Fumes - not the EGR Flexi

[CJW]

Hi

I've really bonded with my van and will post some pics soon of the conversion. Right now I'm trying to solve a problem and I'm running out of ideas and things to check and hoping that someone with more Transporter experience than me might spot something I've missed. Here's the situation:

Driven for 3 months without any issue, then drove 200 miles each way to have the bed / seat fitted. I'd just finished the deadening, insulation and lining a few days before the journey. On the way down I could smell exhaust fumes. On the way back it was really strong and made me woozy. Things I've checked:

• Not the EGR flexi because this is a CAAC engine. I can't see any soot on EGR pipes, there's no hissing when revved, and no smoke.
• Don't think it's the exhaust manifold - have revved it and felt around - can't detect anything and no soot.
• Nothing appears to be leaking from the turbo when revved.
• No apparent leaks from the exhaust system down to rear.
• Not the cabin filter - I replaced it.
• Not the AC low on coolant and burning itself up - AC works and fluid level within range.
• I checked the bungs in the under tray - all present and correct.
• AC / vents work as normal.
• No error codes
• No auxiliary heater - at least it's not on the build sheet and no stickers on the doors.
• Not DPF regen - been monitoring on Carista.
• Tailgate seal is old but no holes in it.

Seems to not be an issue at all when driving when the windows are closed, but with them open just a crack, it doesn't take more than a couple of miles' journey before the rear and the cabin smell distinctly of fumes. My current line of thinking is that both me and the better half drive with the windows open a crack by habit - is there a possibility that this behaviour is taking air out of the interior, forcing it to be drawn in through some other route (fume-laden air) that has changed because of the lining / insulation? Or have I missed some other engine-related possibility?

Here's hoping some kind person has been through similar, or others have ideas of things I haven't checked yet.

JULY 2016 EUR5 T6.0 T32 2.0 TDI 140BHP BMT LWB ST-LN Variant: GCAAC320X0

Chris

 

[mmi]

Leisure battery?

 

[CJW]

Not yet installed.

 

[BoroBoy]

Is your exhaust pipe, the short version and exhausting halfway down the van?

 

[CJW]

Is your exhaust pipe, the short version and exhausting halfway down the van?

It exhausts well before the end of the van. I’ve just been outside - here’s a photo:

 

[CJW]

@BoroBoy I see what you mean - some 2018’s had a pipe that stopped very much in the middle. That must be a pain for converters.

 

[bluezie]

Are you 100% sure it's not the exhaust manifold? I've seen one crack between cylinders 2 and 3 near the turbo. It was only just visible from below, not much soot, and it was only discovered when removing the cylinder head.

 

[BoroBoy]

@BoroBoy I see what you mean - some 2018’s had a pipe that stopped very much in the middle. That must be a pain for converters.

@CJW - Yeah, my exhaust terminated halfway down the van.

 

[CJW]

Are you 100% sure it's not the exhaust manifold? I've seen one crack between cylinders 2 and 3 near the turbo. It was only just visible from below, not much soot, and it was only discovered when removing the cylinder head.

I’ve only been able to do a visual and feel for leaks. There are parts of the manifold I can’t see so that’s certainly possible - last resort is to take it to a workshop and that’s looking pretty likely.

Are you 100% sure it's not the exhaust manifold? I've seen one crack between cylinders 2 and 3 near the turbo. It was only just visible from below, not much soot, and it was only discovered when removing the cylinder head.

Would you expect a loss of power or does it depend on the crack / gasket failure? I haven’t lost power.

 

[bluezie]

If the leak is small, then you won't notice any power loss, as the N75 / VNT control of boost will have some reserve left. As the leak gets worse, then boost will come on later in the rev range.
It doesn't take much of a leak to create horrible fumes, as these are un catalysed and un filtered exhaust fumes!

 

[CJW]

If the leak is small, then you won't notice any power loss, as the N75 / VNT control of boost will have some reserve left. As the leak gets worse, then boost will come on later in the rev range.
It doesn't take much of a leak to create horrible fumes, as these are un catalysed and un filtered exhaust fumes!

Thank you. That has to be a candidate then. Trying my best to avoid taking it in but hey - running out of other options. Thanks again.

 

[Mud Digger]

have a look at your rear door seals are tight against the door as the cab is depressurized with the windows cracked open might let the tail vortex in as you say its old might of flattened off a bit

 

[CJW]

have a look at your rear door seals are tight against the door as the cab is depressurized with the windows cracked open might let the tail vortex in as you say its old might of flattened off a bit

Hi. Thank you - I hadn’t thought about deformation. I did take the seal off when I lined the rear with carpet and didn’t make a note of where the join sat - it’s possible that when I put it back on, a flattened bit is now in a key location under less or no pressure. I’ll put a tiny bead of washing up liquid all around the contact line on the tailgate and give it a normal slam closed and see if there are any points where the liquid hasn’t transferred to the seal. Thanks again.

 

[Mud Digger]

Hi. Thank you - I hadn’t thought about deformation. I did take the seal off when I lined the rear with carpet and didn’t make a note of where the join sat - it’s possible that when I put it back on, a flattened bit is now in a key location under less or no pressure. I’ll put a tiny bead of washing up liquid all around the contact line on the tailgate and give it a normal slam closed and see if there are any points where the liquid hasn’t transferred to the seal. Thanks again.

or a sheet of paper/card did you not follow original outline of seal it should of had a slight shape to the seal

seam join on mine was bottom edge right hand side about 8 inches in did the seal ends butt up and join without a gap

There is a VW fume problem on these is why the air Fan speeds up when reversing over the exhaust fumes. unless thats for something else

 

[Big Al]

Quote:.........There is a VW fume problem on these is why the air Fan speeds up when reversing over the exhaust fumes. unless thats for something else

The heater control changes to `re-circulated air` automatically when reverse engaged for fumes, and swops back to fresh once reverse gear has been de-selected.

 

[CJW]

Thank you @Mud Digger and @Big Al - thanks for letting me know where the join is supposed to be. I will check where I put mine.

 

[CJW]

Hi. Thank you - I hadn’t thought about deformation. I did take the seal off when I lined the rear with carpet and didn’t make a note of where the join sat - it’s possible that when I put it back on, a flattened bit is now in a key location under less or no pressure. I’ll put a tiny bead of washing up liquid all around the contact line on the tailgate and give it a normal slam closed and see if there are any points where the liquid hasn’t transferred to the seal. Thanks again.

Well. The 6 year old seal clearly has parts that are more and less squashed. Those parts are not symmetrical as I’ve got it fitted now but I bet they were before I moved the seal. I seem to have rotated it so the join is bottom left. Using the washing up liquid technique, there’s a stretch at the bottom that has no contact at all and must be 3mm+ off since I blobbed a big bead on in that area and it still didn’t touch. The timing would be perfect too - I put the seal back on 24 hours before the problem journey. Thanks for your idea @Mud Digger - there’s enough evidence there in my mind to support buying a new seal before I have to spend a lot more at the garage.

 

[Mud Digger]

@CJW glad you found something to help eliminate the problem, but maybe just your door catch just need moving in a little to pull door in a bit tighter

 

[CJW]

Good idea. I’ll do that first.