Engine Oil

[newbieUK]

I'm interested in hearing what you guys are pouring into the heart of you beast.

Ever since having the engine replaced (porus block) with a top hat linered block I've been using fully synthetic Mobil 1 0-40w, but have always had a slight leak from somewhere, no big deal, loosing about a litre for every oil change (10,000 miles).

I was wondering if I used a thicker oil say 10-50 would this help to decrease the leak, but could I get this as a fully

sythethic oil, or would this need to be a semi ??

Anyhow, feedback would be appreciated as the oil service is now due (next weekend probably) and at the same time I was going to swap out the sump gasket, incidentally has anyone swapped one out and is it a straight forward enough job ?

Should of mentioned the engine has done 26,000 mile since the transplant without any real hiccups so I have no real concerns over the Mobil 1 stuff, but I have read the dirty big V8 likes thicker blood.

[SteveRK]

My understanding is that oils whether synthetic or not will more or less be the same viscosity 'thin' when hot, its just that the synthetic remains 'thinner' when cold than conventional oils - therefore changing to a different type of oil would make no difference - unless it only leaks when the engine is cold of course.

I have Mobil 1 fully synthetic in my car (Diesel Mercedes) and with the onboard service interval computer i regularly get 18,000 miles between oil changes. Mind you it costs me £110 for the oil as it takes shed loads.

Most people really rate Mobil 1 and i would suggest the the original manufacturers oil change intervals could be extended when using this type of oil??????????

[paintman]

You are probably burning it.

There has been much discussion over the years on all LR forums about oil & the V8.

Full synthetics are not recommended for the old technology of the V8.

Frequent oil changes seem to be the key, the LR suggestion of 6000 is too long & many, me included, opt for 3 to 4000.

I have used Castrol 15w-40 for many years without incident.

[newbieUK]

My understanding is that oils whether synthetic or not will more or less be the same viscosity 'thin' when hot, its just that the synthetic remains 'thinner' when cold than conventional oils - therefore changing to a different type of oil would make no difference - unless it only leaks when the engine is cold of course.

I have Mobil 1 fully synthetic in my car (Diesel Mercedes) and with the onboard service interval computer i regularly get 18,000 miles between oil changes. Mind you it costs me £110 for the oil as it takes shed loads.

Most people really rate Mobil 1 and i would suggest the the original manufacturers oil change intervals could be extended when using this type of oil??????????

thanks for the speedy response Steve, in that case I'll be sticking to the Mobil as living in rural north scotland we had wide spread ground frost just this week.

It'll be intersting to find out what others are using

[newbieUK]

You are probably burning it.

There has been much discussion over the years on all LR forums about oil & the V8.

Full synthetics are not recommended for the old technology of the V8.

Frequent oil changes seem to be the key, the LR suggestion of 6000 is too long & many, me included, opt for 3 to 4000.

I have used Castrol 15w-40 for many years without incident.

Cheers Paintman,

I don't know if this has any bearing on things, but I should of mentioned that the car is a 4.6 (thor) and used as my daily car averaging approx 75-80 miles/day

[Hybrid_From_Hell]

Er NO

You wnat a qulaity Oil for an engine with its roots in the 50s, and that not a thin syntheiec.

I run mine on Valvoline VR1 racing 20/50 oil.

Ian G (BBC) ran his on Magnatec 10/40W and then tried VR1 and has stuck with it

A Rover V8 needs an oil with a decent thickness - 20/50 and a stickability - often thought of as syntheic - except they are too thin as they are really more suited to Modern engines, the VR1 behaves as such its the oil used by many top V8 builders, inc JED

Using to thin an oil (even if synthetic) wil see oil pressure drop, rattles on start up and heavy wear.

Go buy and new filter and some VR1 - quickly

Nige

[davie]

hey there - sorry no useful stuff here just a welcome to forum. Nice to see another member in area, i am out in banchory so pretty close to aberdeen.

[FridgeFreezer]

Mine is a 4.6 and I use Comma 20W50 (it's reasonable quality and cheap) or Castrol GTX 15W40 if I'm feeling flush

0W40 is waaaaaay too thin, your engine is not designed for that type of oil. No surprise it's going missing. I once made the mistake of using 5W40 or such like in my 3.9, it lost oil pressure on a hill climb and would not re-prime until it had cooled down and we'd stuck a load of thicker cheap oil in.

The RV8 likes thick oil, and having it and the filter changed often. Sticking fancy-pants oil in will not only be bad for the engine but because Mobil costs about a million pound you're less inclined to drop it every 5k miles and replace it. Comma 20W50 costs about 1/4 so you can change it 4 times more often

[JimAttrill]

Redline makes oils in just about any viscosity up to sae70. Some of these oils are used by the 'fuel' drag racing fraternity and have the advantage that they can be boiled to evaporate the alcohol or whatever! These oils are not cheap at all, but are 'true' synthetics unlike some refined minerals which masquerade as such.

