Coolant leak - Investigation ideas

[RobertO2023]

I’ve Never come across DMF causing an engine running issue ! Glow plugs have no relevance after the engine has started. Get the diagnostic test run several times eliminating non issue codes. I’m guessing it’s a MAFM problem which can throw up the reduction in power output. Coolant loss totally different issue. head Head gasket failure is well know between 3 and the water jacket that won’t throw up the power loss that you describe. Good Luck

 

[Fasty-123]

Thanks Dxx, what would the oil analysis show? Bits of metal that are going to lead to total destruction!? I hope not. The specialist I took it to assured me that when they took it apart there was no sign of internal damage, or bore score. They seemed confident it would be fine, but I’m seriously worried now. Difficult to know what garage to trust. They did a full oil change and cambelt water pump with the head.

 

[DXX]

If you’ve had an oil change there’s nothing worth sampling.
You’re mentioning the need to renew injectors, generally that’s because the injectors are damaged and leaking fuel which ends up in the engine oil, DPF and EGR as soot.
I suggest you post the known history with dates and mileage, any parts renewed, whether the symptoms changed after renewal and fault codes.

 

[Fasty-123]

I’ve Never come across DMF causing an engine running issue ! Glow plugs have no relevance after the engine has started. Get the diagnostic test run several times eliminating non issue codes. I’m guessing it’s a MAFM problem which can throw up the reduction in power output. Coolant loss totally different issue. head Head gasket failure is well know between 3 and the water jacket that won’t throw up the power loss that you describe. Good Luck

Hi Robert,

The reason I say dmf is the metallic knocking noise I described sounds like this

Could be just another issue unrelated and another failing part to spend money on.

The glow plugs was thinking maybe because of the ‘post glow’ the euro 6 is equipped with.

 

[Fasty-123]

Just done a video of it on start up…

 

[Fasty-123]

If you’ve had an oil change there’s nothing worth sampling.
You’re mentioning the need to renew injectors, generally that’s because the injectors are damaged and leaking fuel which ends up in the engine oil, DPF and EGR as soot.
I suggest you post the known history with dates and mileage, any parts renewed, whether the symptoms changed after renewal and fault codes.

Ok thanks dxx will collate that info and post

 

[mmi]

Specialist now suspects injectors and wants to put a new set in.

Were the injectors tested per VW procedure (below)

[T6_measured] Injector failure

Keyword “loud knocking metallic noise from engine”. VW has published in September a service note which can be found with vehicle's VIN. The sound clips from my engine (150PS, EU6) with comments on 21 Oct 2017 in thread Tick over noise EDIT: audio files from the thread copied here as...

www.t6forum.com

Just done a video of it on start up…

Sounds like the DMF pendulums are hitting limiters - they just can't absorb such a big imbalance roughly running engine. If that doesn't happen when engine is running normally I'd leave it for now.

The glow plugs was thinking maybe because of the ‘post glow’ the euro 6 is equipped with.

The glow plugs are monitored so I would expect to see fault codes if any of them would not not work. Also it seems that a non-working glow plug doesn't cause rough running, e.g.

Glow plug circuit open / fault code

Hi, Randomly getting the orange engine dash warning on my 2020 T6 204hp. I can clear it with Carista and the engine warning lamp disappears. Not getting any limp mode or anything. The fault code is suggesting open circuit / fault on cylinder 1 glow plug, but I am not experiencing any issues...

www.t6forum.com

As always I would start checking that engine's speed sensors produce proper signals - crankshaft sensor was the culprit here

204 DSG intermittent momentary power loss

I'm not sure. I'll do similar runs with mine (same CXEB engine) to get more data. A 30 minute capture today didn't have any of the drop-outs with these - but I didn't push it that much. IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value IDE07793 Turboc.1 turbin.bypass valve 1 B...

www.t6forum.com

If you hold the revs above 1500rpm it smooths out.

Related to engine's speed sensors - it's at approx. 1500 rpm where camshaft speed sensor "fades out" and engine runs solely on crankshaft sensor - of course could be just coincidence or simply consequence of inertia.

