T5 Rotella Oil in a PCM ZR4?

[Puddleracer]

Hello everyone.

Just joined this group as I've upgrade to a Nautique.
I have a pail of semi synthetic T5 Rotella 15w40 oil from the last boat and wondering if I can use it up on my 2017 GS22 with the ZR4 6.0 L motor?
Seems to meet all the criteria in the manual but my local shop says I require fully synthetic.
Thanks in advance.

[NautiqueJeff]

Your dealer is correct. See the updated oil specs from PCM here:

PCM Oil Specs

[Jonny Quest]

I wonder how PCM (with GM's approval) can send out Service Advisory #SAP2019-01 with a straight face. This Service Advisory states that the PCM/GM engines require Dexos 1 Gen 3 oil -- 5W-30. It goes on further to say: "These engines are designed specifically for the use of Dexos 1 Gen 3 formula engine oil." (Yes, the Service Advisory uses Dexos Gen 2 language, but Jeff clears up that ambiguity by stating that Dexos 1 Gen 3 is the current backwards-compatible Dexos formula). Interesting to note that Gen 1 came out in 2010, Gen 2 came out in 2015, and Gen 3 came out in 2021.

So, one might ask how the PCM ZR6 (GM 6.0L LQ4 engine) that was introduced in 2003 was "designed specifically" for the use of a Dexos formula engine oil that came out 7 years later. Even more intriguing is the PCM Engine Manual for the 2003 ZR6 that states:

"Synthetic engine oils are not recommended for use in PCM Engines. Synthetics may offer advantages in cold-temperature pumpability and high-temperature oxidation resistance. However, synthetic oils have not proven to provide operational or economic benefits over conventional petroleum-based oils in PCM Engines."
Interesting how Dexos 1 Gen 3 must be fully synthetic to meet spec.

The PCM Engine Manual also states that the recommended engine oil for operations above 50 degrees F is 15W-40. This language was consistent through model year 2019 in the PCM Engine Manuals.

Even more interesting is how the GM 6.2L L87 engine that has been plagued by many lubrication-related problems has prompted GM to issue a "fix" by changing the oil spec from 0W-20 to 0W-40.

Well, I don't plan on switching to 5W-30 any time soon in my ZR6. Think I'll stay with Shell Rotella T6 15W-40...full synthetic. GASP!

JQ

[Nautiquehunter]

I use Mobil 1 15w50 in all my boats from 1963 to 2016 never had a problem. My 08 210 has 1500 hours . I change every 50 hours with trans fluid .