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NJSS
Member Since: 06 May 2009
Location: Catherington, Hampshire.
Posts: 11057
  
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Grant-B ?
May I please ask why have you deleted the majority of your posts in this thread?
NJSS
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 17th May 2025 9:56 am |
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NJSS
Member Since: 06 May 2009
Location: Catherington, Hampshire.
Posts: 11057
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Quote:D-M Thumbs Up
Can you please recommend a 5w-50/50 low SAPS oil please?
I'm looking for high quality, rather than low price Whistle
NJSS
Is this a good idea ?
Regards
Nigel
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| 17th May 2025 11:57 am |
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Grant-B
Member Since: 02 Apr 2025
Location: West Midlands, Tamworth
Posts: 173
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NJSS wrote:Grant-B ?
May I please ask why have you deleted the majority of your posts in this thread?
NJSS
Yes, i deleted my posts throughout this whole forum... due to people whining & being negative at every possible moment... mainly due to not having read the whole posting & key critical details that could help them...
So I decided that I was thru with the whining bitching & moaning.
Stupidly, i thought that having a BSc in Engineering & Phd Doctorate in applied physics & doing my research properly would allow me to give clear, concise & valid information here.
I was wrong, stupid & an idiot in thinking people would actually read the whole posting, rather than cherry pick a line to whine about.
There you have it Sir
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| 17th May 2025 12:15 pm |
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NJSS
Member Since: 06 May 2009
Location: Catherington, Hampshire.
Posts: 11057
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Grant
I for one, and I see others appreciated your posts.
This thread was discussed with a couple of locals only last night.
Please continue to share your knowledge with us. 
Regards
Nigel
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| 17th May 2025 1:50 pm |
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Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 21023
  
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NJSS wrote:
Quote:D-M Thumbs Up
Can you please recommend a 5w-50/50 low SAPS oil please?
I'm looking for high quality, rather than low price Whistle
NJSS
Is this a good idea ?
Regards
Nigel
I don't think so. What evidence is there that a 50 oil will lubricate properly, and isn't too thick to flow to critical areas? My D3 Build Thread
TDV8 Retrofit Build Thread
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| 17th May 2025 2:51 pm |
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NJSS
Member Since: 06 May 2009
Location: Catherington, Hampshire.
Posts: 11057
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Thanks D-M
Would you recommend 5w40 or should we stick to 5w30 ?
I tend to change oil & filter every 6k miles.
NJSS
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| 17th May 2025 3:06 pm |
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Moo
D3 Decade
Member Since: 13 Aug 2010
Location: UK
Posts: 15082
 