 

[Fasty-123]

Were the injectors tested per VW procedure (below)

[T6_measured] Injector failure

Keyword “loud knocking metallic noise from engine”. VW has published in September a service note which can be found with vehicle's VIN. The sound clips from my engine (150PS, EU6) with comments on 21 Oct 2017 in thread Tick over noise EDIT: audio files from the thread copied here as...

www.t6forum.com

Sounds like the DMF pendulums are hitting limiters - they just can't absorb such a big imbalance roughly running engine. If that doesn't happen when engine is running normally I'd leave it for now.


The glow plugs are monitored so I would expect to see fault codes if any of them would not not work. Also it seems that a non-working glow plug doesn't cause rough running, e.g.

Glow plug circuit open / fault code

Hi, Randomly getting the orange engine dash warning on my 2020 T6 204hp. I can clear it with Carista and the engine warning lamp disappears. Not getting any limp mode or anything. The fault code is suggesting open circuit / fault on cylinder 1 glow plug, but I am not experiencing any issues...

www.t6forum.com

As always I would start checking that engine's speed sensors produce proper signals - crankshaft sensor was the culprit here

204 DSG intermittent momentary power loss

I'm not sure. I'll do similar runs with mine (same CXEB engine) to get more data. A 30 minute capture today didn't have any of the drop-outs with these - but I didn't push it that much. IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value IDE07793 Turboc.1 turbin.bypass valve 1 B...

www.t6forum.com

Related to engine's speed sensors - it's at approx. 1500 rpm where camshaft speed sensor "fades out" and engine runs solely on crankshaft sensor - of course could be just coincidence or simply consequence of inertia.

Thanks @mmi all info very helpful. I have been busy reading through.

With regards the injector leak off test, this wasn't offered by the garage he just wanted to stick a set of four in and see if it made a difference. No Fault finding or diagnostics involved. I think he's just too busy to try and work out what the problem is. I think I need to find someone else or resort to trying to fix it myself.

One interesting thing I noticed over the last few days is, the longer you leave it between starts the worse it gets. So start stop during the day, starts again no problem and runs fine. Leave it for 5 hours it's a little bit rough and clears up fairly quickly. Leave it overnight and it's quite bad and takes a while to clear. Leave it for two days and runs really rough like the video. I've also noticed it smells very strong of fumes around the vehicle.

So I was thinking what if one of the injectors was leaking fuel into the cylinder when it's off. Could this cause the engine to run that rough? If so what would be the best way to test my theory?

GSF do a crankshaft sensor for £25 quid so I could just stick one in to rule that out.

One thing I forgot to say to help everyone else with diagnosing coolant loss, to rule out head gasket check if the coolant tank is pressurised when cold along with a combustion test.

Thanks all

 

[Fasty-123]

Thanks @mmi all info very helpful. I have been busy reading through.

With regards the injector leak off test, this wasn't offered by the garage he just wanted to stick a set of four in and see if it made a difference. No Fault finding or diagnostics involved. I think he's just too busy to try and work out what the problem is. I think I need to find someone else or resort to trying to fix it myself.

One interesting thing I noticed over the last few days is, the longer you leave it between starts the worse it gets. So start stop during the day, starts again no problem and runs fine. Leave it for 5 hours it's a little bit rough and clears up fairly quickly. Leave it overnight and it's quite bad and takes a while to clear. Leave it for two days and runs really rough like the video. I've also noticed it smells very strong of fumes around the vehicle.

So I was thinking what if one of the injectors was leaking fuel into the cylinder when it's off. Could this cause the engine to run that rough? If so what would be the best way to test my theory?

GSF do a crankshaft sensor for £25 quid so I could just stick one in to rule that out.

One thing I forgot to say to help everyone else with diagnosing coolant loss, to rule out head gasket check if the coolant tank is pressurised when cold along with a combustion test.

Thanks all

Oh and forgot to say think your definitely right regards the DMF I got right under it the noise is definitely coming from that area. So must be the engine running so rough it's taking it out on the DMF.

