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Fuel/Water Separators for dummies


Jeff.Sloan

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So I don't fully understand the different versions of fuel water separators out there. Mine is not transparent and hangs down from the passenger frame rail, like this:

fws.jpg

 

However I often see photos of clear ones that seem to mount at the bottom and have a glass dome on top. What is the difference between these two types? How does one know that the clear type is full or needs to be replaced? How does one know that my not transparent type is full and needs to be replaced?

 

Should I change to the clear type? Getting an oil change next week the the shop said the service price will vary "depending on the number of filters I need replaced". Is the FWS a filter that get's changed every 25k when the oil is changed?

 

Thanks for bestowing you wisdom on this subject :-)

post-8344-0-88525300-1484202112_thumb.jpg

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That is a 30 micron Filter. You should have another filter on the drivers side also labeled FF____.
On my 2005 ISX I have a Davco 382 fuel/water separator unit running a 10 micron filter. The Davco is probably what you are referring to as the one with the "clear" housing. As the filter gets "dirty" the fuel level moves up on the filter until it reaches the black band at about the 80% mark indicating time to change. The filter bowl is clear so you can see the filter and know when's it's time for a change. My fuel filter (second filter) is a model FF2200 which is a 15 micron filter and is a metal encased unit similar to the one you have and is located low on the drivers side of the engine I put about 15k on my truck each year and change each filter yearly. Both are fairly easy to change. I have had good service from FleetGuard products and use their filters on my truck. An updated oil filter is also available LF14000NN it replaces the LF9080.

 

Here is some info on the Davco.....

http://www.davco.com/FP382.htm

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Thanks. I do have the FF2200 mounted top the engine on the left side. OK sounds like I should have both of those replaced when the oil is done next week. For knowledge's sake, how would I know if either of them were full/clogged? What are the symptoms I should watch out for?

 

Appreciate it

Jeff

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Thanks. I do have the FF2200 mounted top the engine on the left side. OK sounds like I should have both of those replaced when the oil is done next week. For knowledge's sake, how would I know if either of them were full/clogged? What are the symptoms I should watch out for?

 

Appreciate it

Jeff

Decreased performance......Sluggishness......Message on DID for low fuel pressure.

You might want to pick up a couple of spares and learn how to change them out.

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Your primary fuel filter pictured is actually manufactured by Parker/Racor. Here is the current version and their explanation of how it works.

 

http://ph.parker.com/us/17583/en/diesel-fuel-filter-spin-on

 

I have the same primary on my Freightliner with a series 60. And then I have a secondary filter which has a smaller micron rating like MrSeas mentioned above. In the 1.7 million miles I have had my truck my practice is to change both filters at oil change time, about every 15,000 miles. the Racor, or in my case Alliance(freightliner brand) primary filters are about $25 and the secondary which I usually get from Detroit Diesel are about $7. Prices can vary widely. But it is cheap insurance. The partially clear bowl at the bottom did tip me off to an asphaltine problem I developed this summer.

Easy to change, do one at a time, should prevent losing prime. Fill with clean fuel before you reinstall. I ALWAYS carry a spare of each never know when you are going to get a bad load of fuel.

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Asphaltenes are an interesting problem. To answer your question I used this product:

 

http://penray.com/products/total-diesel-fuel-system-cleaner/

 

Penray is a well known additive manufacturer, this was the only one that specifically labeled for asphaltene problems. I bought a case of 12 quarts, put one quart in each 110 gallon tank at a fill, about double the recommended dosage. After about 6 tanks the problem seemed to be gone. The symptom that triggered the dosing was the fact that my fuel filters normally easily make it 15,000 miles between changes. It got to the point I was changing them at 10,000 mile intervals or less. And in the bottom of the clear plastic fuel separator bowl were black "flakes" that would dissolve between your fingers.

 

Asphaltenes have always been in diesel fuel, indeed always have been a problem for the refining industry. 3 changes have caused them to emerge down stream.

1. Ultra low sulfur diesel fuel. Refiners used to just avoid "sour crude", high in sulfur content. When they were required by the EPA to invest billions in sulfur removal technology, they began using lower and lower quality crude stocks. The removal of the sulfur also removed the solvents that would keep the asphaltenes in suspension.

2. Use of Bio Diesel. Bio Diesel has the capability to absorb lots of water and keep it in suspension. For chemical reasons I don't understand, this is part of the equation.

3. Higher temperatures in fuel tanks. Asphaltenes tend to accumulate after tank temps get above a certain number, if memory serves 120+ deg F. With recirculation in the summer, that number is easily exceeded.

Apparently these 3 conditions together cause the problem, a fairly recent one because the first 2 developments are less than 10 years old. For a long time the culprit was thought to be algae, but biocides would be added with no effect. The physical characteristics are different, although operational symptoms are similar. I guess you could have both problems at the same time.

I am going to watch for a problem next summer, at the first hint I am going to start dumping in the Penray. I buy all of my fuel at TA/Petro, but anyone in the industry will tell you all the tankers line up at the farm with no particular difference between them except the advertising.

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Thanks Jeff ... lots of good info

Asphaltine is a known problem in the Cummins ISX due to the warmer return fuel along with summer temps and Bio.
That's why I run a 10 micron filter element in my Davco to catch as much of it as I can before reaching the primary 15 micron filter.
So far seems to be helping stem the flow. I'll pick up some of the Penray to have on hand and also use it as a preventative measure.

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Jeff,

 

Thanks for the explanation. I've not knowingly had the problem, but it might explain why my filter was full on my ISX recently, after only 10,000 miles.

 

So, do those of you running newer trucks have different filters, as in a lower micron rating? I find on farm equipment, the newer pieces have 2 micron filters, with a 10 micron pre-filter. I run a 5 micron on my shuttle tank as a precaution.

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Why would this be an issue on some brands of truck engines and not others? It should appear on all engines, given that all return pretty warm fuel. I suppose that some could have better filters but the issue would exist equally in all tanks unless the fuel was cooled. Right??

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There are so many variables, quality of the crudes the diesel comes from, how much bio diesel your engine is exposed to and of course temperatures. That is why the problem was so hard to identify in the first place, and still not very widely understood in the trucking industry. The brand of engine is one of the more predictable variables, but there is just no consistency to who gets affected and who doesn't.

 

In the HDT application asphaltene accumulation would be less likely. One of the ways to up the temp of the fuel is to use a lot of it, therefore returning lots of hot fuel to the tanks. That would mean pulling heavy loads over challenging terrain for a long time. I mean 70-80k weights, high ambient temps(90+F) high speeds and or mountain grades where fuel mileage would be in 6-7 mpg range trip after trip.

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The HPI and EUI fuel systems return a whole lot of hot fuel. You'd always have a fuel cooler on the truck and you'd have to think really really hard about removing a tank on the truck's second life. Life was also pretty simple and you'd slap a FS1000 on the rail and if you wanted to know what was going on in it you'd order a fuel restriction gauge in the dash. It was pretty easy to top 130 deg in WA and you'd never ever run under 1/4 tank or you'd be in for a set of injectors. Everything caused a new set of injectors. This used to be the stuff we'd worry and argue about before EGR's and DPF's. ;)

 

All the commonrails nowadays don't return much. You need filter heat or a return blender so you don't freeze up in the winter, only need a cooler if one tank, and they don't even squirt return fuel on the tank skin anymore. They've changed quite a bit. Regardless, if you can get fuel temp on your Silverleaf it would be a good thing to watch for both Jeff's reasons and your own fuel economy. Then again, on new trucks EPA gave you have a MIL light for that... ^_^

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