So whats the go Pinocchio....should I fit a secondary filter/water separator BEFORE or AFTER the primary filter?? Some say before some say after.
Thanks for all and any help.
Personally after for me, as IF it gets blocked it can cause all sorts of problems on inlet line ie damage fuel pump as it tries to suck the fuel/ loss of prime if you have to crack the inlet line and it can be problem on long runs (obviously depends where fuel pump is).
After the pump it more manageable and you can locate and change easier and bleed easier (hopefully).
No single answer as it can depend on several factors.
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Why is it so? Professor Julius Sumner Miller, a profound influence on my life, who explained science to us on TV in the 60's.
My thoughts are put an extra filter/water separator before the primary one. That is how they were done when diesels commonly had a pair of filters fitted as standard. The first one had a drain to remove the water.
That way the crap gets removed first and the second filter them collects the rest.
My thoughts are put an extra filter/water separator before the primary one. That is how they were done when diesels commonly had a pair of filters fitted as standard. The first one had a drain to remove the water.
That way the crap gets removed first and the second filter them collects the rest.
Jaahn
a good point, agree. I misread the OP agin
-- Edited by Baz421 on Tuesday 5th of May 2015 06:22:56 PM
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Why is it so? Professor Julius Sumner Miller, a profound influence on my life, who explained science to us on TV in the 60's.
Most modern diesels have two pumps, one pumps from the tank through the filter and back to the tank continuously. After the fuel filter there is a tee that feeds the second high pressure fuel pump that pumps the fuel into the common rail to the injectors.
The flow through this area is about what your fuel usage is and some extra that is bleed back into the tank or fuel return line.
So in my ford ranger I have a 2 micron filter in this line and due to the lower fuel flow works very effectively.
Water in modern diesels is a killer due to the high fuel pressures and pump / injector tolerances.
If I get water into the system the secondary filter will block rather than let this through plus shed it into the drainage bowl at the bottom of the filter. The injector pump may not like this but should do less damage than water or rust going through the system.
I have worked on diesels for years and some of that time in third world countries where the fuel distribution is poor. Drums and rain. In the old days the water was a usual problem and there were water seperators as standard on most vehicles. Of course with water comes the rust and dirt too. No diesel likes this stuff, old ones or the new ones. The pumps wear out or seize, nozzles holes clog, so things have not really changed there.
What has changed IMHO is the manufacturers have stopped putting the extra insurance of good filters on. My older Toyota has a filter with a water drain on the bottom and a warning light for draining needed. How hard is that ? How much does that cost ? Almost zilch
So I stand by my suggestion of a prefilter, if necessary the filter can be a bit coarser to reduce restriction and the second one could be finer to be more effective. When the fuel is circulated from the tank through the filters and back, as has been the design for many years, the filters may pick up a lot more crap but the tank is being cleaned as it does it. Better in the filters than the pump Whatever is in the tank will come into the system some time least wanted usually.
Jaahn
-- Edited by Jaahn on Wednesday 6th of May 2015 09:19:13 AM
-- Edited by Jaahn on Wednesday 6th of May 2015 09:28:31 AM
I agree with the comments here, but be careful if your vehicle is still in its warranty. If the motor craps out and the Dealer blames your 2nd filter, your warranty is voided. Check with your vehicle dealer before fitting anything like this....don't give them a reason for you to have to dip very deeply into your pocket
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Cheers Bruce
The amazing things you see when nomading Australia
I had a D4D Hilux they had a major problem with injectors , I replaced mine twice , When anything went wrong with the fuel system Toyota would just say contaminated fuel and deny warranty so you might as well fit a second filter .
FWIW I spoke to a mechanic who specialises in 4wd diesels and he said he has fitted thousands of secondary filters and always AFTER the primary filter. Not sure what to do now. The ppl who sell the filters say before!!!!
Thanks for the advice and help
-- Edited by Bas + Eve on Friday 8th of May 2015 10:27:57 PM
FWIW I spoke to a mechanic who specialises in 4wd diesels and he said he has fitted thousands of secondary filters and always AFTER the primary filter. Not sure what to do now. The ppl who sell the filters say before!!!!
Thanks for the advice and help
-- Edited by Bas + Eve on Friday 8th of May 2015 10:27:57 PM
Hi Bas + Eve,
I have had my say My suggestion is to look at what is fitted to light trucks and tractors. They are working vehicles and have the extra protection built on to do the job. See what they do !
FWIW I spoke to a mechanic who specialises in 4wd diesels and he said he has fitted thousands of secondary filters and always AFTER the primary filter. Not sure what to do now. The ppl who sell the filters say before!!!!
Thanks for the advice and help
-- Edited by Bas + Eve on Friday 8th of May 2015 10:27:57 PM
Hi Bas + Eve,
I have had my say My suggestion is to look at what is fitted to light trucks and tractors. They are working vehicles and have the extra protection built on to do the job. See what they do !
Jaahn
Well you have the experience mate and there is nothing like experience....so I'll go with what you say. Thank you
