Buying a VW Diesel

[Greg Roles]

Hey all,

Had a nice chat with a member this morning who is about to buy a used Passat TDI, and he had been on here doing a lot of research. It dawned on me during our conversation it might be handy ( and save people reading a TON of threads ) to put a brief summary in one spot. Now I'm not here to be the only voice, so feel free to add your thoughts, but here's my humble opinion:

Which TDI??

MKV. The 103kw TDI in the various MKV cars would be my pick for a used vehicle.

It doesn't have the Siemens injector system that is causing so many failures in the 125kw version, and runs a Bosch system instead. VW has returned to Bosch entirely in the MK6, so I think that says something. For sure the 103 injectors can fail, but it's far less likely, and appears to be more typical failure- bad fuel, contamination - typical problems. The 125 has oil ingress into the Piezo stack, and even the new revised double o-ring ones can fail at any time without warning.

Also the 103 in the MKV's didn't have a DPF. In Skoda and Audi, some models were ahead of their time and did, but in the VW's you don't have that issue either. No regenerations, no odd running, no eventual and expensive clog.

If I bought a used 103kw, I'd first fit a Provent 200, readily available on e-bay or through me ( when I get stock in ) to reduce the oil into the intake. Essential item in anything with a DPF, as oil ash is what eventually clogs these things, it canlt be burnt off during regens like the soot.

The next step is optional, but I'd then chip it up to the 125kw level, and you end up with more torque. Any of the main companies can help you there, and the MKV's are all still flashable, so will work with a hand controller if you wish. This is the time to get the EGR coded down to virtually zero, as this helps the engine run a lot smoother, and again most tuners can handle this. For sure your emissions raise a little, but your engine will run a lot more effectively over it's lifetime, so I have to wonder if the net effect is about zero. A caked up TDI is going to have horrible emission levels!

If you don't want to tune the car, that's fine, and you can fit an EGR blanking plate with a 10mm hole drilled in it to stop the CEL dashlight error, but it will dramatically reduce the EGR levels. Plates are readily available on ebay, and I will have some shortly too. The hole needs to be at least 10mm.


MKVI: These all now have a DPF, so in my opinion the only essential thing to do is to fit a Provent. These new common rail TDI's are a LOT quieter and better off boost, and produce less soot overall, so they are a lot kinder to the DPF. The downside is they now have a motorside flap in the exhaust as well to aid regens, and this has been problematic on some cars so far in the USA, perhaps ours is different enough, but time will tell.

You can also have it tuned, although all the TDI's since about 2009 in VW are now antitune, so the ECU has to come out, and you can't use a handheld to swap at will. Again the main thing to have done is to code the EGR down, and again, as above if you don't want to tune it, a blanking plate with a hole in it is the go.

The main risk with the common rails is fuel contamination, and water especially becomes like a surgical tool at these pressures, so in a MK6 it's even more important to run the best diesel you can find, again Caltex Vortex or BP Ultimate if your state has it. I still recommend these diesels only in the MKV's, but they are a bit less effected by fuel.

I have been reading of a lot of high pressure fuel pump failures in the MK6 TDI's in the states, but not so many here, again may be a USA thing, but it's something to keep your eye on, the good news is given it's a model released in the USA, it's more likely to become an official recall if there is a problem, unlike the nonUSA 125kw Siemens injector issue, that VW is effectively sweeping under the carpet. Still there is now a TSI ( Tech Service Info ) bulletin on it, so effected cars should be getting things fixed for free for 7 years post sale.

But back to the main question, in the MKV's I'd be picking a 103 and chippping it up to 125 over picking a 125 given the risks.

Still my poor abused 125 hasn't stopped because of VW...yet......has done so a few times because of me!!

[vk]

Hey all,

Had a nice chat with a member this morning who is about to buy a used Passat TDI, and he had been on here doing a lot of research. It dawned on me during our conversation it might be handy ( and save people reading a TON of threads ) to put a brief summary in one spot. Now I'm not here to be the only voice, so feel free to add your thoughts, but here's my humble opinion:

Which TDI??

