Exhaust fumes in cabin and black soot on turbo

[blaast]

I started noticing exhaust fumes in the cabin of our 2009 T5 Caravelle (BNZ engine with 125,000kms).
A check under the bonnet revealed black soot on the turbo and surrounding area, including the firewall.

Does anyone have any thoughts on the cause of this exhaust leak?

I'm concerned that this could be $$$$...but hoping it might be simply knowing which bolt/s to tighten.

Our 'bus' plays a vital role in our family of 6 for transporting our children with disabilities, including a racing wheelchair to attend athletic events, so we can't afford for it to be out of action for too long.

Thanks in advance!

[Silver Caravelle]

Hi there,

First to check is whether the turbo to exhaust down pipe flange bracket is tight. You will need an allen key and maneuver your hand down there to check and tighten. This is the cheapest zero cost fix. However, if that flange gasket needs replacing or there is a leaking or cracked manifold or, turbo gas leak, I suggest getting it to a mechanic quickly to resolve.

Regards,

Scott

[Greg Roles]

The exhaust manifold studs for sure, common issue.

Typically the end head studs snap as the manifold heat cycles and warps unevenly. Mine broke one stud on the first cylinder ( drivers side ) and both on cylinder 5 ( passenger side ). You'd be best to put an aftermarket one back on, but given the time delay on parts and your need of the car that may be tricky. Genuine won't be cheap, and a used one would be a time bomb. I got an aftermarket cast one from Darkside Developments out of the UK who are quite prompt, but you will be looking at a good week for delivery at best this time of year, and putting it on is a decent task, rear engine support off, turbo off, get broken studs out with welder or reverse drills / ezi outs. Afraid it's not a quick and easy repair, nor will the labour charge be small.

You can drive the car in the meantime, but it will quickly become a noisy, sooty nightmare, so order the parts and get it fixed asap.

Here's a link to the darkside part, I figured a cast one other than genuine *may* hold up better than the VW one.

Darkside Developments - Transporter T5 2.5 TDi 5 Cylinder Cast Manifold for BPC / BNZ

[Umai Naa!!]

Also check the EGR cooler flange, where it bolts to the exhaust manifold.

Common to just break clean off. They can be re-welded, but do fail again. Tooley Imports has replacement coolers for around $650. About half the price of a genuine one.

[blaast]

First to check is whether the turbo to exhaust down pipe flange bracket is tight. You will need an allen key and maneuver your hand down there to check and tighten. This is the cheapest zero cost fix.

I think I found this bolt which I was able to turn nearly twice to tighten.

I've attached a couple of pics taken from above, looking down.
First pic shows the allen bolt on the right I tightened. There was no soot around this though.
You can also see the black soot on the turbo and heat shield.




In the pics below, you can see soot around the bolts located below the sensor.
Based on how the soot has covered these bolts (last pic), it looks like the soot is coming from this part.

Close up of bolts and soot from previous pic.

[Umai Naa!!]

Try tightening them up.

But be warned, they might snap.

There are two gaskets under there, but you'll need to remove the turbo and manifold to do it.

[Greg Roles]

The thick graphite wedge style gasket has probably failed, it has a weird crush type design. My Haynes manual only lists 25nm on those three turbo flange triple square screws, which sure isn't that much. If that's all the leak is you have little to worry about apart from the noise and mess, you can get it fixed when you can spare the car, it isn't the typical cracked / broken stud issue from the look of it. I'd suggest forgetting about it, ordering the three new bolts, and when you get them put in new bolts and tighten down to the 25nm. I reused mine just fine, but they are stretch bolts so as warned above they *can* snap, I did however put in a new graphite wedge crush gasket. If this doesn't fix it you will need to get a new gasket set put in, but end of the day it's not an urgent thing at all. My leak from the manifold had the entire engine bay coated with soot, including the god damn battery, so you are a long way from that!