because I really cannot find any clips or etc. to change the air filter under the hood - it baffles me because I know exactly what it should look like (standard air hose going to filter box, but I cannot see it anywhere) Any further direction would be appreciated?

I found post like this online

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“Q&A: How do i open the air box to clean my air filter on a 2004 ford focus 2.3l?”
1. Mike m says:
May 9, 2011 at 12:35 pm
It should just have a few clips that hold on, you just push them off. Or it might have some screws.

Reply
2. fordgirl2079 says:
May 9, 2011 at 1:09 pm
This is going to sound stupid, but on this particular car, with this particular engine, the air filter is NOT SERVICEABLE. Any attempt to remove air filter for service WILL result in needing to replace the entire airbox assembly at a cost of $297.56US through fordparts.com. Apparently these filters are NOT to be serviced before 100,000 miles (160,000 kilometers) as per Ford Motor Company. Again, this is only on Focuses equipped with the 2.3L Duratec engine, not the 2.0L SPI engine, or the the 2.0L DOHC Zetec engine.

Reply
3. ETHOL says:
May 9, 2011 at 1:58 pm
Fordgirl is absolutely right on this. & Yes it DOES sound stupid…(te he)

But here is documentation to back her statements up:
see the #1 footnote on page 209 of this (free, downloadable) copy of your owners manual for 2004 Ford Focus:


note:
please take advantage of saving the owners manual to your computer for future reference…..but when choosing the ‘Best Answer’, that really should go to Fordgirl
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(2.)Just curiously wondering on your opinion - I want to get away from doing a oil change so often since I drive so much! Does the Castrol Synthetic allow for going to 5K with this engine type, if I want to keep this motor going into 150+ miles. Any recommendations other that Castrol and how long for going on oil change with the recommended oil.

If it matters this car seems to have had Valvoline 5w-20 ran in it so far.

Castrol says you should change its Syntec and Synthetics around 8-10K miles. If most of your driving was non-traffic freeway, I'd say you could stretch synthetics to 15k, but you drive 50-50, city/highway, so, with a full synthetic, I'd play it safe and change at a max of 10k. Considering the price and time it takes, it's better to err on the side of safety and not run the risk of hurting the engine.

As for the air filter, I'm not having any luck finding any other information. I found the same thread you did and one of the replies there said the air box is riveted shut. Theoretically, you can drill the rivets and then use machine screws and nuts to re-close it.

I never believe manufacturer's wild claims about 100K mile anything. The car is a 97, so it's beyond the manufacturer's warranty. Whenever I've seen a car where the owner believed the mileage claims made by the maker, they ended up sorry. I'd never go beyond a max of 30K on an air filter. I'm guessing that you can find the air box where the filter is. Find the rivets and drill them out after you've bought a few small machine screws and nuts. A clean air filter delivers better performance and allows the PZEV to stay practically zero.

I accidently put in 1997 for as the article title - old car I have.

This car is a 2004 Ford Focus ZTS, 2.3 Liter. I am still having trouble finding the air filter box. (please read the previous post in this thread)

Does anyone know of a website where to find images or written direct instruction to show you how to access the air filter on this engine?

Find the intake manifold. Then find the big tube coming out of it. Follow that big tube to the air box. From the sounds of it, it may be difficult to find and even harder to access.

From the pictures I can find, the air box should be located (looking at the engine from the front of the car looking rearward) on the right hand side of the engine compartment.

Here's a link to the owner's manual:
http://www.focusplanet.com/downloads/focusmanuals/2004/2004_focus_owner_guidemanual.pdf

Page 168 shows the location of the air box. It's under and in front of the battery box. The service interval recommendations I've found say the filter should be replaced at 30K intervals. However, page 207 of the manual calls it a "lifetime" item.

Thank you for the reply and helpful advice!! I always come to 2carpros because I have had great luck with the answers being correct and not just some unknowledgeable opinion. Thanks again.

This may or may not do anything for you, I have no clue what engine it is....Imma Jeep CJ kinda Guy, and I also mess with old Fords too.....Old in my book!

It sounds as if this is "Fresh Air Cabin Filter" changin'--but if you'll continue to watch, this feller changes the "combustion air filter too......I did not search long, you might try different searches and come up with more.

http://www.youtube.com/watch?v=f4nCtwFeego

I hope it does a little something for you.

rivermikerat--1st time I've seen you on here, I admire the depth you go to assist someone (a lot of guys, sling out short technical answers, leaving the questioneer, lost-er than he was!)...I try to do the same, I am mostly limited to Older Jeeps and Fords, or problems common to all vehicles....I'm not a professional mechanic, I do it out of necessity for me and mine...I am learning some of the new stuff to keep up with the wife's 'need' to own a newer something, I reckon to keep up w/ the Jones'!!!

Welcome aboard!.....From the Hillbilly Controversial Guy, at 2carfellers....I may come get you, if I get in over my head, on a post! (with your permission)

The Medic

Hey CJ. Been here for a few. Seen a number of your answers and been impressed. I was raised in the old school of doing business: Rule #1: The customer is always right. Rule #2: If the customer is wrong, refer to Rule #1.

I've seen some of those "huh?" answers myself and it makes me mad. If you feel the need, come get me.

Roger!

You do need a unique avatar, so you can be spotted quickly!

Thanks,

The Medic