MKV. The 103kw TDI in the various MKV cars would be my pick for a used vehicle.

It doesn't have the Siemens injector system that is causing so many failures in the 125kw version, and runs a Bosch system instead. VW has returned to Bosch entirely in the MK6, so I think that says something. For sure the 103 injectors can fail, but it's far less likely, and appears to be more typical failuer - bad fuel, contamination - typical problems. The 125 has oil ingress into the Piezo stack, and even the new revised double o-ring ones can fail at any time without warning.

Also the 103 in the MKV's didn't have a DPF. In Skoda and Audi, some models were ahead of their time and did, but in the VW's you don't have that issue either. No regenerations, no odd running, no eventual and expensive clog.

If I bought a used 103kw, I'd first fit a Provent 200, readily available on e-bay or through me ( when I get stock in ) t6o reduce the oil into the intake. Essential item in anything with a DPF, as oil ash is what eventually clogs these things, it canlt be burnt off during regens like the soot.

The next step is optional, but I'd then chip it up to the 125kw level, and you end up with more torque. Any of the main companies can help you there, and the MKV's are all still flashable, so will work with a hand controller if you wish. This is the time to get the EGR coded down to virtually zero, as this helps the engine run a lot smoother, and again most tuners can handle this. For sure your emissions raise a little, but your engine will run a lot more effectively over it's lifetime, so I have to wonder if the net effect is about zero. A caked up TDI is going to have horrible emission levels!

If you don't want to tune the car, that's fine, and you can fit an EGR blanking plate with a 10mm hole drilled in it to stop the CEL dashlight error, but it will dramatically reduce the EGR levels. Plates are readily available on ebay, and I will have some shortly too. The hole needs to be at least 10mm.


MKVI: These all now have a DPF, so in my opinion the only essential thing to do is to fit a Provent. These new common rail TDI's are a LOT quieter and better off boost, and produce less soot overall, so they are a lot kinder to the DPF. The downside is they now have a motorside flap in the exhaust as well to aid regens, and this has been problematic on some cars so far in the USA, perhaps ours is different enough, but time will tell.

You can also have it tuned, although all the TDI's since about 2009 in VW are now antitune, so the ECU has to come out, and you can't use a handheld to swap at will. Again the main thing to have done is to code the EGR down, and again, as above if you don't want to tune it, a blanking plate with a hole in it is the go.

The main risk with the common rails is fuel contamination, and water especially becomes like a surgical tool at these pressures, so in a MK6 it's even more important to run the best diesel you can find, again Caltex Vortex or BP Ultimate if your state has it. I still recommend these diesels only in the MKV's, but they are a bit less effected by fuel.

I have been reading of a lot of high pressure fuel pump failures in the MK6 TDI's in the states, but not so many here, again may be a USA thing, but it's something to keep your eye on, the good news is given it;s a model released in the USA, it;s more likely to become an official recall if there is a problem, unlike the nonUSA 125kw Siemens injector issue, that VW is effectively sweeping under the carpet. Still there is now a TSI ( Tech Service Info ) bulletin on it, so effected cars should be getting things fixed for free for 7 years post sale.

But back to the main question, in the MKV's I'd be picking a 103 and chippping it up to 125 over picking a 125 given the risks.

Still my poor abused 125 hasn't stopped because of VW...yet......has done so a few times becasue of me!!

This makes me feel like I need a provent, but I didnt even know what it was till now. :S

[ForceFed]

Makes me feel warm inside that I purchased a 103kw TDI...Now to tune it and get the EGR values down.

[vk]

Makes me feel warm inside that I purchased a 103kw TDI...Now to tune it and get the EGR values down.

This one just popped up on ebay :O
eBay Australia: Buy new & used fashion, electronics & home d

[mk5_tdi]

That one has been on eBay for quite some time, maybe off/on as i don't check regularly
When i purchased my tdi in late January this year and even before in late last year when i was looking for tdi's that was trying to be sold