C40GT in non GT cars

[949oil]

Hi all

Long time lurker but joined officially. I've learned a lot from people here but have a question I can't find answer to.
Maybe it's buried in somewhere but I can't find it so apologies if my question has been answered before.

I have left over C40GT engine oils from my 992 GT3 days. I've sold the car to a dealer so I am wondering if I can use it in my other Porsches.
I understand C40 oil can be used in A40 engines. I have 3 Porsches that take A40 - 997 GT3, 981 Spyder, and 987 Spyder.
As I understand C40 and C40GT oils are very similar except the GT oil is designed to protect DLC coatings on cams, it just sounds like an improved C40 oil.
Would there be any harm in using the GT oil in engines that call for A40?

TIA

 

[JavierH19]

Yes. Just drain the bottles down to 1/3-1/4 and shake them good to reintegrate the additive pack that would have likely fallen out of suspension but it wouldn't be much and the anecdotal i've heard on here is that mobil oil is pretty good on not separating like others so it might not even be necessary.

 

[949oil]

I did hear about shaking the oil bottle but figured everything was going to be all coming out either way. I used to not soak oil filters until 5 years ago, so I guess shaking the bottle could be a new habit I start doing during an oil change.
Thanks for the answer. It's good to know I do not need to waste the GT oil stack I have on hand.

 

[Indyxc]

Adding to this. New car has C40 GT, and I will have to run C40 GT for the next few years for warranty sake.

To keep things easy and clean, any reason I can't run this in my S55 BMW, use case yearly oil changes, less than 3000 miles?

 

[scrllock]

As I understand C40 and C40GT oils are very similar except the GT oil is designed to protect DLC coatings on cams, it just sounds like an improved C40 oil.
Would there be any harm in using the GT oil in engines that call for A40?

Unless someone posts VOA we can only speculate but GT probably lacks MoDTC (for DLC compatibility). They presumably have another, more expensive friction modifier in the GT product. Seems like a waste of money to use it on another engine but would be fun to see results.

 

[chris719]

Adding to this. New car has C40 GT, and I will have to run C40 GT for the next few years for warranty sake.

To keep things easy and clean, any reason I can't run this in my S55 BMW, use case yearly oil changes, less than 3000 miles?

It should be fine, but there are probably few people on the planet that know what additives are compatible with what coatings now AND what engines have parts with exactly which coating.

It could be that no one knew ESP X3/X4 wasn’t fully compatible with the DLC until they had issues, which is exactly the kind of thing only testing reveals. When I asked Haris Junuzovic from XOM about using ESP X3 in an S55 he said to use the FS simply because they had never put ESP X3 in any BMW engine for testing.

I probably would be comfortable using it in a BMW engine though.

 

[Indyxc]

It should be fine, but there are probably few people on the planet that know what additives are compatible with what coatings now AND what engines have parts with exactly which coating.

It could be that no one knew ESP X3/X4 wasn’t fully compatible with the DLC until they had issues, which is exactly the kind of thing only testing reveals. When I asked Haris Junuzovic from XOM about using ESP X3 in an S55 he said to use the FS simply because they had never put ESP X3 in any BMW engine for testing.

I probably would be comfortable using it in a BMW engine though.

That's kind of my thought. S55 is pretty robust, only unique thing is the spray coated cylinder bore liners, and I don't think the cams are DLC coated in the S55. C40 should be just fine for it.

 

[chris719]

Main issue is that Pennzoil Platinum Euro 5W-40 exists, I think that's a really good oil I doubt anyone knows if ESP X4 is really any better.

 

[Indyxc]

Main issue is that Pennzoil Platinum Euro 5W-40 exists, I think that's a really good oil I doubt anyone knows if ESP X4 is really any better.

I agree, but my GT3 is under warranty, and I have to run the C40 GT. I like keeping 1 oil in inventory.

Ironic thing is my wife had a GMC Terrain Diesel and it ran Pennzoil Platinum Euro 5w40. I remember at the time it was a big hard to find, but once Walmart got it, it was easy.