Part two: Swapping over the 2.0 CDTI turbocharger.
We’ve had an anxious few weeks since buying and collecting our Insignia before Christmas. The low oil pressure warning is the major cause for concern. According to Vauxhall, if the engine oil is shown to be overfull on the dipstick, this is often a sign of an incomplete DPF regeneration. Allegedly, there’s no way of telling when a regen is happening, so if the engine is switched off, the process isn’t completed. The consequence of this is that diesel fuel is dumped into the engine oil, resulting in the overfull reading.
During a DPF regen, the engine runs rich to heat up the exhaust system and DPF. If the engine is switched off during a regen, there may be excess diesel fuel inside the cylinders which hasn’t been combusted. This can seep past the piston rings and into the oil, increasing the volume of oil with fuel. We suspect this is the case with our Insignia’s engine.
We had our Insignia transported to our local garage, MJ Motors in Batley, for a second opinion and to devise a plan of action for the low oil pressure problem. If you take a look at Your Letters this month, you’ll find that several readers have already written in with advice – including a couple of useful methods of recognising when a regen is occurring. Our sponsors, Autovaux, have also been very helpful.
Dan Smith at MJ Motors suggested running the engine so that he could see the problem for himself. Straight away, he could tell that the turbo was noisy. He detached the oil feed pipe to the top of the turbo and no oil spurted out. It had clearly been starved of oil.
So the turbo definitely needed renewing. The engine oil pick-up pipe that we discussed last month should also be replaced as it’s a common cause of low oil pressure if it has perished. However, the Vauxhall technician we spoke to explained that, if you’re lucky, changing the engine oil can fix the low oil pressure problem. We weren’t so optimistic, but tried this approach anyway. Sadly, it didn’t help.
A replacement turbo was needed. We contacted Autovaux, who were able to supply a remanufactured GM turbo for £438 (recommended retail price through Vauxhall is £715.20). So a turbo was delivered to MJ Motors along with a selection of gaskets and several other parts that we will be fitting over the forthcoming months. We’ve managed to renew the turbo this month, but not fix the low oil pressure problem, yet. We have however, managed to successfully renew the nearside rear wheel bearing, although removing the old wheel bearing wasn’t as easy as we had expected. Thankfully the replacement from Autovaux comes with a two-year warranty.