 

[DXX]

If so what would be the best way to test my theory?

Miller oil analysis, about £50, will give the fuel dilution and other contaminants in the oil. Data entered in the test info’ must be accurate.
Syringe and 1.5m of hose that will fit down the dipstick is needed to take the sample.

 

[RobertO2023]

Have you run full diagnostics? Any fuel pressure errors, fuel pressure control valve, pump etc……

 

[Fasty-123]

Hi All, got to the bottom of this is issue. Was displaying no fault codes. The injector on cylinder 4 was leaking into the cylinder after engine was switched off. New injector in and seems to of sorted it. However the dmf is still knocking when cold and the the dpf is now saying it’s blocked. The list of woes continue.

 

[mmi]

the dpf is now saying it’s blocked.

How does it tell that?

 

[Fasty-123]

After a week with new injector. I got an engine light and read the code and it says 32110 particulate filter. I’m thinking because it’s put so much unburnt fuel through, it’s clogged up the DPF. Have a guy coming out today to clean it out.

 

[mmi]

I got an engine light and read the code and it says 32110 particulate filter. I’m thinking because it’s put so much unburnt fuel through, it’s clogged up the DPF.

Hmm...

32110 - Diesel Particulate Filter (Bank 1) - P226D 00 [236] - Damaged or Subrate Missing​

​

Is the tailpipe sooty?

 

[DXX]

@Crippso what was the outcome of your vans coolant leak investigation as this thread migrated a bit?

 

[Fasty-123]

Fairly full of soot @mmi but not too bad.

Sorry my fault the thread has gone off on a tangent.

I wonder if my coolant loss and blown head gasket, has contributed to some of the issues that followed. Or if a T6 is made to last for a 100k before everything falls apart.

 

[Crippso]

@Crippso what was the outcome of your vans coolant leak investigation as this thread migrated a bit?

Thanks @DXX So in my last post I said the plan was monitor after the expansion tank cap replaced. Since then, nearly 900 miles later and I'm sad to say it does appear to be losing coolant still. Maybe around 200 or 300ml. No sign of wet coolant under the tank anymore since cap was replaced though. But perhaps it's being lost somewhere else now. I've noticed after a few drives the radiator fan is going like mad for a few minutes after engine shutoff. And one time I also spotted almost like boiling in the tank, again after shutoff. Not sure how relevant that might be. But I'm planning to book it in with a VW garage in the hope they will be able to get to the bottom of it. Another odd thing.. the other day I had ignition on for a few minutes before I started engine. For the duration of short journey the orange coil warning light was flashing , engine ran fine. No sign of that in a good few drives since. May not be related but thought I'd mention it
Thanks
Stuart

 

[roadtripper]

I've noticed after a few drives the radiator fan is going like mad for a few minutes after engine shutoff.

Was it doing a regen when you shut it off in these cases, as the whole system temperature will be somewhat raised during that process.

 

[DXX]

Thanks @DXX So in my last post I said the plan was monitor after the expansion tank cap replaced. Since then, nearly 900 miles later and I'm sad to say it does appear to be losing coolant still. Maybe around 200 or 300ml. No sign of wet coolant under the tank anymore since cap was replaced though. But perhaps it's being lost somewhere else now. I've noticed after a few drives the radiator fan is going like mad for a few minutes after engine shutoff. And one time I also spotted almost like boiling in the tank, again after shutoff. Not sure how relevant that might be. But I'm planning to book it in with a VW garage in the hope they will be able to get to the bottom of it. Another odd thing.. the other day I had ignition on for a few minutes before I started engine. For the duration of short journey the orange coil warning light was flashing , engine ran fine. No sign of that in a good few drives since. May not be related but thought I'd mention it
Thanks
Stuart

As @roadtripper mentioned above it sounds like you stopped during a DPF regeneration. Carista Beta will show when the last re-gen was carried out, plus many other useful functions. An engine coolant system temperature will briefly rise just after shutdown as the airflow over the radiators is stopped and the engine is still dissipating residual heat.
My advice is still as Post #4.