Fuel Filter Replacement Time Frame

I am pretty sure that I read on here that the fuel filter on our cars are supposed to be replaced/changed every 20k miles. I feel like this is a bit excessive. I just bought a new WIX fuel filter for $30 since I have 20k miles since the last time I changed it. After buying it I think my current filter still have plenty of life left. The last time I changed my fuel filter I cut it open and it still looked great after having somewhere from 25-30k miles on the old filter. I may wait to change mine until I get to 30-40k unless someone can explain something that I dont know or dont understand.


It doesnt really make much sense to go by mileage instead of gallons of fuel ran thought the filter. Take our cars that get 40-50 mpg VS some of the diesel pickup trucks such as Chevy, Ford, Dodge that gets much lower fuel economy. They are going to run a lot more fuel through their filters in the same 20k miles. I do understand that they "designed" the system on our cars ect ect but I think they can go a bit longer.


Any insight would be helpful.

It's your car. Why trust the engineers that designed it and it's likely you won't believe anyone here that doesn't tell you to wait until 200k? Just put the filter in a plastic bag and put it in the trunk. Wait until it starts acting up and change it along the road in the dark and snow.

No reason to be harsh, was just looking for some view points.

Fuel quality in North America is uneven at best. I filled my Wagon at the Des Plaines Oasis on Saturday night and noticed the pump was running pretty slow. That's usually a sign of poor pump maintenance. Our fuel filters need to catch what the pump doesn't.

So you may run many more than 20K miles with no issues. But one bad tank of fuel can kill the filter. And several not-so-great tanks can accelerate its demise. I'd prefer to run reliably with 20K changes than chance it with a longer interval.

I open the drain cocks every fall to see if there's any water in the bottom if the fuel filters. Have never found more than a couple of drops. I carry a new filter in the trunk, and have had occasion to use it twice to rescue another tdi owner with a frozen fuel filter.

This fall I decided to change filters in both cars because it had been a while. On checking my records I found the wagon had 50K miles on the filter and the sedan 65K. Both looked like new inside when I cut them open.

Not saying it's good practice to change fuel filters that infrequently, but you can get away with it if you don't happen to get a bad fill.

Simon

unless you let your car idle for MONTHS on end, go by miles.
Normal idle is about 0.08 to 0.11 GPH (gallons per hour)
where as driving on average takes about 8-12 GPH
Going up a mountain pass WOT usually yields 29-31 GPH where as going downhill, defuels the engine down to somewhere at 0.05.
Most normal drivers go 600 miles to a take, some more, some less, as im sure you can imagine. Would it make sense to you to count the hours of use on the engine or the miles?
most equipment counts the hours based on RPM, like tractors, etc...

Just change your fuel filter as per owners manual. something like 15,000 miles.
Or as most do here, every time you change your air filter, or just every 2nd or 4th oil change.

mohawk69 said:

It's your car. Why trust the engineers that designed it and it's likely you won't believe anyone here that doesn't tell you to wait until 200k? Just put the filter in a plastic bag and put it in the trunk. Wait until it starts acting up and change it along the road in the dark and snow.

Click to expand...

The engineers designed it for fuel that was much dirtier at the time. With as clean as the new fuel is, I routinely go 50K before changing mine, and even then it's because I feel guilty, not because the car runs any different.

Just turn it inside out like you would with socks.

Thank you everyone for the responses. This is exactly what I was looking for, different answers with their reasoning behind their choices.

Ol'Rattler said:

Just turn it inside out like you would with socks.

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WHY am i the only person on the face of the earth who i talk to that wears at least 2 pairs of socks each day. I CANT STAND dirty socks in the slightest.

typical VW owners i guess!
dam hippies!

You have to wear shoes too so your socks don't get so dirty so fast.

Mongler98 said:

Normal idle is about 0.08 to 0.11 GPH (gallons per hour)
where as driving on average takes about 8-12 GPH
Going up a mountain pass WOT usually yields 29-31 GPH where as going downhill, defuels the engine down to somewhere at 0.05.

Click to expand...

Normal, flat driving is 1-2 GPH. (60mpg @ 60mph for 1 hour = 1 gal; 40mpg @ 80mph = 2 gal)
Your mountain pass estimate is ludicrous.