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With a know issue of weak cranks, I wonder why LR didn’t issue a TSB recommending a heavier oil if this would have reduced the likelihood of crank issues etc. It’s a very cheap and simple solution.  D4 HSE EU6 (Known as Jeeves)
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05 S manual owned from March 2005
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Still original injectors and turbo
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BAS Remap, Allisport Intercooler and deCat
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| 17th May 2025 4:15 pm |
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jonno1
Member Since: 16 Jun 2010
Location: SW London
Posts: 736
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Perhaps because JLR didn't consider a different viscosity to be a solution. I'm sure that there are plenty go high mileage Discos using the specified oil.
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| 17th May 2025 5:07 pm |
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Grant-B
Member Since: 02 Apr 2025
Location: West Midlands, Tamworth
Posts: 173
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Weak Cranks -
No they are not weak.
the issue of snapping cranks is several fold...
The oil pump is at the front of the engine.
The oil gallery's run front he front of the engine.
We know that the oil pressure "usually" falls off when these engines hit 110k miles or more
Potentially the pressure drops down to 2 0r 3psi at tick-over & only up to 25 or 20psi at 3000 rpm - which is tragic at the very least..
So, the oil will escape readily from bearings with lots of clearance & wear... this then starves the other bearings - a lot.... and exponentially adds wear, more heat, more bearing clearance etc.
5w30 oil means a few things & is used for a few reasons.
1st.. thinner oil gets better mpg, less emissions & better figures to show off to customers.
A vehicle that has done 100k miles, Landrover do not give a sh*t about because they already have their money.
so
the 5w of the 5w30.... the 5 is the thickness/viscosity on cold starts/winter/cold climates WHEN THE OIL IS COLD.
It is nice & thin, so it gets where it needs to go & lube the engine components from cold.
the 30- bit of 5w30 is all about how this the oil is when at running temperature.
Note that engine oil temps have to come with friction/sheering/pressure/cooling & rapid heating again & again.
Engine oil temperatures generally operate from 200 > 230'C... the oil is tortured.
At this temperature, th 3w30 oil ends up water thin as far as the engine is concerned.
so, having a compatible oil that maintains the 5w thickness is essential.
The oil I mentioned holds its 5w cold thickness thru the temperature range & keeps the oil pressure at a tolerable level.
**Going back to Weak Cranks.
with low oil pressure, the main & big end bearings will unevenly wear...
this main bearing wear potentially causes the crank-shaft to not sit in the main bearing shells evenly.... we are talking 5 decimal places of a mm here or smaller...
This uneven levelling of the crank can cause micro stress fractures over time in the crank shaft.
THEN
we have a new issue to also contend with.
These engine develop huge power at low revs, also when the oil pressure is at its lowest...
force & lack of oil causes immense heat & can BOIL the oil in the bearing journals.
An already stressed crank, with low/almost zero oil pressure, heat and partial welding of the bearings is simply begging for a partial seizure of a big end bearing in the con-rod, and this will fracture & split the crank...
Now back to OIL.
The 5w30 is water this at high temperature.
The 5w50 maintains the 5w viscosity at high temperatures & keeps the oil pressure up.
More oil pressure = less friction.
We already know the oil is a 5w variant, & the 50 prevents/reduces the high temperature dilution of oil pressure.
This in turn reduces valve lift hot tapping issues, big end & cam noise etc... don to having oil pressure to get the oil where it needs to be.
NOTE -the chemicals & additives in the oil ALSO have to be correct to ensure the DPF & Cats survive & the engine does not fill with sludge.
Hope this helps -
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| 17th May 2025 6:27 pm |
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Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 21023
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The oil thickness is critical when cold. Why is it not critical when hot?
5w30/5w40 is good for temps down to -30 degrees, whereas a 10w40 and even a 10w30 is good for temps of -25, more than adequate for our country/climate. If a thicker oil = better, and most engine damage occurs on cold starts, why not a 10w** oil? My D3 Build Thread
TDV8 Retrofit Build Thread
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| 17th May 2025 6:34 pm |
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Grant-B
Member Since: 02 Apr 2025
Location: West Midlands, Tamworth
Posts: 173
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JLR must have decided that 5w30 was adequate... which it would be for a new engine.
The primary issue on a cold start it to get the oil to the bearings instantly...
10w30 is twice the viscosity vompared for 5w30, so maybe it didnt move fast enough...
Also a thinner oil when cold is less likely to be driven through the piston rings & soot up the DPF...A WHOLE HOST of teasons i guess.
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| 17th May 2025 7:56 pm |
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faulksy
Member Since: 24 Dec 2023
Location: powys
Posts: 441
 
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i wondered why grant deleted his posts, now i know.
im interested like others have said. keep it coming grant had a d1 ,d2 a land mark d4 for 3 days now have awsome d4 in orkney grey hse sdv6 my12
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| 18th May 2025 9:08 am |
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Grant-B
Member Since: 02 Apr 2025
Location: West Midlands, Tamworth
Posts: 173
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How do you know that a 40 or 50 oil moves fast enough when hot?
Simples...
30 years of work with companies like JLR, ZF & McLaren, Porsche & Mercedes...
Mostly Engine developments, Chassis & performance handling..
I am an engineering contractor & get hired to solve problems.
Re these oils...
5w30 is fine with a tight new engine, but even so.. 3w40 would be better, but it isnt so good for the selling figures & numbers to make the vehicle sound so good re emissions & economy.
However,
The charachteristics of an engine CHANGE the more miles on her.
By simple trial & error, we know that 5w30 on an engine in mid life will rattle due to wear & loose tolerances.
We also know that 5w30 oil is fine in an older cold engine but rattles like hell when even slightly warmed up..
5w40 keeps the rattles away until the oil temp reaches 130 degrees approx
5w50 keeps the rattles reduced until about 195>215 degrees.
Where the knowledege comes in & having the viscosity testing kit available is handy and 30 years involved with this malarkey becomes useful.
5w60 oil starts breaking the rules, because although the oil is 5w, it is thicker by default, as the additives & agents in the oil are by default thicker when cold, meaning that even thogh a 5w60 oil is thinner when cold, it transitions to holding viscosity at a lower mid range temperature... so unless you are on a race track
& really hitting the throttle hard ALL THE TIME the 5w60 will potentially cause flow issues.
Added to all of the above...
Oil pressure is the key issue in an older rattley engine...
Thin oil  out of the bearing gaps & causes wear, this partial seizures & snapped cranks.
Re the DPF issues...
Regardless of the sap levels in the oil, ideally a low sap oil is desirable, but weighed up against the shear amount of oil vapor that is burned from crank case venting, it becomes almost irrelavent provided you drive hard occasionally to clear the DPF..
But again a LOW sap oil is best...... as a thicker cooler oil will drastically reduce crank case venting of oil vapour to be sucked into induction & burned & thrown out of the exhaust thru the DPF screen..
At the end of the day, it is your engine, & you do as you please with it.
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| 18th May 2025 9:15 am |
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