Thank you, Craig,

Your explanation was not only clear to understand, but also sufficiently through to convince. I will go ahead with what advised by Doug and you, thank you.

At the same time, it sparked an interest in oils. This conversation may well have been discussed in other threads so, please, feel free to move this post (not thread) under a more appropriate thread.

A few follow up questions for mere interest in the subject, from someone who has never studied oils:

1. I understand why the lower the winter number is, the better, in principle. But, is there not a point where there are diminishing marginal returns (marginal viscosity increase, becomes lesser and lesser)?
a) can oils ​​​​​​ not reach bearings, etc sufficiently quickly, already with a 5W or even 10W viscosity, that the price increase, for 0W oils, is not justified?
b) were Engines' metals (bearings, scrapers, mains, etc) & design in the 1960 not engineered to use much lower winter viscosities? Today manufacturers cut corners to save costs (re materials & build quality) and hence the need to develop better winter viscosities?

2. Do you agree with Doug that, besides only the zinc additive, there are no counter recommendations in using modern oils (not only engine oil)? In the official Rolls-Royce forum the consensus (which does not mean it's correct or right) is that some modern oils contain additives that can damage some parts (I don't remember if it was the O rings or gaskets or pipes or ... )

3. I will use this car only in Italy, only in summer, and only for holiday transfers (long [6 hours] and fast [140Km/h]). Temperatures easily reach 40°C in summer and I fin drive for very long stretches at full legal speed. Would a thicker engine (50) not be preferable?

-------------------

As an aside comment, I was reading the spec sheets of these three brands and the difference in viscosity is less than 20 points on 1,300 plus (about 0.01%) when cold, and a little more when hot (but still less than 1%). I presume that this is because they are all very good brands (Doug's comment). However, I read somewhere that while the are all called fully synthetic, none really are.

Tommaso

PS: the exit contributors really make this forum incredibly useful. Thank you.

 

For a summer car, a 5W would be just as good as a 0W. It's when temperatures get cooler that you get the real advantages of 0W. I used to have a 1964 E Type and when the temperatures went down to about 10°C it was noticeably slower to crank with 20W50. I changed to 0W40 and it started and cranked faster.

The clearances are much tighter in a modern engine, mainly because of CNC machining, the tolerances can be much more consistent than they were in the 1960's. That means a lower viscosity oil can be used, because the leakage rate form the bearings can be controlled to a much greater degree. That's why we are seeing oils as light as 0w16 today. An engine built to 1950's tolerances wouldn't work on that light an oil. It's also for fuel economy, a light oil takes less energy to pump and creates less heat. Is it easier to pour water or treacle? Car makers are doing everything they can to improve fuel economy and lower emissions. I wouldn't really call a V12 modern, but that's why I wouldn't suggest using 0w20 in it either.

As long as you have sufficient oil pressure, you're good. Many people think that more pressure = better, but that's not the case. Flow is what is important to the bearings, and high pressure means lots of resistance to flow. Think of a garden hose that is kinked - lots of pressure, but no water comes out. As long as you have sufficient pressure to lift the crankshaft off the bearings, that is sufficient. In the V12 that can be as little as 5 psi at idle - it doesn't take much.

I don't know enough to say that additives would damage an engine, but I'd be very surprised if that was the case. The zinc was removed because of it poisoning the catalyst. There are other additives that prevent scuffing ( which is what the Zinc was there to prevent). As long as the oil film is of sufficient thickness, you'll never need the insurance those additives provide.

Fast highway driving driving wouldn't need a heavy oil. You have sufficient revs at that speed that the oil is flowing nicely, you'll have good oil pressure and there is plenty of air going past the oil pan for cooling. It's easy on the oil. If you were running a taxi in Rome in the summer than might be a different story, where it's hot, low RPM meaning low oil pressure and lots of idling with little to no air flow for cooling.

Were you looking at kinematic viscosity on the spec sheets? There is a range they must fall into to be called a particular grade, so I'm not surprised there is little difference - that's the way it should be.
There are different types of synthetics, from highly refined mineral oil basestock to PAO basestocks. Still synthetic, just different kinds withing a broad group.

 

Once more, thank you, Craig!

Apologies, this is unclear. Doug was recommending to use zinc substitute additives but, if I understand correctly, you seem to feel that they are superfluous.

So for a car used mainly in summer you would actually prefer 0W40 rather than 0W50?

cSt

-----------------

I am doing a lot of work, and the oil pan is coming off (new oil pump). I was advised to flush the oil circuit by first running a cheaper oil for a few hours, and then re-flushing, and re-filling with Castrol. Do you think that it's a waste of time/money?

Using this https://operatingfluids.mercedes-ben...sheet/229.5/en reference, I then found 20 litres of Castrol 0W40 relatively cheap at €8.4/Lt but in a 20Lt container https://vieffelubrificanti.com/produ...a3-b4-20-litri Since I do only 3,000Km/year I change oil every 2 years. Will oil keep for 2 years? If not, I found 12LT at €11.6/Lt https://www.crclubrificanti.it/lubri...1/192-pezzi-12

.

