Thread: 3.0 TDV6/SDV6 higher mileage bearing failure theory

If you change your own oil get in habit of closely inspecting the oil filter vanes and celebrate not seeing any shiny stuff. There would be a fair warning in the changes prior to a failure I’d expect not that the solution other than selling is easy or pleasant to consider.

It has been a case of thinking that the failures are random (eg bolts working loose) and hoping that this engine is a good one. However if the cause is bearing deteriation then one would expect there to be early warning signs to some degree in every engine and therefore the filter sparkle check seems like a must-do.

This engine had a rumble on start-up the day before but became smooth once warm. While being driven the next day at 100 kph the engine lost power then the oil light came on, so the driver pulled over to let it idle for a while which seemed normally quiet, but the oi light stayed on so the engine was switched off. The crankshaft is now stuck solid and an oil sample sparkles lots.

Please, please, please tell me you're going to pop the sump off and have a good look around?

So many of these end with "it's ****ed mate" and the black box gets shunted off into the corner of a workshop somewhere to be replaced with another black box.

Heck a siezed big end would stop it turning, and given you can buy undersized shells you may get away with a new rod, crank grind and a set of shells.

Bearing cap bolts will be checked for tightness and bearing slippers will be inspected, that is certain. The ladder frame needs to be removed to access the bearing caps which requires the diff to be removed, so not a quick job with the engine still in the vehicle and only working with ramps. A vehicle has been borrowed for the time being but the D4 needs to be working again ASAP so the engine won't be rebuilt for this vehicle and possibly not rebuilt at all. A replacement engine's bearings will be replaced with Kings bearings before the swap, if an engine swap is the chosen path.

Originally Posted by Graeme

This engine had a rumble on start-up the day before but became smooth once warm. While being driven the next day at 100 kph the engine lost power then the oil light came on, so the driver pulled over to let it idle for a while which seemed normally quiet, but the oi light stayed on so the engine was switched off. The crankshaft is now stuck solid and an oil sample sparkles lots.

I'd seriously love to get my hands on an engine 20 minutes before it let go!

I realise I'm pointing out the obvious, but the info you provided here is really valuable.

It's interesting the oil light came on, so possibly the failure is allowing oil to escape somewhere instead of allowing the pressure to rise.

Unless the light came on before realised?

Does anyone know if the 3 litre actually reports oil pressure or is there just a pressure switch and temperature sensor?

I believe you fitted an oil pressure gauge to your tdv8, so I'm guessing they don't as they are similar age and tech.

I understand your comment on 2.7 vs 3.0 with the 3.0 being less reliable, it could certainly be contributing.

From my perspective, I wonder if it's also to do with WHERE in the rpm range the twin turbo 3.0 with 8 speed makes it torque, and the fact that they spend most of their life at low revs and reasonably high torque when at cruising speeds.

It would be interesting to see a computer log, or human log of oil pressure vs rpm on one of these motors.

Pump output volume vs pressure vs rpm would be good as well.

Originally Posted by Graeme

Bearing cap bolts will be checked for tightness and bearing slippers will be inspected, that is certain. The ladder frame needs to be removed to access the bearing caps which requires the diff to be removed, so not a quick job with the engine still in the vehicle and only working with ramps. A vehicle has been borrowed for the time being but the D4 needs to be working again ASAP so the engine won't be rebuilt for this vehicle and possibly not rebuilt at all. A replacement engine's bearings will be replaced with Kings bearings before the swap, if an engine swap is the chosen path.

Definitely pull the filter now and share photos

No advantage in checking the filter now as an extracted oil sample is full of metalic flecks.

The driver had just overtaken a vehicle when the engine lost power then quite a few seconds later the oil light came on. The driver pulled over and let the engine idle for a short time but switched-off the engine as the oil light was still on even though the engine seemed to be idling smoothly.
I understand that oil pressure has to be low for a number of seconds before the light will be turned on, noting that the light is not hard-wired to the pressure switch. Lots of low voltage DTCs were recorded at the time for as yet undiscovered reasons. The starter fuse was later found to be blown but that probably occurred when I attempted to start the engine on the roadside because when the fuse was subsequently replaced, the starter just groaned when briefly trying to start the engine as the crankshaft is seized solid.

The engine's pressure switch is just on/off.
This D4 has a 6-speed gbox so cruising revs aren't low.
A pressure gauge had been fitted until recently as the sender developed a significant leak so was removed and hadn't yet been replaced.

I fitted the pressure gauge to my 4.4 TDV8 because of all the 4.4 failures in UK vehicles where conjecture blamed oil dilution from many failed DPF regens leading to bearing damage, not that my L322 has a DPF.