Help with blue smoke bellowing out bonnet compartment

[Handyandy]

I have an intermittent fault with blue smoke bellowing out of engine bay especially while driving slow I thought the fault was a leaking turbo return oil pipe into block was a problem as there was a slight weep this has now been rectified but problem persists and the smell of oil is quite strong
I have checked the oil level quite a few times and level is OK also no evidence of oil patch on driveway so am at a loss at what the problem is and why the problem is only intermittent as its only happened 4 times in the 5 last months and the van is driven daily

[Dextersaurus]

Check the pipe that comes out of the valve cover and goes to the intake pipe. If that pops off you'll get a lot of oil vapour

How bad is the smoke? You say billowing but are we talking a slight visible vapour or thick blue smoke?

[Handyandy]

We are talking smoke that can fill the cab on the worst time but a lot of smoke coming from around the bonnet as soon as you lift it up it disperses and you see a little bit on the cambelt side but nothing excessive if I'm sitting in traffic and it starts smoking you get a lot of funny looks as if the engine bay is on fire

[Dextersaurus]

If there are no signs of a leak I'd be checking the exhaust if it's that much smoke. I'm assuming from your sig that the DPF etc are mapped out but you might have a blown gasket somewhere?

Only so many things that are hot enough or oily enough to create that much smoke

[Handyandy]

Dpf is still functioning as normal I've checked exhaust today but couldn't see anything obvious especially around the dpf box when you say blown gasket are you on about exhaust gasket as that I thought would blow all the time

[BenT]

Get a small, bright torch and have a look under the bonnet with the engine running after dark. You should then be able to pinpoint exactly where the smoke's coming from as it'll show up in the torch beam.

[BenT]

A laser pointer may actually work better come to think of it, because of less reflection

[Dextersaurus]

When you say blown gasket are you on about exhaust gasket as that I thought would blow all the time

Yes I meant exhaust gasket. My thought process here was that yes a gasket would be leaking all the time (but likely worse when hot) but it's only when the EGR is operating or the DPF is regenerating that you're getting the smoke hence the intermittent nature.

It's a guessing game really, you're going to have to get it to start smoking then get your head right in and about and underneath it to try to find it.

[Handyandy]

I was thinking again last night about this and was wondering that it only seems to happen when I'm driving slow or stuck in traffic and that it may have something to do with the dpf and regeneration but that's only my thoughts

[PeterAFox]

I've seen similar - it wasn't that it only happened when driving slow, just when you drive faster the smoke is blown away.
It was a leaky pipe to the rocker cover