 

I'm not clear on the exact details, but I have been told by those who do know that there are additives in modern oils that eliminate the need for zinc.

Correct, I would prefer a 0w40 over 0w50. Partly because it's less of a stretch on the viscosity improvers to only go to 40 vs 50.

It wouldn't hurt to run a conventional oil for a while and then do an oil and filter change. Probably not necessary, but if it makes feel good, do it. Or fill with synthetic, drive for 500-1,000km and just do a filter change and top up the level.

The good practice is to change at least once a year no matter the mileage. New oil kept in a sealed container will last a year. If I had a choice, I wouldn't go 2 years between changes.

 

Good morning,

I found a few useful maintenance and driver handbooks online.

Below are extracts from a 1987 maintenance handbook for series III (both engines).

I hope that these can help. Happy to offer more images if it can help others.

 

Good afternoon, I was advised to ask my mechanic to check:

• the air extraction pipe, that can get blocked up, and won't suck out the air from the system. It should be a pipe near the orange Marelli box. Can anyone send me a photo, as I cannot locate it?
• the fluid return pipe that brings cooling fluid back into the expansion tank, when it cools down. It should lead to (or from) the atmospheric recovery bottle. Again, please, a photo of the pipe?

Thank you! Tommaso

 

Regarding the “air extraction pipe” being near the orange Marelli box….well, the V12 in the Series III saloon (and that includes the last 1992 models) never used the Marelli ignition - so you won’t find any orange box! However, the same engine in the late XJS did use the Marelli.

 

Yes, you are correct. My mistake. This advice was given by an XJS expert who advised me to check this now that I have a completely new NAR cooling system.

Can you help me identify where they are? Maybe with photos, please?

 

Update: Monday I will inspect the progress on the Double Six, that I have not seen in six months! Wish me luck! I will update on the progress. Smiles, Tommaso

 

I think he means the radiator purge system, part of which is the thin pipe that runs along the radiator top panel. Nothing to do with the ignition system, but he means on Marelli cars this pipe is just forward of the marelli amps which are also on the top panel.

 

Greg, good afternoon, tomorrow morning I will see the Daimler! Kindly, would you, please, highlight or indicate on a photo, the the two areas mentioned by Andrew Harvey, now that we understand that the reference to the Marelli is wrong?

• the air extraction pipe, that can get blocked up, and won't suck out the air from the system. It should be a pipe near the orange Marelli box. Can anyone send me a photo, as I cannot locate it?
• the fluid return pipe that brings cooling fluid back into the expansion tank, when it cools down. It should lead to (or from) the atmospheric recovery bottle. Again, please, a photo of the pipe?

 

Tommaso
I amnot familiar with the V12 Saloon cooling system. It may be that it is different from the XJS. SO I am a bit confused. If you require info about the XJS here it is:
This pipe along the radiator top closing panel:




Atmospheric tank info:
Pipe by the clip numbered 6 in this diagram
https://parts.jaguarlandroverclassic.../brand/jaguar/
is the pipe numbered 3 in this one
https://parts.jaguarlandroverclassic.../brand/jaguar/

It leads from the overflow chamber in the top of the header tank fill spout to the atmospheric recovery tank in the first diagram. This pipe must be quite strong to resist atmospheric pressure as it allows air to be sucked back into the header tank from the atmospheric recovery tank as coolant cools down. It allows coolant expansion to be kept in the atmospheric tank. This is the pipe that must not be blocked. On an XJS the atmospheric tank is in the cavity behind the LHS wheelarch behind the stone shield.

The Marelli amps are also on the radiator top panel, just in the middle behind the pipe. This photo marked up shows where they would be:

Blue boxes show where Marelli amps go

Pic of the real thing from a forum member's immaculate car!

 

Wow, thank you. Tomorrow I'll try to identify said systems from these photos.

Thanks Greg

 

The recovery bottle in in the left front fender, if front of the wheel. There is a hose that goes from that to the pressurized expansion tank, which is bolted to the fender inside the engine bay on the left side. It's the one with the radiator cap on it. To see the hose from the pressurized expansion tank to the atmospheric recovery tank you'd need to remove the left front wheel.

 

I am still not clear if you seek info on your DD6 saloon or an XJS.
The saloon equivalents of the diagrams are here:
https://parts.jaguarlandroverclassic.../brand/jaguar/

Note that ALL Series 111 saloons have Lucas ignition, so you will not see any Marelli amps on the radiator top panel.

 

@ Greg and @Jagboy64
Thank you, yes, my mechanic had already removed those parts as he had imagined that they could become blocked. Thank you for helping!

