D4164T Volvo V50 1.6 Drive - PCV membrane cracked.

[RonniNH]

Hi everyone, new Volvo owner.

Got a good deal on a Volvo V50, but its of cause not without its problems, car starts fine, idles fine, but starts surging at around 3000 rpm, there is no codes stored, and the car is not in limp.

When the engine starts surging, it billows white/gray smoke, and it stinks like diesel fuel.

Found this when working on it, and i got a suspicion that the intercooler and turbo pipes may be full of oil, i have no idea on how long the pcv membrane has been torn, but there was oil in the intake pipe to the turbo.

Will a faulty PCV membrane cause power issues, does it cause a vacuum leak on a diesel ?

Kind regards
Ronni

[Vdx]

Excess oil vapour will have been drawn through the intake system. That could cause it to surge above 3K, being over fuelled buy the oil vapour. I think you are right to want to take off the intercooler hoses. It is normal though for the intake pipe to have a light coating of oil as some oil vapour comes out the breather hose with the diaphragm intact, but with it failed the vapour will have been excessive. If you take out the intercooler and tip it on end its probably full of oil.

I don’t think it is equivalent to a vacuum leak on a petrol. I think a vacuum leak on a petrol would cause a lean running condition, but a diesel runs lean normally. The excess oil vapour here is likely causing more of a slight over fuelling condition with the oil being used as fuel.

Also if your car has a DPF fitted it may be full of ash from burning lots of oil vapour. The diesel smell I’m not sure about. Your oil may be contaminated with diesel and it may be evaporating out of the crankcase with the oil vapour. Oil contamination is likely if the DPF is indeed full of ash and the car is attempting frequent regenerations - you would probably get codes for a blocked DPF though. Diesel smell and surging could also be bad injectors sticking open too long but I think that is less likely and also think you would get low rail pressure codes for that. Codes could have been cleared and take a few drive cycles to come back.

[RonniNH]

Thank you for the reply.

Im planing to remove the intercooler, and the boost hoses to drain and clean them when fitting a new PCV system, the car does have a DPF, but no codes, so maybe i caught it in time before making a total mess of everything.

I forgot to mention that at least one of the injector seals are bad, but not sure if that will have any impact on the rev problem.

When i bought the car i drove it home, it was about an 1 hour drive with no codes, or warning lights, don't think any codes had been deleted as it had a few for a faulty generator, and low battery (Generator has been replaced) but i don't think the codes got deleted after the swap.

[Vdx]

It is good that there are no codes after a long drive. I would watch out with the blowing injector seals though, you’ve probably heard already but in other applications of the DV6 engine (peugeots, citroens, fords) they are known for high rates of turbocharger failure and people often cite failed injector seals as a contributor (among a few other things). Hot combustion blow-by getting past the injector washer heats oil in the head on the way out and contaminates it with soot, potentially leading to blockages in the turbocharger oil feed down the line. Oil & filter change after sorting the injector seals out a good idea maybe?

[RonniNH]

Originally Posted by Vdx

It is good that there are no codes after a long drive. I would watch out with the blowing injector seals though, you’ve probably heard already but in other applications of the DV6 engine (peugeots, citroens, fords) they are known for high rates of turbocharger failure and people often cite failed injector seals as a contributor (among a few other things). Hot combustion blow-by getting past the injector washer heats oil in the head on the way out and contaminates it with soot, potentially leading to blockages in the turbocharger oil feed down the line. Oil & filter change after sorting the injector seals out a good idea maybe?

Fresh filters (fuel/oil/air) and fresh oil is on the way, will give the car a service when it gets here, already got the seals for the injectors, will need to service the brakes also, car has been standing for a few months.

I did read about the turbo problems, but i don't think there is any problems with this one, not yet anyway, car does have a full service book, and there is no play in the turbo, so im hoping all is good there.

I am however wondering if it can be a faulty injector causing the surging around 3000 rpm, and the heavy smoke with a powerfull smell of diesel.

[Vdx]

Bad injector seal will definitely cause smells, smell of untreated diesel exhaust and potentially a smell of raw diesel in there too. If they’ve been gone a long time and its left a tarry black mess people say that can smell a bit like meat cooking on a bbq.

Don't think the seals are causing the surging, most likely just the engine getting a bit of oil vapour from the PCV issue. Pretty sure that will go away with a new membrane. The surging we are taking about is present when you rev it at idle/in neutral right?

[RonniNH]

Originally Posted by Vdx

The surging we are taking about is present when you rev it at idle/in neutral right?

It is, but also when driving the car, it feels like it falls flat on its face when accelerating and going up hill.

[RonniNH]

PCV Valve replaced, intercooler removed expecting to find oil, but no. Im wondering if its an injector issue, or its the turbo.