fuel filter question with diesel purge

[ready-ronnie]

I have diesel purge and both fuel filters and Ive read all the threads, but I don't know if I should change the filters before or after I use the diesel purge??? Thanks for any help

Originally posted by ready-ronnie
I have diesel purge and both fuel filters and Ive read all the threads, but I don't know if I should change the filters before or after I use the diesel purge??? Thanks for any help

It would be recommended to do a DP first (to clean the injectors and any dirt will be captured by the old filters) and replaced the Pre and Main fuel filters after.

[P.E.Haiges]

Ready,

I wouldn't replace either of the filters if they didn't display any indication of a restriction in the fuel flow.

P E H

[rdanz]

Originally posted by P.E.Haiges
Ready,

I wouldn't replace either of the filters if they didn't display any indication of a restriction in the fuel flow.

P E H

How would they display a restriction? and how often should they be changed?

Mercedes fuel filters are scheduled to be replaced every 30kmi, but I have found that with a little care on my part to buy fuel from reliable vendors, modern fuel delivery methods provides fuel of sufficient quality to often allow the filters to last MUCH longer. I have several that are fine after 60-80kmi. I do eliminate any water in the fuel several times a year with fuel anti-freeze or anti-gel, so any residual water trapped by the filter is sequestered and consumed.

Signs of fuel filter contamination is usually a restriction to full flow. This only occurs when the engine is fully loaded and you are at relatively high rpm (4000+). A quick check is to measure the acceleration from 0-62 mph (0-100 km/h) and when it creaps up a second or two, it's probably time. When the weather gets cold, if you've not been diligent about filling in winterized fuel, as the fuel starts to cloud (that's at about freezing) a slightly occluded filter will allow the wax particals to restrict flow and power will be restricted (the engine will usually start and idle okay). A slightly restricted filter will paradoxically often result in INCREASED fuel consumption. If you are driving largely in the city (where maximum power is seldom required) this increased fuel consumption may be the first signs of a clogged filter.

Just ONE load of "bad" fuel however, and you may need to change filters even if you put in new ones YESTERDAY! Use only OEM filters (Mann, Hengst, Knecht, Bosch are all OEM for Mercedes fuel filters).

Marshall

It takes about $10.00 and 30 minutes to replace the fuel filters. A very reasonable maintenance cost to ensure clean fuel entering the fuel system. I change mine 3 to 4 times per year (evry season change) and use Howes diesel conditioner in the tank each fill-up. The cars run smooth!

My $0.02

[DieselAddict]

I believe it's better to change the filters before doing Diesel Purge otherwise the DP may clean out the dirty filters too and bring some of the junk through your injectors. Plus new filters will ensure unobstructed flow of the DP for better cleaning of the injectors.

[SW]

FWIW, I once ran DP (method where DP is the fuel tank) and the inline filter sort of melted.

If Diesel Purge melted the in-line filter, then it WASN'T an OE filter. I've used Diesel Purge with all the OE brands and it's NEVER melted anything!

Marshall

Originally posted by SW
FWIW, I once ran DP (method where DP is the fuel tank) and the inline filter sort of melted.

I don't think you're suppose to light it up! LOL!!!

But if you didn't, that is unusual as it had never happened to me. I keep plenty of spares at $1.50 each, it's worth having one or two in the garage.

[Judge]

You asked, How would they display a restriction? and how often should they be changed?

I haven't had a diesel long enough to really know, but the first of the two filters is made of clear plastic. My idea was when I see the clear filter becoming cloudy or dirty I ought to replace it.

I also thought I'd replace the first $2.00 clear filter more often then I would replace the second $10.00 screw on filter.

[P.E.Haiges]

Judge,

The filters "display a restriction" when the cars feels like it is driving into a head wind when going up a hill. Up until that time, the filters do not need replacement no matter how they look.

If the fuel filter in the fuel tamk is becoming restricted, it will "display being restricted" by acting like it is almost out of fuel, but actually not, when the fuel level in the tank is low and OK when the tank has more than 1/4 full.

P E H

[WANT '71 280SEL]

How often for the in-line filter?
Thanks
David