Just changed fuel filter on MK3 (went good)

[Ryan_Tango]

Yeah well just changed the fuel filter after some serious power loss amongst many other problems it was causing, Halfords quoted me £82 to do it for me including a new housing which he said their would be no chance of it starting without the housing, I thought I am not paying £82 for something I could do my self, turns out they were wrong you don't need to replace the housing as evidenced by some googling. 

I purchased a priming bulb which was as much use as a chocolate teapot after ages trying to get diesel to come through I give up it wasn't even pumping the fuel through it wasn't strong enough for the job at hand and I was getting soaked with all the rain (Covered my engine bay with a tarp to protect whatever needed protecting but my back got soaked)

I had a quick google to see if I could find any hints to self priming well found nothing really relevant to my car so I thought just try turning the key to position 2 a few times (Don't know if this was any help but worth a shot I figured) then I turned the engine on it fired straight up, the revs bounced up and down as though it wanted to cut out so I give it a few revs and it smoothed it self out thankfully, just been for a 40 mile run, restored power it's even quicker than when I bought it (Second hand).

 

It's actually a really easy procedure I followed my Haynes manual apart from the priming of the filter seems to have done that by it self thankfully otherwise I'd be kicking my self right now. 

 

[TomsFocus]

That was very lucky lol!!

Turning the key does nothing on these as there's no in tank pump.  It should require the hand pump unless you filled the new filter with diesel.

[iantt]

agree, very lucky. can take quite some cranking if not bled through with primer.

[Albert27]

Sorry to bump this thread but I've just bought a mk3, and its service is due. Was planning to change fuel filter as although has full history, doesn't say what was changed when. I was going to skip any priming as that failed last time on my Mk 2.5, and just get a tow start. Any downside to this?

[TomsFocus]

The pump is lubricated by the diesel flowing through it, a tow will obviously spin the pump up quickly without any lubrication so not ideal.

Hand priming is the way to go really.  Just make sure you get a decent primer this time.

[iantt]

dont buy a laser primer, useless.
buy a large syringe and suck the fuel through.

[stef123]

what engine was this on? 
I changed the fuel filter on a mk3, 2.0 diesel not so long ago, I didn't even disconnect the fuel lines I just unscrewed the lid and lifted it up enough to get at the filter. It fired back up straight away without complaint. 

[iantt]

2.0 is easier. alberts is the 1.6 i think.

 

 

 

[iantt]

1.5 mk3,5 is easier still. switch ign on and wait 30 secs . pump on 1.5

[Albert27]

Yeah it's 1.6 tdci on both.  I think the primer was ok (Draper) , more my method being the problem I suspect!  Will just cranking eventually draw enough diesel through?  I'll try a bit of priming and some cranking again, and at least I can fall back on the tow start. Did that a year ago on the other one and it has been ok since but will keep it as a last resort.  With a bit of practice i might even get good at it and avoid the embarrassment of neighbours watching me bump start two cars in 12 months I'm suppposed to be 'servicing';  They'll think I'm crap at mechanics.......

[TomsFocus]

In theory it should start eventually from just cranking, but you'd probably run out of battery first lol.  And again, the pump is spinning up dry for longer than is ideal, albeit not as quickly on the starter as a tow.  

It partly depends on how quickly you change the filter as well, the less time the fuel lines are open, the less time there is for the diesel to run back to the tank.  

I've got a Lucas hand primer from an old mechanical Diesel Peugeot, much better than the cheap aftermarket ones.  Just have some tape ready to temp seal any minor leaks as it needs to be air tight on the piping, and make sure you're holding it correctly so the one-way valve works properly.  Should only take a few seconds to suck the fuel through if you've got the primer right.  

[Albert27]

1 hour ago, TomsFocus said:

In theory it should start eventually from just cranking, but you'd probably run out of battery first lol.  And again, the pump is spinning up dry for longer than is ideal, albeit not as quickly on the starter as a tow.

If I filled the new filter with as much diesel as i could, then went for an immediate tow start,  would there still be diesel left over in the lines and in the pump?  What i'm wondering is, if a tow start is done immediately then the pump only runs dry for a very short period and has some lubrication? As opposed to tow starting after you've cranked and cranked...... Anyway, I'll let you know how i get on!

[TomsFocus]

If you fill the new filter, and swap it quickly (so get the old one ready to move, then pull the lines off at the last minute and on to the new one asap) you may get away without a hand primer.

Also don't loose it once it starts, be ready to mash the throttle if it starts to cough.