diesel filter on 170 tdi

**a8 tech** · 16-03-2011,01:38 PM

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DSG4ME · 16-03-2011,01:54 PM

Be careful with the alloy pipes on the filter lid, try not to stress them, they are a weak point and a new filter house is £180.

**toddy2008** · 19-03-2011,01:38 PM

hi all
just got round to taking a sample from the filter housing and it don't look to good, i have put an atttachment with this post so you can see what i mean, hopefully the attachment has worked, all opinions are welcome
thanks again
colin

**Crasher** · 19-03-2011,03:12 PM

That must have some engine oil in the tank.

**toddy2008** · 19-03-2011,03:21 PM

any ideas how that could happen, i know i've not put any in, i bought car with a failed oil pump/balance shaft which i sorted, dont think this could cause this though,

**Crasher** · 19-03-2011,03:30 PM

Tandem pump, quite common.

**toddy2008** · 19-03-2011,05:12 PM

thanks crasher
once i change the pump should i leave the old filter in until i have used up and refilled the tank a few times to flush out the oil that may be in the tank and then put new filter in
.thanks again
colin

**toddy2008** · 19-03-2011,05:50 PM

just had one other thought
if oil is mixing with the diesel via the tandem pump is it possible that there is diesel in the oil,
i will do a oil and filter change anyway to be on the safe side.

also i'd like to thank everyone who has given me any advice on this over the last few days

thanks
colin

**a8 tech** · 19-03-2011,06:06 PM

yes change the oil and filter after these steps

drain the tank via tripping the fuel pump fuse until the tank is empty then remove the pressure pump and clean the tank by hand and clean the pressure pump (if the pump looks like its heavily blocked by oil then flush it or replace it)

fit a new sender/pressure pump tank o ring seal and refit

add 5 litres of petrol but ideally a flushing agent, disconnect the fuel filter pipe and trip the fuel pump fuse again and flush till empty

clean out the fuel filter housing fit new filter and then fit the new tandem pump and fill the tank with 10 litres of diesel

trip the pressure pump fuse again until fuel reaches the tandem pump and start the engine

brim the tank and check for leaks around the fuel tank o ring seal

just a note for future reference when evaluating the sample

Soot will show streaks and particles and will begin to separate after two hours or more.

Oil will be uniform in colour throughout the sample. No streaks or particles will be present and no separation will occur.

**Crasher** · 19-03-2011,06:09 PM

I base my decision on how bad it appears to be, one was so heavily contaminated that I had a look inside the tank (quite easy to do) and decided to fit a new lift pump as it was filthy. After interrogating the owner it turned out he usually ran the car quite low, only putting about £20 into and empty tank each time so that sort of explained why it was so thick with oil. I would clean out the fuel filter pot, fit a new filter and pump and fill the tank to the top The question is these days, “which will cost more, filing the tank or the tandem pump?”