I have a 2013 Q7, TDI, 279,000 miles. I LOVE, LOVE, LOVE it. However, it is cold in Indiana and it is acting up. It seems that both NOX sensors are out and several glow plugs are out (3-4). I can start it in my garage, run errands, and it is fine. When I come home (avg temps are in the 20's right now) and park it in the garage, turn it off and restart, it is in limp mode. It will be about $2000 for the NOX sensors, $600 for glow plugs, and $200 to clean the DPF. We are not DIY-ers. In addition to this I use some oil. Apparently I have a small leak in my main seal. I use about a quart between oil changes. Just trying to decide whether to FIX it or DITCH it. I would like to drive it for 2-3 more years until my youngest gets her license and I can go to a 5 seater. I would love to hear everyone's opinions. TIA!

 

Does Indiana have emissions testing. If not, Remove the DPF and tune it. If they do, Then you need to decide if it's worth fixing and if not, What is the value of a car that needs fixing. I just put 4 grand into my 2010 but I have 199,000 KM's or 120,000 miles

 

Not sure where you getting those $$$ amounts from...Audi dealer (please, please...don't ever take it to the dealership for diagnosis or repairs), or a local indie shop, etc., but it does pay to shop around for your services rather than just trusting, hoping for the best, and overpaying significantly. Really, all the items you mentioned are absolutely normal, expected, time/age/wear related items...just typical stuff that goes out eventually over long-term ownership. None is a death-knell for the car giving up or an end-of-life signal.

Basically, if your intent/desire is to keep the paid-for Q7 another 2-3 years, and you know it's been well maintained, then it makes excellent financial sense to make necessary/prudent repairs to get it back up to snuff, and just leave the rear main seal alone.

However, even if you don't DIY at all, you can/should still buy an inexpensive VAGCOM scan tool/code reader so you can actually view the fault codes your Q7 has. This will help you stay ahead of common problem issues, or at least be aware of them, but more to the point, owning a compatible scan tool will help prevent you getting scammed by repair shops recommending services you don't need. This car is smart enough it will throw out a code for each sensor, glowplug location, etc., that is not functioning within normal parameters. For example, if the NOx sensors were failed, then the car would immediately be in a limp-mode when you start it, or you'd be getting a countdown to no-restart message on the dash related to the reductant/Adblue system that those NOx sensors control the feedback loop on, etc.

If you really want to make a well informed decision, then you pay a good mechanic to do a PPI (pre-purchase inspection) report for you, and they'll go over the entire vehicle end-to-end, top-to-bottom, and be able to tell you what it needs now, and in future.

Just to reiterate: Audi dealers are not a good place to take your old Q7; they just see a huge $$$$$ making opportunity when you drive up. Often times this is also true of local repair shops, as well, so you have to do your homework online, and ask other folks/neighbors for repair shop recommendations, etc.

 

Good advice above. I'd also say make sure your battery is not losing charge - a bad battery can throw all sorts of spurious errors. If you really had glow plugs out, it wouldn't start fine and it would miss / jerk a lot when you drive it so worth checking the battery before you scan for errors. The leak you have is worth fixing before it causes further damage, don't just keep topping up oil.. that's a great way to get a coked up and useless engine that needs a major rebuild or swap

 

No, there is no emissions testing in Indiana. And you're right, the car has no value in it's present state.

 

FWIW: A slow leak at rear main engine seal is an extremely normal occurrence on this TDI 3.0L engine as it ages, and is not something you would prioritize to repair with 279,000 MILES on the clock, and especially when the owner states he only desires to drive it a few more years.

A quart of oil for topping off between oil change intervals is definitely the way to go in this particular scenario compared to paying thousands of dollars to replace that individual oil seal just to save $10/year on oil costs. I always keep a full, unopened bottle of oil in my TDI when I take trips, and my TDI has never used a drop of oil between changes unless a part on it failed (turbo's oil seals in my case), but it pays to be prepared.

I do heartily recommend using a diesel fuel additive like Hotshot's EDT / EDT for Winter (anti-gel formula), etc., as that keeps the very expensive fuel system components humming along and singing that torque-laden TDI song...oh yeah, I went there! In extreme -10 to -16 degree F, cold overnights like we are currently getting (thanks for sharing, Canada!), diesel fuel's components thickens/Gels, which can keep your TDI from starting or make it struggle very heavily to do so, even when all your glow plugs are working fine. There is a heating system for the diesel fuel, but it won't prevent the fuel from gelling when the car is turned off and left outside in the cold or in uninsulated garage, etc..

 

Yeah - in that case a thicker oil that still complies with VW standards (or not, it is an older CRDI diesel for gods sake) should work. That Valvoline Restore and Protect, for instance - or better still, a Shell Rotella CK4 in a 5w or 15w 40 weight. As for fuel additives, I've used STP diesel fuel additive (cetane boosters, mainly) for a long time and it works beautifully.

 

There are a few youtube videos on glow plug replacement. Were it me, I'd go ahead and try it myself even though I am not a mechanic. Have you got a friend with some basic tools. As for the NOX sensors, I am probably wrong but others will know for sure if a tune will deactivate the need for them. You can buy a whole turbo back kit or just do a DPF delete. Rawtek sells the whole kit but the EPA is giving them a problem so they are not presently shipping to the USA. Another is https://mecevo.com/parts/touareg_and...9_to_2016.html or you can go with Darkside developments in the UK. If you buy a kit, You can get an exhaust shop to install it or a backyard mechanic. As for tunes, https://tunezilla.com/catalog/Audi/2...DI?ecu=Stage-1 You will notice the power increase. FWIW, if you have any remaining dieselgate warranty, Oil leaks are covered.

 

I'll just say that in most places, it is quite likely that your diesel blend (from the pump) is not sufficient to handle the cold spell you're seeing right now. As such, some of your issues may simply be a result of slight fuel gelling. I'd try running some Diesel 911 (in the RED bottle) through it to see if that helps. If it does, also get a white bottle of diesel anti-gel from the same company and add it as directed during fill-ups while it remains cold (if necessary).

The NOx system HATES cold weather. I had to replace multiple parts of that system, mostly pertaining to pumps, every 18 months or so while it was under the extended warranty due to my climate. I finally dumped that part of the controls at about 130,000 miles due to the looming expense of additional parts replacement. The cost of modification was similar to the cost of keeping the SCR system working... except that I didn't have to repeat the cost in 18 months!

 

If it were mine i would probably get it fixed. It way less than what you would pay for a new car. Just don't let things nickle and dime you to death. Thee is a point where you just get a new car.