As I have a 300Tdi I am not using expensive synthetics but change the (good quality) mineral oil at 3000 miles. I do, however, use their MTL in the R380 and it gives a magnificent gear change.

[newbieUK]

thanks guys.

I'll take your advice and opt for the 20-50 (probably the VR1 stuff) as the last thing i want is to have to replace the engine again.

Next 3 questions then,

1.How does using the thicker oil effect cold starting performance seen as in winter it can easily get down to minus 10 where we live ?

2.Does anyone know where to get the VR1 cheaply either in Aberdeenshire or mail order,

3. Does anyone want to buy 8l of mobil 1 .....only joking I'll stick it in my other car !

[Hybrid_From_Hell]

1. Just start and let the engine warm up with low revs should be fine

2. Er No

3. Er No squared

Nige

[steve_d]

Mobil 1 is an excellent oil but all wrong for an LR V8.

The Comma oil is more likely available local to you and will work fine.

I use Mobil 1 in my other V8 (Chevy) but use 15W50. I use the synth there because it is making 508hp.

Steve

[q-rover]

I use 5W-50 in my 4.6

There is no difference in viscosity between a synthetic, semi-syn, or mineral.

They will all be 5W-50, 10W-40, 20W-50, etc

Mineral oils are left over products from refining crude oil, with additives.

Synthetic oils are usually made from the by-products of cleaning/ refining gas.

This means the base product is much cleaner and better quality, which means it can be synthesizd better

and have it's performance tweeked to suit it's application better than mineral as the molecular strings

are longer.

FUnnily enough, engine oil doesn't get thinner as it heats up it gets thicker.

The first number refers to the relative viscosity when the oil is cold (40°C) the 2nd number

is an indication of its relative viscosity when warm (100°C).

So for the V8 you need something that is quite liquid to start so it can be pumped around

the engine quickly, but then needs to become quite thick to give protection and lubrication

as the tolerances aren't the best in the V8. So something like 5W/ 15W/ 20W-50.

Now the advantage synthetics have over other oils is that because the molecular strings have been

manipulated and the base product is of high quality it has better performance and is able to resist

degrading and tolerate higher temperatures better than ordinary mineral oil.

However consider the fact that you actually want to change the oil BEFORE it degrades to maintain

engine protection. So even though I use 5W-50 fully synthetic oil I still try to change it every 5000Km.

Also make sure the oil conorms to the relevant API standard. Usually small print on the back, as this will

give you a better indication of quality than just the viscosity rating.

[David Sparkes]

FUnnily enough, engine oil doesn't get thinner as it heats up it gets thicker.

Really?

I hope I haven't taken that quote out of context.

However, perhaps you can give some supporting comments, because while we know oils CAN get thicker with heat (cue the transmission Viscous Coupling) my own experience with engine oils leads me to believe they get thinner as the heat rises.

They certainly seem to pour more easily during warm weather (say 15C), compared to cold weather (say 0C).

You mention "relative viscosity".

Relative to what?

It's own viscosity at another temperature, or against an external 'reference' viscosity, of another liquid at some specified temperature?

Thanks.

From another post:

"1.How does using the thicker oil effect cold starting performance seen as in winter it can easily get down to minus 10 where we live ?"

I don't think this question has been answered.

It's not about how to use the engine once it's started, it's about the additional work the starter system has to achieve to turn the engine over with the additional drag of 'cold and thick' oil.

Cheers.

[Bowie69]

This is the whole reason for multigrade oils.....

When cold, a multigrade oil acts like it is the lower of the two figures, ie the 20 in 20w50, and 50 when it is hot, the higher number being the thicker oil.

As the oil heats up the some of the polymer molecules (that are added to make an oil multigrade) expand making the oil act as if is was thicker when hotter, although as it is warmer, it appears thinner. the CHARACTERISTICS of the warm oil is of a 50 weight oil, where as the the cold oil is like a 20 weight.

So.... you get thin a characteristic oil in the morning when cold to allow easier starting, and a thicker oil when hot to maintain oil pressure.

It removes the need to run 30w oil in winter and then change to 50w oil in summer when things are a lot warmer.

You can read a bit more here: http://en.wikipedia.org/wiki/Engine_oil#Multi-grade

HTH,

[q-rover]

A slightly better explanation, thankyou.

These polymer chains are what start breaking down when you use the oil in an engine.

With a mineral oil it happens straight away, but because a synthetic oil is made from

higher quality base products it is able to resist this breakdown for longer, but it will

break down eventually.

Therefor a synthetic oil will give your engine better lubrication over a longer period, but you

should not think that you can stop changing oil because of that reason.

Like I said before, oil needs to be changed before it's properties start to degrade to continue

to give your engine proper protection and lubrication.