I prefer conventional Castrol 20W 50 oil for summer time here on Cape Cod. My 91 XJS V12 Classic Collection Convertible has 70,000 miles. Thoughts on synthetic blend or full synthetic, will be appreciated.


91 XJS V12 Classic Collection with Dayton Wire Knock Off type Wheels.

 

I use Shell Rotella T.

 

20W 50?

 

I've read that non-synthetic (possibly what you mean by "conventional") is better for older engines (older designs) like the V12. Not sure if this is true, or why it would be true, but I do try to stick to it.

 

I use 20/50 until temps hit freezing then switch to 10/40.

I use whatever name brand conventional oil is on sale that day.

Some prefer synthetics.

Cheers
DD

 

I use 15W40 year round

 

10-40 Semi Synthetic all year round

 

Millers 10/60.

 

It must be spring! Along with the first cuckoo, the which oil is best thread has been heard! Nothing but fully synthetic 5W 40 for me! Any known brand: Shell/Mobil/Esso/Valvoline etc etc.
Sadly for all of us who have our favourites, what these threads seem to prove is that it does not matter as long as it is changed regularly!

 

Amsoil 10w40 marine diesel oil + LiquiMoly CeraTec friction modifier

 

That's nonsense.

 

I see no harm in synthetic oils, for the price point, I choose synthetic to take advantage of the extended drain schedule. Synthetic is marginally more expensive now. I use Castrol Edge 0w40, however I run the I6 engine.

 

All kinds of stuff on this. I'm with Doug. Clime here is mild. so, it is 20-50 dino oil of whatever is on sale. I do kinda like Valvoline also sold under the Carquest label.


My lump and Jeep do well on it.


Carl

 

The difference between regular and synthetic oil is the refining process. Synthetic is further refined to remove more impurities and additional additives are used. Synthetic oil is better at higher temps that modern engines especially turbocharged run.

IMO regular oil (viscosity based on climate where you live) and changed including filter regularly is all that is needed.

I use Aussie made brands only to buy local.

 

I've been buying extended interval stuff lately, just in case I get lazy and put off a change. Nice to know the oil will hold up

 

Isn't that a diesel oil? Shell has recently changed some of their formulations, some previously dual rated diesel/gasoline oils have dropped the gasoline ratings and are now rated for diesel service only.

Is that important? I don't know in this specific case. However, I do remember in a previous job I worked for a company that built large natural gas compressors for pipelines. They were driven by engines fuelled by natural gas, and there are specific oils just for natural gas engines. The customer was a major oil company and they had a policy to only use their own products.

However they didn't make an oil approved for natural gas use, only their competitors did. So they used their own gasoline rated oil and the engine didn't make it to the first oil change interval. The damage was so bad the brand new $1.2 million dollar engine was scrapped and they had to buy a new one - all for the sake of a few hundred dollars in oil.

 

Yes, Rotella T is a recommended diesel oil. The reason I started using it, was because of my fondness of the Triumph TR6, as well as a solid lifter small block Chevrolet. The TR6 engine has been known to have short cam lobe life due to wear aditives being removed from modern oils. Rotella T, as well as other "diesel" oils have extra wear additives. As I understand it, these wear additives "may" be bad for the o2 sensor(s) and or the catalytic converter. But as far as the oil, from what I understand, it is great for the wear of the engine.

 

I do about 2000 miles a year and change the oil every year, I just use whatever is suitable and cheapest from eurocarparts who have a depot just up the road from me

 

I think that pretty well pegs it, Greg.

Years and years ago...decades, actually.... I was very fussy about such things. I eventually realized that all that fussiness was making ME feel good....but the engine itself couldn't care less

Cheers
DD

 

Castrol is the oil for me
Proved superior many times over the years, but now I believe its owned by BP so things might have changed.
Was in the jag place earlier this week talking to there ( I think ) top mechanic, he has an XJS, says he runs 15-40 in his and there was a container of Castrol oil on the bench.
Our temperatures range from about 5 to 45deg