D4 SDV6 Engine Failure

I have a 2015 Disco 4 TDV6 which seized at 66,000Km (crankshaft did not break).

I've now replaced the engine with a second hand engine (84,000Km) which is running fine, and I've added an oil pressure gauge.

I've monitored oil temperature using my Nanocom and found that the oil temperature peaks, on normal running on the highway at about 119deg.

When the oil is at full temperature, the oil pressure is around 10psi at idle (starting at around 25psi with cold oil). On the highway at 100Km/hr in 8th gear, engine speed is about 1700RPM and oil pressure is about 12-14psi when hot. This leads me to wonder if the low oil pressure at low revs is a contributing factor to premature failure. When mine died, it was when I was travelling at 100Km/hr and I put my right foot down hard to accelerate. This tends to push the crankshaft against the lower shells in the main bearings of course, and this is, apparently a known failure mechanism in a particular model of Mazda 6 (the 2 Lt MPS I think) which was cured by changing the gearing to the oil pump to speed it up and increase oil pressure (clearly not an option for the crankshaft driven pump in the Ford Lion engine).

At oil temperatures less than 100deg the oil pressure is still what I would consider to be adequate at around 20psi at 1700RPM which leads me to the question, has anyone considered fitting an external oil cooler to the engine?

I realise that there is a justifiable reason to run oil hot as, apparently, it's done to boil off impurities (diesel perhaps), but if one were to fit an external oil cooler and change the oil more often (say 7,500Km) then perhaps dilution of the oil would not be a problem.

Does anyone have any advice to offer on this idea? The obvious problem is getting an oil feed out of the engine to run to an external cooler - I was wondering if it might be possible to use the oil return from the large turbo for this.

Thanks for your thoughts.

It already has an external oil cooler in the valley as part of the oil filter. Cooled by a coolant circuit.

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Originally Posted by PerthDisco

It already has an external oil cooler in the valley as part of the oil filter. Cooled by a coolant circuit.

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They also upgraded the oil cooler with the change from the 2.7 to 3.0. There would have been a good reason for this.

A theory by a Russian TDV6 rebuilder known as “The Grandfather” is the oil delivered to the 2nd main journal gets too hot, the oil thins out too much here, and this accelerates the wear of the bearing leading to excess clearance which then causes additional flexing of the shaft at this point and snaps the crankshaft. Like repeatedly flexing a wire to break it.

He regularly strips down these engines and shows photos where the second main journal bearing has accelerated wear (but not spun).

The type of fatigue failure seen around this point lends weight to this argument - but cranks have also snapped with no evidence of bearing damage.

He is also an advocate for needing a higher viscosity oil. Interestingly Ford seem to be of a similar opinion for the F-150 with the 3.0 Powerstroke if worked hard and also recommend a higher viscosity oil (namely 5W-40 for hot climates or even 0W-40 if worked hard in cold climates).

So could be something in this theory.

The other key point, as already mentioned by LandRover time, is that thr oil gallery at this point is the same as all the others, yet this port supplies both the main bearing and the big end at the same time, plus gets an oil pulse once every 180degrees of crank rotation. So weakest point in the crank (furthest from the ends, highly loaded, and then not supplying enough oil there. LR time also mentioned thr use of 5w30, or as Christsian calls it, "5w dumbass". Not sure about that last one though, I ran close to 100,000km on penrite 5w30 c4 full synthetic with no issues at all, oil changed every 10,000km. I think at the lr specified intervals you would be doing the engine a disservice, plus also driving it hard from cold adds unnecessary stress and wear.

One thing that I think Christian got spot on - his LR4 SDV6 failure distribution chart.

https://uploads.tapatalk-cdn.com/202...f7aaec873c.jpg

Now this did make me laugh.

Hmm, as a passionate 2nd owner that took the vehicle from 88k to 230km, perhaps I'm an outlier in his chart. Passed through the "death zone." without issue. Im still glad I sold it, it was running like new when I moved it on.

Quote:

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Originally Posted by Eric SDV6SE

The other key point, as already mentioned by LandRover time, is that thr oil gallery at this point is the same as all the others, yet this port supplies both the main bearing and the big end at the same time, plus gets an oil pulse once every 180degrees of crank rotation. So weakest point in the crank (furthest from the ends, highly loaded, and then not supplying enough oil there. LR time also mentioned thr use of 5w30, or as Christsian calls it, "5w dumbass". .......

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For those of you wondering where the "special" oil is made, after intensive research I think I've tracked it down to Chateau Dumas - Google Maps

Quote:

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Originally Posted by GrahamH

I have a 2015 Disco 4 TDV6 which seized at 66,000Km (crankshaft did not break).

I've now replaced the engine with a second hand engine (84,000Km) which is running fine, and I've added an oil pressure gauge.

I've monitored oil temperature using my Nanocom and found that the oil temperature peaks, on normal running on the highway at about 119deg.

When the oil is at full temperature, the oil pressure is around 10psi at idle (starting at around 25psi with cold oil). On the highway at 100Km/hr in 8th gear, engine speed is about 1700RPM and oil pressure is about 12-14psi when hot. This leads me to wonder if the low oil pressure at low revs is a contributing factor to premature failure. When mine died, it was when I was travelling at 100Km/hr and I put my right foot down hard to accelerate. This tends to push the crankshaft against the lower shells in the main bearings of course, and this is, apparently a known failure mechanism in a particular model of Mazda 6 (the 2 Lt MPS I think) which was cured by changing the gearing to the oil pump to speed it up and increase oil pressure (clearly not an option for the crankshaft driven pump in the Ford Lion engine).

At oil temperatures less than 100deg the oil pressure is still what I would consider to be adequate at around 20psi at 1700RPM which leads me to the question, has anyone considered fitting an external oil cooler to the engine?


I realise that there is a justifiable reason to run oil hot as, apparently, it's done to boil off impurities (diesel perhaps), but if one were to fit an external oil cooler and change the oil more often (say 7,500Km) then perhaps dilution of the oil would not be a problem.

Does anyone have any advice to offer on this idea? The obvious problem is getting an oil feed out of the engine to run to an external cooler - I was wondering if it might be possible to use the oil return from the large turbo for this.

Thanks for your thoughts.

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Just thinking about this.

Is anyone familiar where the oil pressure relief valve is?
Is it integral with the oil pump and inaccessible?

We used to bump up the oil pressure of a BMC "A" and "B" series racing engine by increasing the effective length of the spring with the addition of spacer shims.

How is the oil pressure controlled in the 2.7 and 3.0 engine?
Can it be 'adjusted' in any way?

Quote:

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Originally Posted by Discodicky

How is the oil pressure controlled in the 2.7 and 3.0 engine?
Can it be 'adjusted' in any way?

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I'm sure the cold oil pressure could be increased by playing with the relief valve, but I don't think the operating temperature oil pressure gets anywhere near the relief pressure.
Between the crank, cams and piston cooling jets there's little restriction to keep the pressure up.

[QUOTE=Discodicky;3192701]Just thinking about this.



We used to bump up the oil pressure of a BMC "A" and "B" series racing engine by increasing the effective length of the spring with the addition of spacer shims.

Other way was to fit a Cooper S 5 vane pump. I am surprised the oil pressure is so low. On my Cooper S it was 55-60 PSI! Do motors now run on lower pressures? If so what is the reasoning behind this? Just interested.