Idle sounds about right, if a hair low. If you're relying on Vagcom for idle figures, don't. You can vary that "result" widely, just by changing IQ. The lower the IQ (i.e. higher fuel quantity), the lower your reported "idle GPH". The higher the IQ (lower fuel qty), the higher your "idle GPH".

The only way to get a hard, accurate number for idle GPH would be to bypass the fuel tank, loop both fuel lines into a plastic bottle for 15-30 min, and measure the total fuel used on a gram scale.

turbodieseldyke said:

Normal, flat driving is 1-2 GPH. (60mpg @ 60mph for 1 hour = 1 gal; 40mpg @ 80mph = 2 gal)
Your mountain pass estimate is ludicrous.
Idle sounds about right, if a hair low. If you're relying on Vagcom for idle figures, don't. You can vary that "result" widely, just by changing IQ. The lower the IQ (i.e. higher fuel quantity), the lower your reported "idle GPH". The higher the IQ (lower fuel qty), the higher your "idle GPH".
The only way to get a hard, accurate number for idle GPH would be to bypass the fuel tank, loop both fuel lines into a plastic bottle for 15-30 min, and measure the total fuel used on a gram scale.

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yeaaaa, no, i have logs of 4 seperate TDI's
Im started with scangauge II, but ended up logging with VCDS in the end and plotting in excel.

29 up a mountain is near WOT, on a stock 10mm IP but modded injectors. Im not sure if stock injection makes a difference, im not 100% on that but my guess is that it does not make that much of a difference for flow.

Granted, all these logs were on modified cars, all of them has STOCK fuel pumps but had various injectors from 764's to 502's
Fuel tune from malone did not change the much on the GPH. i would say that they all were +/- 10% of each other though.

This is all just logs and has no real life meaning testing save for one time 3 years ago we had a power outage, I filled the take to the top by cans, and let it ldle and ran a 2000 watt inverter to run a few house outlets and what not. we ran out mini fridge and a few other things, 1800 Watts, worth of power for about 75 some hours. i filled up at the station back to the same level after foam settled int he tank to 7.1 gallons. This is about 0.10 give or take. at idle so thats my only time when the math checked out.
I do know that all the IP's on these cars were hammer moded to about the same 1.4 to 1.8 so maybe thats throwing off my data.

Using the 8-12gph figure for normal driving, you'd empty your tank in 2 hours. Uphill WOT at 30gph, you'd empty it in 30 minutes. I'll leave it to you, to decide if those numbers sound right.

mohawk69 said:

It's your car. Why trust the engineers that designed it and it's likely you won't believe anyone here that doesn't tell you to wait until 200k? Just put the filter in a plastic bag and put it in the trunk. Wait until it starts acting up and change it along the road in the dark and snow.

Click to expand...

Yup, that was an ******* thing to say. Best stay off the board if you're not going to be helpful.

Camel413 said:

I am pretty sure that I read on here that the fuel filter on our cars are supposed to be replaced/changed every 20k miles. I feel like this is a bit excessive. I just bought a new WIX fuel filter for $30 since I have 20k miles since the last time I changed it. After buying it I think my current filter still have plenty of life left. The last time I changed my fuel filter I cut it open and it still looked great after having somewhere from 25-30k miles on the old filter. I may wait to change mine until I get to 30-40k unless someone can explain something that I dont know or dont understand.


It doesnt really make much sense to go by mileage instead of gallons of fuel ran thought the filter. Take our cars that get 40-50 mpg VS some of the diesel pickup trucks such as Chevy, Ford, Dodge that gets much lower fuel economy. They are going to run a lot more fuel through their filters in the same 20k miles. I do understand that they "designed" the system on our cars ect ect but I think they can go a bit longer.


Any insight would be helpful.

Click to expand...

The only real way to evaluate filter condition is with a fuel pressure gauge. IF you're like me, and don't feel a gauge is a necessity, stick with 50K

Dieselfiend said:

Yup, that was an ******* thing to say. Best stay off the board if you're not going to be helpful.

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No, it wasn't. It gets old when someone paid a lot of highly trained engineers to determine replacement timeframes. Instead, why not ask someone you don't know about something they know nothing about. From oil to fuel quality to everything else ad infinitum. Certainly, I agree with some who note little danger in stetching things based on personal experiences you've encountered or experience from others you trust. So there you go. Please remove yourself from the board before you say something else really stupid. Of course, share your oil related expertise before you leave.