Thread: Why do 2.7 cranks break?

Originally Posted by DiscoDB

So it is the 3.0 that LR change oil spec to the low HT/HS viscosity oil - namely C1 like Jaguar. Whereas Citroen stuck with C3 for the 3.0.

Makes me think there is more to this oil spec theory.

So for the Ford F-150, Ford changed the oil spec again for the 3.0 going now to an ACEA E6 oil which has the same higher HT/HS viscosity as the C3 oil which Citroen still specify for the 3.0 to this day.

What that tells me is for the 3.0 JLR went to the lower HT/HS oil viscosity to reduce fuel consumption whilst Citroen and then later Ford US stuck with the higher HT/HS viscosity oil to chase better wear protection and durability.

Make me wonder if any 2.7’s were getting serviced with the lower HT/HS viscosity oil given this is what Jaguar specified for the 2.7. If I was an owner of a 3.0 I would be inclined to follow the Citroen preferred oil for the 3.0.

Originally Posted by PerthDisco

I also don’t believe an injector could fail bad enough to dilute oil and not give a code or fault. You’d see elevated oil levels also with enough diesel to contaminate it.

I agree - and correlation does not mean causation. Just an interesting observation - especially the one from Oval Autos and let’s be honest, plenty of people do continue to drive vehicles even if they are giving fault codes or making unusual noises/vibrations.

In 2019 alone Oval Autos scrapped 40 TDV6 engines so they see plenty of them. I believe this included both 2.7 and 3.0. 15 had snapped cranks, and 25 had damaged cranks that could not be repaired.

To say that 9/10 engine failures they see also had injector problems is an interesting tell-tale. And to have a second repairer make the same observation is not to be ignored even if it is just a coincidence.

Originally Posted by josh.huber

Just my view, injectors won't directly "cause" the failure, however again just me.. The engine doesn't seem to be able to cope with vibration. So a miss fire or power imbalance, or the torque converter shudder would cause issues in my mind to these specific V6 diesels .

In addition the small balancer on the front of the crank, the TDV6 also gets an additional balancer fitted to the auto.

One of the theories I recall reading is transmission induced vibrations are more likely with the LR compared to the 2WD sedans which use the same motor.

Supports your comment that these engines don’t cope well with any harmonic imbalance.

Originally Posted by rick130

I think what may be happening with these engines, and it's only a guess, I'm not familiar with them, is that the more viscous oil its creating too much drag between the shell and journal leading to the spun shell, (and then a lube failure as the oil feed hole has been 'lost') unlike a 'normal' spun bearing failure where the hydrodynamic and then boundary layer lubrication has broken down (oil breakdown, too much clearance, etc.) and that leads to a metal to metal situation.

For an alternative view, Rick130 felt higher viscosity could lead to higher drag and this is what spins the bearing shell.

Would explain why LR tried a lower friction oil.

Originally Posted by DiscoDB

In addition the small balancer on the front of the crank, the TDV6 also gets an additional balancer fitted to the auto.

One of the theories I recall reading is transmission induced vibrations are more likely with the LR compared to the 2WD sedans which use the same motor.

Supports your comment that these engines don’t cope well with any harmonic imbalance.

Going back to the root cause topic do we agree that it seems cranks just don’t snap on their own. It seems to me that they sometimes snap after the bearing shells develop wear and sometimes those shell/s bind and rotate blocking oil flow and sometimes this leads to a seizure usually at one of the centre shells snapping the crank in a common position?

Because if that’s the case then some oil related issue stacks up.

On the other hand has a snapped crank been seen with perfect bearings?

If cranks snap with perfect bearing shells then some imbalance, lash. pulse, casting or hardening issue stacks up.

The former may be 90% and the latter 10% is my sense.

The Russian video also mentions the updated oil pump was bigger in capacity and he provided oil pressure specs.

It’s why I’m keen to see Outback Discovery’s engine bearings in this old TDV6 with original pump that failed on the timing belt tensioner to destroy the engine.

Originally Posted by DiscoDB

That is the alternative oil recommendation by Penrite for the Territory.

Actually it is their recommendation for terry’s once out of warranty

Originally Posted by incisor

Actually it is their recommendation for terry’s once out of warranty

The plot thickens.

Originally Posted by DiscoDB

In addition the small balancer on the front of the crank, the TDV6 also gets an additional balancer fitted to the auto.

One of the theories I recall reading is transmission induced vibrations are more likely with the LR compared to the 2WD sedans which use the same motor.

Supports your comment that these engines don’t cope well with any harmonic imbalance.

The 2.7 would be more likely to see the trans shudders through the crank, they were the crowd that learnt the hard way and spread the news about Auto servicing. I wonder how many D3 got driven with a tc shudder until the crank died??