Hi.,
My 2013 Q7 TDI recently came up with an engine code that basically said your #5 injector is dirty, although the car runs beautifully and pulls like a train. My mechanic wants to replace the injector at $CDN2K complete. I'm hoping that someone can recommend an injector cleaner that works and is compatible with the TDI system.

Thanks much in advance for your help.

Best,
Jonny

 

OK, so cardinal rule is you need to identify the actual fault code when posting about a fault code. Mileage on car is important related to life expectancy of specific parts, like the fuel injectors.

We can't really assess the issue detailed by the fault code if you only provide generalities regards to your own interpretation of the fault code. If there is an injector fault code, then there's a problem bad enough that it is telling you about it. If it's leaking fuel, it can kill your whole engine, just for example.

Your mechanic sounds like an Audi Stealer, although 2k Canadian don't buy what it used to...for reference, that would be $1376 USD at today's exchange rate. The new injector, if you buy the Audi, badge-engineered part # is gonna cost you waaay more than if you buy the OEM, Bosch fuel injector, so if you have to replace it be smart about sourcing your parts...overpriced is overpriced, no matter where you buy it from. Also, mechanics often charge you a 10-20% premium on the part cost just for sourcing it directly...padding their profit since they are getting the part at wholesale cost.

Here's the caveat. You didn't include mileage on car, and guess what; the fuel injectors require maintenance as the car ages...new copper seals for a good seal & o-rings for oil control are common injector services, etc. (I just did new seals on all my injectors at 120k miles to verify their condition and prevent known issues) They also can expand/mushroom on the firing tips, which is a sure sign of impending failure of the injector(s). Typically, the injectors lifespan is anywhere from 120k miles up to 180k miles, depending on how they've been maintained, quality of fuel used, etc., but they can fail earlier due to fuel system problems and/or HPFP failures.

We have no relevant details other than your mechanic is definitely licking his chops/drooling at the 'boat payment' he's gonna make off replacing your one fuel injector. The thing about fuel injectors is there are six of them on your TDI engine...not just one. Let that sink in for a moment.

How's about you get the exact fault codes your car is showing currently...all of them.

 

Hi 10Q,
Thanks for your knowledgeable and helpful reply. My Q7 has 125K miles (200K km) on it, so it looks like I'm in for some big expenses. I did not check the fault codes myself but I will dig out my meter and plug it in and get back.

Best,
Jonny

 

At only 125k miles, it's probably not nearly the end of the world, or your fuel injectors just yet, but more than likely you'll have a couple injectors where the oil seal (O-ring) may be failing/failed, and/or the sealing ring (copper washer) at the tip of the injector is about to breach, or is failed, as this washer eventually gets consumed/damaged. Your car can still run perfectly well with these problems, and normally you don't get a fault code on these 'normal wear' type issues, so that's why it's so important to know what this car is able to tell you.

I mentioned the point that there are six injectors in reference to the fact that they will tend to wear out as a set, although certainly you can have one be an outlier or get some crud stuck in it so that it leaks fuel, or doesn't spray correctly, etc. With a VAGCOM scan tool, you can also go into the Engine Control Module and look at the live data (engine running) for the fuel injectors balance/spray volumes to check for any obvious outliers. So there's a fair bit you can do if you have a decent VAGCOM scan tool besides simply read the fault codes. But start with the fault codes, and work your way out from there.

 

Might be worth replacing the fuel filter as an initial measure, unless you know it was done recently.

Depending on the recent weather in your location and the how much the car has been used, this could be a fuel waxing issue.

Some premium fuels have pretty good additives for this kind of thing. In Europe my preferences are Shell and BP/Aral.

Not sure how widely available it is but in the UK, Millers makes a good diesel injector cleaner. Beyond that, it’s probably worth throwing some money at any decent brand. STP, Liqui Moly, Motul, Würth, Amsoil, etc.

It’s worth making a note of the fault code and then clearing it around 100km after implementing whichever measure you choose so that you can see if it was effective.

Rumour has it that a small ratio of petrol can help but in that winter diesel is less oily in the first place, I would regard adding petrol as a big risk to some expensive components.

Be vigilant for any changes in engine behaviour (Audis are very good at concealing noise and vibration) and keep an eye on oil level, oil odour and fuel consumption. Spend a few minutes looking over the plumbing to the injectors to see if anything looks or smells leaky. I often find that a fault coincides with a recent repair or replacement… there are many halfwits masquerading as professionals.

If you do lots of short trips, find an excuse for a longer journey.

I hope my inane rambling has provided something useful. Good luck!

 

I think you meant well, however I don't see the relevance in posting harmful information:
NEVER ADD PETROL/GASOLINE, in any amount, into a diesel vehicle's fuel system!!!

Please be careful what you post, as not everyone who reads these threads is mechanically knowledgeable or DIY inclined. No need to reinvent the wheel here when the OP has a fault code/CEL to work from. We just don't know what that is yet.

 

You think I meant well?
I clearly stated that I view adding petrol as a big risk.
Please be careful what you presume before you post. I’m not sure you meant well. I think you intended to be condescending.