Quote:
Originally Posted by Diesel911
How often to change the Fuel Filters is dependant on the quality of the Fuel you get from the Pump and your willingness and/or skill at changing a Filter on the Road Side.
We have all read stories on this Forum of someone on an out-of-Town trip filling up with some bad Fuel and having the performance effected or even rendered un-drivable.
I buy 98% of my Diesel Fuel from the same Station sinc 1992 and seldom drive more than 20 miles from home. I have never had a Filter plug up on me and effect my performance.
The longest I have driven with the same Fuel filter on my Volvo Diesel for as long as 5 years with no ill effects.
It has only 1 Fuel Filter; but the Filter does have a Drain on it and during the 5 years I drained in one time that I can remember.
But, previously I had changed it ounce a year or ounce every 2 years but not because it was plugged up; just preventative maint.
I do not carry extra Filters in either of my Diesel Cars.
So Fuel Quality and willingness to deal with a Road Side Filter change will be the "Tail Wagging the Dog" so-to-speak.
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As the filter becomes restrictive in service at some point the injection pump base pressure is going to start to fall. Far before any effect is noticeable to the driver the injection base pressure may have sagged well below the better operational pressure area. This condition might be present for months or years possibly.
I have suspected this possibility for a long time. In fact ever since some posters mentioned they had changed their secondary fuel filter and noticed increased fuel milage as an result.
If they changed the filter as part of preventative maintenance with no other noticeable effect present to indicate the need. Then the operational; pressure has obviously increased with the new filter.
Without a pressure gauge installed there is generally speaking no way to know when some restriction is growing in the supply system or the lift pump is gettting too weak to allow overflow from the injection pump. For the money a gauge costs and the small time required to install it.
The time perhaps has come to really consider it as a bellweather or monitor of the condition of the fuel supply. Far better than being stranded on the side of the highway someday.
Besides the lower fuel milage. The possibility of better balancing and sequential timing of the engine being present. If my speculation is also correct about the damage done to the first cylinder over time with the low pressure deficiency it is a really worthwhile addition to these 616 and 617 engines.
Once enough of these are installed troubleshooting the fuel system may decline as a need. Or become so much easier. The gauge should warn you of events well ahead of time in a lot of cases. If it even saved a few engines over the years from disaster it might be worthwile. On a 616 four cylider engine you really should know your operational fuel pressure. At least until low pressure is eliminated or established as the true cause of the number one cylinders excess loading and resultant excessive wearing rod bearings.
I know that I am still flogging a dead horse so to speak. Over time I have observed nothing to reduce the advisability of having a fuel pressure gauge installed. The pressure in the base of any injection pump on these older indirect diesels should be known.
Not the atitude taken that the car does not run too bad or pretty fair so I will ignore it. It is just wrong to expect thirty year old automotive systems to still be as they were new. Of course some will be but there is no sure way to know yours is without a test.