Another 95 AJ16 owner here...
I am in Houston and use Mobil 1 High Mileage 10w40 year round. I love it. Change it every 5k miles. I have tried lots of filters but have found that whenever I use the genuine Jaguar filter the old oil comes out a lot lighter than if I use another kind, so I stick to Jaguar filters.

I see you also have the same Alpine Head-unit I have. I love mine, but I am thinking they will be coming out with a single din Applecarplay unit pretty soon, which I will be all over !

 

It's all about this:

ZDDP. Zinc dialyldithiophosphate

Short version of the story is that ZDDP is one of the things that makes motor oil a good lubricant. A dozen or so years ago oil producers starting putting less of it in motor oil because it can damage cat converters.

The real world significance of this reduction in ZDDP is often argued, sometimes hotly. It appears that the old 'flat tappet' engines might be susceptible to damage due to the less-lubricating ability of newer oils.

Some motor oils still have decent amounts of ZDDP. You have to research to find 'em. Or, you can easily buy little bottles of ZDDP to add to your oil.

That's it, in a nutshell.

Millions of pages of debate out there on the internet.

Cheers
DD

 

To clarify, I said I use whatever name brand is on sale or NAPA house brand. That may or may not be the same as your idea of 'the cheapest oil' and I certainly would never recommend only 5 oil changes in 300,000 miles!


Cheers
DD

 

I usually need to top up 1-2 quarters in between oil changes. Dont see it leaking so assume general consumption. Do you guys have similar experience?

 

If you are interested in ZDDP, archoil makes an alternative to it that doesn't mess up cats like ZDDP does

 

FWIW

My AJ16 engine ...about 165,000 on the clock....uses 1 quart/4000 miles.

Cheers
DD

 

I'd always heard ZDDP was removed from motor oil not because it was potentially damaging to the catastrophic converters, but because it was potentially (or known to be) carcinogenic - that the engine oil system wasn't technically "sealed," and therefore potentially hazardous. They did still use ZDDP in gear oil even after they'd discontinued its use in motor oil, right? I sure wasn't aware you could still get the stuff!

I just added a quart today. I thought it was peculiar after only a thousand miles (on an engine that just rolled over 88,000 yesterday) but I'm not going to get too concerned cos when I checked the oil before pulling the trigger on the car, it was a cold engine. I checked it today shortly after a run. I'll keep an eye on it.

 

I wouldn't recommend 5 oil changes in 300k either, but for whatever reason, that's the way it happened. What's really weird, is how good it still runs. No leaks, no smoking, and no usage. It would shock me to add a quart in 10000 miles with this engine. Two radiators, two transmissions, a starter, a alternator, a ac compressor, and about 7 sets of tires, and its still going strong.

 

Zddp is still in oils, just at smaller amounts. It was found to damage catalytic converters, which have become more and more important.
The oil and valvetrains of today don't require zddp, but many still seek it out, hoping to extend the life of their engine further. The damage isn't quite as bad as some claim, but it does ruin cats and a damaged cat is going to cause the engine to run an out of whack fuel:air ratio, which will in some way cause damage, theoretically offsetting any "gain" seen by adding zddp.

You are also correct that is is classified as toxic to aquatic life and so there are concerns with pollution. Oil leaks out of tons of cars, hits the road, and the rain carries it off to the marine life.

two more points I might add: Ask yourself, is the life expectancy of engines going up or down? Now consider whether ZDDP matters. All of these people claim it was so good and used to be used in higher quantities, but now engines last 2-3x as long. So does it really matter?

Secondly, I am afraid I don't remember the specifics, and it would take some time to find the article, but I have read before about the levels of ZDP in oil today and long ago and its effects on engine wear. It turns out that there is a level of diminishing returns, where extra ZDDP does more harm than good, like putting too much anti-freeze in your cooling system. The level ZDP is currently at is much much closer to what it needs to be.


Adding it is basically a pointless waste of money.too much of the phosphorous (0.20%)will also attack metal and cause spalling

 

I previously used Mobil 1 HM 10W40 but this Summer decided to try Mobil 1 0W40. It seems to work fantastic in my XJS V12 and runs smoother/quieter then the 10W40 oil. My oil pressure stayed the same as the 10W40 and also the 20W50 that was used when I first purchased the car. I also noticed a slight drop in temps with the 0W40 oil... I also would not use MMO or any other additives if you are already using a high quality syn oil. Mobil 1 0W40 is already loaded with moly/ZDDP and I would not mess with its formula.

 

Oh, believe me. I have no desire to deal with ZDDP. I'l take my synthetic and be happy.

 

An oil being synthetic is no guarantee that it has enough ZDDP.

If a given engine design requires greater than 900 ppm ZDDP, very few synthetics offers this.

 

Yeah, and I'm fine with that. I wasn't aware of any ZDDP requirements in any engine I've ever run.

 

Mobil 1 HM and Mobil 1 0W40 all have more then enough additives for long engine life... Rotella oils all have enough zinc, etc... The only cars I ever added more ZDDP were modern motor oils used in my Muscle/Classic cars that were pre-1970...

 

The need for sufficient ZDDP goes way beyond '70s era muscle cars. Essentially, any flat tappet engine requires them. I use Rotella (or whatever CJ4 oil is on sale) straight out of the jug rather than doctoring modern oils with an additive.

 

I agree with you and in most cases you would not have to add any zddp...

 

ZDDP was added in the 50s to help with wear from more aggressive cams like we use today. It was increased again in the 60s and 70s because it was the most readily available anti-oxidant to fix thickening issues.

It didn't go down again until it was discovered it was harming cats.

The idea that, because the engines were designed during that time period, they require that exact amount of zdp is a little out there. It would suggest the engineers built the engine from the ground up based first and foremost on the zddp levels in the current oil rather than any other engineering aspects of an engine, which is too much for me to believe.

The current zdp levels are pretty much what they were when it was first introduced for its anti-wear properties. It has been reduced to those levels because the higher levels damage cats and other additives have been found to replace it as an anti-oxidant.

The claim that it is bad levels are lower, because the engine was made when they were higher, ignores why they were higher or the history and use of zdp previous to those peak levels.
If it were as big of a deal as some people claim, why aren't there millions of cars on the side of the road that don't have roller cams because they are using modern oil?

 

If you hang around the old Corvette or muscle car boards like I do, there plenty of direct evidence that using modern, low ZDDP oils is risky.

Here's an interesting article written by and acquaintance of mine in CA that will take the myth and mystery out of the equation. It starts on page 3

http://stlouisncrs.org/news_files/St..._July_2011.pdf

 

Again that is twisting information. The levels increasued to 1200-1400ppm when more zddp was added in the 60s and 70s as an antioxidant. When it was introduced in the 50s to prevent wear, it was used at similar levels as today.

ZDDP was never increased to those levels to reduce wear.So all that about it being at a certain level when the engines were made is misusing the information. The only "evidence" I have ever seen of modern oils causing wear is pictures of worn cams after an engine break in....but I have a hard time believing if the person improperly broke in an engine and messed things up, that they would take fault for it. Easier to just blame it on zddp since the bandwagon is so large.

I have yet to see any real research or evidence. Just this same nonsense that levels were once a X and now they are at Y so X must be better for my engine because it was made in that same time period, regardless of why they were reduced or whether its levels were taken into account when making the engine.