pchansen

I'm at the point where I'm starting to do my own maintenance on our '11 TDi. The 75K is considered a major service. Really it's an oil and filter change, fuel filter change and an inspection. I've done the oil and am now going to do the fuel filter. I have the simple filter- just a silver tube with an inlet and an outlet. Simple enough. In reading up on the procedure, it seems some use VAG-COM to run the fuel pump to prime the system and others have been successful simply turning the ignition on a few times and waiting for the system to prime it's self. Has anyone had any luck using the latter method?

Edd W

On my A8 I did it that way, it's simple enough and the fuel pump can be heard as well as any air being expelled into the tank.

pchansen

Awesome! I ordered one and it will be in tomorrow. 75K service will now be complete for about $200!

brutus23079

pc, can you hear the fuel pump prime when you turn on the ignition? Can't speak to the '11 Q7 TDI, but on my '14 Q5 TDI (V6), I needed to use a VCDS to prime the fuel pump. I talked DIY procedures with my service dept when I took delivery. They said they get TDI vehicles in every year with destroyed fuel systems due to improper fuel filter changes. If you don't bleed the air out (priming), the High Pressure Fuel Pump disintegrates, sending little shards of metal throughout the fuel system. Destroys everything it touches. Service Mgr said the cost to repair is "roughly $7000" (a tad more than your $200 figure). Might be worth a call to your local Audi service dept if you're not sure what you need to do. Could save you some *major* repair bills...

cdnalpina

On my 04 Jetta TDI (yes I know it's a totally different vehicle but bear with me) the same sort of thing has to be done where the filter needs to be filled with fuel before you fire the car. On these cars we use a mighty-vac, or equivalent, to do this. Do you think using a mighty-vac on this system to suck fuel in through the filter until it is saturated is an option?

brutus23079

I've known folks who used mighty-vacs to bleed air out of fuel. Presumably depends on the type of fuel filter setup. My 2014 Q5 TDI has an inline fuel filter tucked under the vehicle on the passenger side. With the price of doing it wrong so insanely high, I'll stick with what I know works for me, i.e. the using VCDS to prime the fuel pump and bleed out the air. Did it once as a DIY and it worked like a champ...

pchansen

Thanks for all the responses. I ended up priming the system using a very high tech method. Before removing the old filter, I pinched the lines going to and from the filter with vice grips wrapped in tape( so as not to damage the lines). I purchased a pint paint container and filled it with clean diesel. I had some poly tubing laying around and stuck one end onto the output end of the new filter and sucked, with my mouth fuel into the filter until full. If you're careful, you can then install the new filter full of fuel and have only a tiny amount of air enter the system. I energized the ignition and let the pump run for a few seconds and then started the car. It started straight away with no hesitation. That was a week ago and no issues. Just for fun, I cut open the old filter and it's nothing more than a pleated paper element. Nothing cosmic- no water separator device, no proprietary Audi tech, nothing. You could replace this filter with something from a John Deer mower and be perfectly fine. The filter was absolutely clean as far as I could tell as well. As far as destroying your HPFP, I'm not saying it couldn't happen but that would suck to have a system the basically charges you $7000 to run out of fuel. I think one would be OK as long as you let the low pressure fuel pump (plus high tech priming method) purge the air out of the system by simply turning the ignition on.

brutus23079

Good feedback Paul. Good to hear your method worked . And if you can energize the fuel pump with the ignition, then I'd think you got that little bit of air out as well. You bring up a good point about fuel starvation. I'll have to ask the dealer if our TDIs have some way of saving the HPFP if that should happen (not that I ever plan to find out personally). Of course, we can guess their answer will be "Don't ever run it dry" and that'll be the end of it.

sjsuQ7

Great information. I am going to be due for service (55K major maintenance) on my 2011 Q7 TDI, from what I can gather the following items need to be replaced:

Air filter
Spark plugs
Oil & Oil Filter
AdBlue fluid refill
Cabin filter
Fuel filter - remove water only

Did I miss anything?

Also, does anyone know the torque specs for the spark plug?

Thanks!

Rattyinnz

Just going through the motions of changing the fuel filter on my 2007 q7 tdi. I have read that later models need vcds to prime the filter. Can anyone confirm the low pressure fuel fuel pump will run on a 2007 model with the ignition on. I have tried this and had a listen, something hums from around the fuel tank area but not entirely certain. I don't have vcds but would like to do this myself to save some $$