Change diesel filter on 151 Leon without airlock

gk5000

Hello,
Was going to DIY maintain the car now that its out of warranty.

Is there a problem with airlocks if I replace the fuel filter on a 151 Leon 1.6 TDI?
I saw a video online where you just fill up the canister on the new filter. Is that enough ? or is there a bleed screw somewhere?
Also, are generic filters ok?

Thanks.

scannerd

most cars have a bleed process, which involves activating the low pressure pump(s), via a scantool or sometimes turning the key a few times will do it. Putting fuel in the new filter is belt & braces but doesn't hurt

FR85

Have a look at the filter housing, on the mkll Leon and Altea there were two different filter housings used, one was a manual bleeder with a small hex head screw in the center of the top between the send /return lines, the other just had the 4 send/return lines. You need to know which you have prior to buying the bits as there are two different filters. If you have the bleed screw you need the filter with the big hole down through the middle along with a small blue grommet that has five rings and a main seal. If you don't have a bleed screw then it's the filter with a small hole on top with a main seal.

Hex Head Present: slightly open the hex and turn on the ignition after replacing the filter which will activate the pump, once the air hisses out and turns to fuel close the screw and it should fire.

No Hex Head Present: replace filter, top it off with fuel if you wish, start car....drive on.

The housing will be full of fuel, if you can get a small hose and siphon that fuel out it's a bonus as there is generally oil and other crud that settles on the bottom, once this is out then just give the inside a rub with a rag.

The five hex head screw that lock the top and bottom together are quite soft and prone to stripping so don't over tighten. I've rounded out both the head of the screw and the threads below on the cylinder bit.

All of the above is based on having a 2004 1.9 TDI Altea, 2007 2l PD TDI Altea and 2008 2l CR TDI Leon.

porsche boy

FR85 wrote:

All of the above is based on having a 2004 1.9 TDI Altea, 2007 2l PD TDI Altea and 2008 2l CR TDI Leon.

Very insightful post however the OP engine is the 1.6tdi which has a bleed procedure via EOBD. It is possible to fill the new filter and possibly avoid airlock but a procedure is there for a reason.

Remember diesel is a lubricant and the injectors & pump won't last long if pr8ming the system is carried out by cranking the engine.

gk5000

Just done the oil so shall leave the fuel filter for another day.

Lots of discussions/arguments on the internet about this with some thinking the VW scansystem needed while others thinking topping up the filter housing sufficient.

Also, think this was being blamed for problems with pumps whereas the real problem was dirty dirty/laundered diesel.

My thoughts are: it looks like the High pressure pump is below the level of the filter so there is going to be some diesel in the pipe, so the pump shall remain "moist" while you change the filter. Then I doubt if cranking alone for 5 -10 seconds shall cause any problem if you do introduce some air - it's not a blow dryer.

If the car starts immediately which most says it does, then any air must have been purged quickly automatically.

So I'll probably go ahead and do it sometime in the future - though I've since found a service manual which states a 90,000 km service interval on fuel filters if using EU diesel.

barneygumble99

gk5000 wrote: »

Just done the oil so shall leave the fuel filter for another day.

Lots of discussions/arguments on the internet about this with some thinking the VW scansystem needed while others thinking topping up the filter housing sufficient.

Also, think this was being blamed for problems with pumps whereas the real problem was dirty dirty/laundered diesel.

My thoughts are: it looks like the High pressure pump is below the level of the filter so there is going to be some diesel in the pipe, so the pump shall remain "moist" while you change the filter. Then I doubt if cranking alone for 5 -10 seconds shall cause any problem if you do introduce some air - it's not a blow dryer.

If the car starts immediately which most says it does, then any air must have been purged quickly automatically.

So I'll probably go ahead and do it sometime in the future - though I've since found a service manual which states a 90,000 km service interval on fuel filters if using EU diesel.

If you sit in the car , radio off, turn on the ignition and if you hear a humming noise from under the back seat for about 5-10 seconds then there’s a pump in the tank. Replace filter. Turn ignition on for 10 seconds and off. Repeat 3-4 times. Start car.

9935452

gk5000 wrote: »

Just done the oil so shall leave the fuel filter for another day.

Lots of discussions/arguments on the internet about this with some thinking the VW scansystem needed while others thinking topping up the filter housing sufficient.

Also, think this was being blamed for problems with pumps whereas the real problem was dirty dirty/laundered diesel.

My thoughts are: it looks like the High pressure pump is below the level of the filter so there is going to be some diesel in the pipe, so the pump shall remain "moist" while you change the filter. Then I doubt if cranking alone for 5 -10 seconds shall cause any problem if you do introduce some air - it's not a blow dryer.

If the car starts immediately which most says it does, then any air must have been purged quickly automatically.

So I'll probably go ahead and do it sometime in the future - though I've since found a service manual which states a 90,000 km service interval on fuel filters if using EU diesel.

You might want to do the fuel filter a little more often than 90k kms.
A friend was having trouble with a peugeot partner van which was 3 years old. Went to the main dealer.
New fuel filter. The mechanic reckoned that fuel quality isnt as good as it was. With different additives and low sulphur.
He reckoned it should nearly be changed at every service