Wix Fuel Filter Cross Reference Guide
WIX fuel filters live in the 33000 number block, and WIX is one of the few brands that publishes a micron rating for every one of them. That rating is nominal, not absolute, which is the detail that explains most of the confusion around fuel filter ratings, including the famous 2 micron claim attached to Caterpillar's 1R-0750.
Cross referencing a WIX fuel filter is easier than most brands because WIX publishes more. Its catalogue gives a micron rating, a thread size, a burst pressure and a maximum flow rate on the same page, and those four numbers settle questions that other charts leave open.
As an Amazon Associate we earn from qualifying purchases.
What WIX Fuel Filter Numbers Mean
Fuel filters sit in the 33000 series. Oil filters use the 51000 and 57000 blocks, so a number starting 33 is a fuel filter before you look anything else up.
The digits are an index rather than a description, exactly as they are on the FRAM fuel filter side. What the number does not tell you is the rating, the thread or the size, which is why the catalogue page matters more than the number.
An NP suffix marks the NanoPro version of the same filter, such as 33528NP alongside 33528. Same fitment, different media.
WIX Publishes a Nominal Micron Rating on Every Fuel Filter
This is the useful part, and it is unusual. Open any WIX fuel filter page and the rating is printed there.
| WIX number | Nominal micron rating | Thread | Typical application |
|---|---|---|---|
| 33528 | 2 micron | 1-14 | Cat engines and equipment |
| 33674 | 2 micron | 1-14 | Cat engines, longer body |
| 33365 | 10 micron | 7/16-20 | Onan engines, primary |
| 33684 | 30 micron | listed by dimensions | John Deere and CLAAS, primary |
All four use what WIX calls enhanced cellulose or cellulose media. The spread from 2 to 30 microns across four fuel filters from one brand is not a quality ladder. It is four different positions in four different fuel systems.
Nominal Is Not Absolute, and That Is the Whole Story
A nominal rating describes the particle size a filter catches most of. An absolute rating describes the size above which essentially nothing gets through. The same physical filter can honestly be called 2 micron nominal and something much coarser in absolute terms, because the two scales are not measuring the same thing.
That single distinction resolves an argument that runs through every diesel forum. WIX publishes 2 micron nominal for the 33528, the filter that crosses to Caterpillar's 1R-0750. Caterpillar's own publication describes its Advanced Efficiency line in absolute terms at 5 to 10 microns, as covered in the Cat fuel filter cross reference.
Those two numbers are not a contradiction. They are two different measurements of the same filter, and almost every page that quotes one of them drops the word that makes it meaningful.
When you compare filters across brands, compare nominal to nominal or absolute to absolute. The fuel filter micron rating guide covers what each scale is actually measuring.
As an Amazon Associate we earn from qualifying purchases.
Two WIX Numbers, One Housing, Different Ratings
WIX's own page for the 33528 points at the 33352 as the 6 micron version. Same job, same family, different rating.
That is the trap worth knowing about on any WIX cross reference. A chart that maps your old filter to a WIX number has matched the fitment, and the rating is a separate decision sitting quietly inside the part number you picked.
Where the position is a coarse primary filter ahead of the pump, the finer number will restrict flow before its time. Where the position is a fine secondary filter, the coarser number passes particles the injection system was never meant to see. Which side of the pump you are on is covered in fuel filter position.
What Else WIX Publishes That Most Brands Do Not
Two numbers on the WIX page are worth reading before you buy any cross-referenced replacement.
Burst pressure. The 33365 is listed at 270 PSI and the 33674 at 419 PSI. That is the pressure class question made concrete, and almost no other brand prints it on a public product page.
Maximum flow rate. The 33365 is listed at 2 GPM while the 33528 and 33674 are listed at 12 to 15 GPM. A filter rated for 2 GPM in a position that needs 12 is a restriction, whatever the micron rating says.
Together those two figures do what a cross reference chart cannot: they tell you whether the replacement can survive the pressure and pass the volume your system actually runs.
As an Amazon Associate we earn from qualifying purchases.
How to Cross Reference a WIX Fuel Filter
- Start from WIX's own catalogue, not an interchange site. The WIX filter lookup takes a vehicle or a competitor part number and returns the WIX equivalent.
- Open the part detail page for whatever it returns and write down the micron rating, thread, height, gasket dimensions, burst pressure and flow rate.
- Compare those against the filter you are removing, not against the part number you were given.
- Check for a sibling number at a different rating, such as the 33528 and 33352 pair, and decide deliberately which one your position needs.
- Treat third-party interchange results as candidates to confirm in the WIX catalogue, for the reasons set out in the fuel filter cross reference guide.
Frequently Asked Questions
What micron is a WIX fuel filter? It depends on the part, and WIX publishes the figure for each one. The 33528 and 33674 are listed at 2 micron nominal, the 33365 at 10 micron nominal and the 33684 at 30 micron nominal. All of those are nominal ratings rather than absolute ones.
What WIX filter replaces the Cat 1R-0750? The 33528 is the WIX number that appears against it in Baldwin's cross reference chart, on a 1-14 inch thread with a 2 micron nominal rating and a 12 to 15 GPM flow rating. Confirm the body length against the filter you are removing, since the 33674 shares the thread and rating but stands considerably taller.
What is the difference between WIX 33528 and 33352? Rating. WIX's own catalogue page for the 33528 lists the 33352 as the 6 micron version of the same filter. The fitment is the point of similarity, and the micron rating is the choice you are making when you pick between them.
What does NP mean on a WIX filter number? NP marks the NanoPro version, such as 33528NP or 33674NP. It shares the base filter's fitment and uses different media, so it is a media upgrade rather than a different part for a different application.
Is WIX 33684 a water separator? Yes. WIX lists it as a fuel water separator at 30 micron nominal on cellulose media, catalogued as a primary filter for John Deere and CLAAS machines. A 30 micron primary is doing a completely different job from a 2 micron secondary filter.
What to Do Next
Write down the micron rating, thread, burst pressure and flow rate of the WIX number a chart hands you, then check all four against the filter you are replacing. WIX is one of the few brands that gives you every one of those figures on a public page, so the cross reference is only as good as your willingness to read them.
