Fuel Filter

I just bought a car with 101k on it, and am having maintainence done (e.g. timing belt, tranny flush, etc). Something that I thought of and the shop did not mention is replacing the fuel filter. It seems sensible to do this, but I don’t hear is mentioned much. What do the assembled masses think?
PS: I do not have any maintainence records for this car.

I would replace it.


Please tell us what this mystery vehicle is . . .

There may be a reason why the shop didn’t recommend a fuel filter replacement

A good example . . .

The vehicle doesn’t even have an external fuel filter

Such is often the case, when the vehicle has a returnless fuel system

Fuel filters should be changed every 15k miles if possible. An engine can run fine on a partially clogged filter but it will stress the fuel pump a lot more and can cause an early pump death. That’s happened twice in my family.

My Lincoln had a clogged filter (10k miles on it) and was changed before a long road trip. I made the comment to my wife several times during the trip of my concerns over the pump. About 25 miles from the house at night in heavy thunderstorms the pump quit right at the end of the trip.

My son’s Lincoln LS had a clogged filter which I changed and warned of the pump. This was in late summer and he lived in Greeley, CO at the time. Not many months later while coming back to OK for Christmas the pump died near Hays, KS; necessitating spending the night in a hotel and waiting for the Ford dealer to get the new pump the next day which happened to be on a Saturday.

1999 Lexus LS 400

Thanks for the information

Rockauto shows a fuel filter . . . the typical older type, with banjo bolts

I’ll assume it’s mounted on the firewall

I’d go ahead and replace it now

You can easily check the condition of the old filter once removed. Dump all of the gasoline out of it and allow it to dry out for a number of hours.
Now blow through the inlet side. With a good filter you should be able to blow through it easily just like a soda straw. If you feel resistance then it’s clogged to some degree.

Is there an arrow to mark the flow direction?
Or maybe the direction doesn’t matter. It isn’t a diode…


The direction does matter


The banjo bolt goes on the side with that “L” on it. The hose end goes through there. Then the banjo bolt and 2 washers, one on each side of the hose

I can’t really explain it very well but I’ll say this . . . you couldn’t hook the hoses up wrong, unless you had popeye arms and were intentionally trying to do harm

A Lexus is a fancy Toyota. My Toyota dealer has long recommended AGAINST changing fuel filters this old on Toyotas if you are not experiencing problems. You will find that the lines going into the filter will disintegrate and your simple fuel filter replacement will become an expensive and time consuming fuel line replacement. I ran a 1995 Previa 10 years to a mileage of 220,000 without ever replacing the fuel filter and my current 2004 Sienna has 196,200 miles with the original fuel filter.

I wouldn’t change it if you have no fuel related symptoms. I’d keep it as is until 150 K.

If you do decide for a change-out, no worries. Make sure you very thoroughly clean the outside of the filter and the hoses and connectors going to the existing filter before undoing them. Use a toothbrush or something and a solvent to get rid of every bit of gunk. Otherwise you risk introducing dirt into the clean side of the fuel system in the process of replacing the filter. I always pour some gasoline into the input side of the new filter and let it drain out the other side and take a close look at what comes out, to make sure there’s no dirt in the new filter too. Suggest to use a special type of wrench called flare wrench for fuel line work. In some cases the access is very limited and you’ll need a crows-foot version of a flare wrench. It’s very important to avoid cross threading during the install, as that may ruin both the new filter and the existing fuel line fittings. I expect you already know this, but all the necessary safety precautions dealing with gasoline must be strictly followed. Do this outside, away from any building, and keep a big fire extinguisher you know with 100% certainty works close by.

My brother has a '01 V6 Camry (100K or so) and recently tried to replace the fuel filter. He could not get one of the connections loose and just returned the filter. It runs fine.

From personal experience, I can confirm that it can be extremely difficult to replace those style filters

A bit of advice . . . do NOT use open end wrenches. You WILL round off the fittings, and you’ll be making it that much more difficult

Use line wrenches, or a crowfoot attachment with an extension and ratchet

But it sounds like OP is paying a shop to replace the filter. So it would be their responsibility. I wonder if they didn’t mention the filter, BECAUSE they know from personal experience what a PITA it sometimes is to replace it

I would replace it unless you know it was already replaced in the last 30,000 miles or so.

Jeff, you have been giving advice to 3 and 5 year old posts. While replies are appreciated, they are better applied to posts from the current year. Look in the upper right hand corner for the month and year of the thread… Aug '15 or August 2015

Welcome to the Forum!

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Good point.