@Greg
1992 Daimler Double Six - on the other thread I'm considering purchasing an XJS

Today I visited the garage, this is the old lady:


... we were discussing further work:

1. Remove front subframe, swap dampers & worn bushings (labour €400)
   1. this would also allow to drop the engine to change a seal between the flywheel and gearbox. He could do it without dropping the engine, but if he were to drop it, we could sand the valve covers, restore the metal and make the engine bay look fresh again:
2. Replace both front rotors (labout €50)
3. Remove both fuel tanks, to ensure that there is no rust, replace fuel lines and filters (€300)
4. I am considering to respray the Double Six. In a few points the chrome runners have come loose and superficial rust is showing where the clips held the runner. The bottom is rock solid without any trace of rust. But under the paint there are areas with filler and the paint, itself, is not at its best. I asked for a respray estimate with three layers of laquer. Next week,

 

I don't think lacquer paint has been available for decades. Even if it was, I wouldn't use it, as it can be prone to cracking over time. GM cars used to be notorious for this. I would use a quality base/clearcoat now. Although talking to your painter is important, as you want a refinish system that he is familiar with and skilled in using.

 

Apologies! My command of the English language doesn't match my passion for these cats! Of course I intended clear coat, not lacquer. Apologies

 

@ all you who helped, thank you. Please, for the benefit of future readers, improve this list, checking quantity, specs and manufacturers.

-----------------------------

• Engine oil
  • QTY: 10 Lt
  • Specs :
    • Hot climate: 10W50
    • Cold climate: 5W40
    • If you can find/afford them, then 5W50 (hot climate) and 0W40 (cold climate) are even better
    • Notes: (*)1 and (*)2
  • Manufacturer: only main manufacturers who actually refine the oil such as Shell, Chevron,Total, Mobil, Castrol, etc
• Brake oil
  • QTY: 1 Lt to 2 Lt (depends on how well the flush goes, and how much air is in the system)
  • Specs: J1703 DOT 3 or DOT4
  • Manuf: ANY
• Transmission oil
  • QTY 3 Lt to 4 Lt (about 1/3 of the total fluid: pan only can be drained; torque converter doesn't have a drain
  • Specs: Dexron 2D (Dexron VI is backwards compatible)
  • Manuf: Dexron or Mercon
• Rear differential oil (w/ power lock)
  • QTY: 1.5 Lt
  • Specs: 90 + limited slip additive - any gear oil formulated for limited slip diffs
  • Manuf: ANY
• Power Assisted Steering oil
  • QTY: 1.2 Lt
  • Specs: Type F ATF
  • Manuf: Dexron or Mercon
• Cooling system liquid:
  • QTY: 10 Lt or 5 Lt (depends if block can be drained = 10 Lt; if only radiator = 5 Lt)
  • Specs: Green type - Ethylene glycol diluted @ 55%
  • Manuf: ANY
• Air filter
  • QTY: 1
  • Specs: ANY
  • Manuf: ANY
• Oil Filter (I read best only OEM as others cavitate?)
  • QTY: 1
  • Specs: only OEM [EBC9658] or a Mann. Nothing else.
  • Manuf: Jaguar or Mann
• Fuel filters
  • QTY: 2
  • Specs: ANY
  • Manuf: ANY
• Spark Plugs
  • QTY: 12
  • Specs: BPR7 ES
  • Manuf: NGK
• Rear axle
  • QTY: 1/2 Lt
  • Spec: axle grease (follow garage manual for 10 points grease)
  • Manuf: ANY

-----------------------------------
(*)1 Jagboy (Craig) recommends 5W40 also in warm climates
(*)2 Jagboy (Craig) recommends only "APPROVED" against Mercedes Benz 229.5 (NOT "meets" the requirements of)

Below: Jaguar/Daimler Series III maintenance handbook 5M/12/84

 

Hi all,

I am struggling to find an MB 229.5 approved oil, with summer grade 50, on sale in Europe. So far I only found Mobil 1 Racing 0W-50 or MB 229.3 approved oil with a ?W-50 rating.

While all oil manufacturers (Shell, Mobil, Castrol, Total, Chevron, Motul, etc) recommend 0W-40 (but only some MB 229.5 approved) when I select for my motorcar manufacturer and model, the official 1984 Jaguar maintenance handbook clearly shows differently, recommending higher grades for use in higher climates.

My fear persons our extremely high average temperatures that usually range in the 40s°C (reaching 44°C for a whole week last year) and very long ques in traffic, around our summer house (by Santojanni island on the coast of Calabria), when I definitely want to keep my A/C running while in traffic.




I am considering:

1. Mobil 1 Racing™ 0W-50 (*)3
2. MB 229.3 approved ?W-50 oils
3. MB 229.5 0W-40 oil

(*)3 Even if this racing oil damages my catalytic converters I am not too concerned because: (i) classics are not as stringently inspected for CO emissions and (ii) I do not believe in this climate superstition madness (with all due respect, and love, for those who do believe in it), so I would not mind removing the catalytic converters all together, or letting them become inefficient.

Any advice? Thank you in advance for your time and expertise.

Tommaso

PS: what's the difference between MB 229.5 and MB 229.3 ?