0W40?
 

Starting in 2019, GM changed to a 0W40 engine oil for all Corvette engines except the LT6 which uses a 5W50.

Has anyone tried a 0W40 in the first generation LT5?

I would think that the same two major advantages?1) oil gets to bearings more quickly on cold starts and 2) better thermal stability during aggressive engine operation?that GM gained with using a 0W40 in the 2G LT5 and the LT2 woulid be useful in the original LT5.

Re: 0W40?
 

I put it in my '90 (Mobil 1 0W40 European formula) because of the higher zinc and phosphorous and it seems to work well, quick starts, no noises, temps and pressures normal, no problems, can't see any difference in performance from the original Mobil1 that was in there before. Only time will tell.

Re: 0W40?
 

No experience with the Euro 0W-40, but I just changed my oil to Mobil Formula M 5W-40. No issues and quiet start up. Karl can tell us more about Formula M, but I like it so far.


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Re: 0W40?
 

I am using Mobil 1 Formula M 5w40 with no issues.

The European motor oils appear to have more zinc and phosphorus.

Car runs great and this is used in my 401 cid LT5. I chose this weight combo for all the reasons mentioned above.


https://i.postimg.cc/Fdt8Bb0x/Screen...909-060521.jpg

0W40?
 

Karl,

Thanks again for the recommendation. I have not drank the AMSOIL Kool-Aid and they will not reasonably ship to military address overseas; Mobil 1 Formula M is easy to get. BTW, your image you posted is blurry AF.


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Re: 0W40?
 

Edit

Re: 0W40?
 

Thanks for the replies, folks.

For those who use M1, the latest 0W40 is "Mobil One Supercar". Among others, it's the factory fill on C8s w. LT2s. M1 "Supercar" is the 10W40 ESP that was rebranded.

Re: 0W40?
 

Every time this question comes up, some are quick to say they have tried it in their motors w/o any issues. But, lubrication issues seldom pop up until considerable run time has occurred under typical wear scenarios or under stressful scenarios.

I dunno 'bout Uz, but I can't afford to experiment with my engine - too rich for my not-so-deep pockets. Therefore, I would prefer to see some comprehensive, scientific testing and comparisons between historic results with a former recommendation lubricants and the new product (good as it may be!).

Our LT5s are flat tappet motors and rev limits are ~ 7100 rpm to 7500 rpm (in some modifications). And, the ZDDP of the oils recommended at the time they were being built (by Mercury Marine), the zinc/phosphorous levels were in the ~1200/1300 ppm - to accommodate the demands of those (LT5) engines.

However, air pollution mandates resulted in reducing (in part) the ZDDP levels. And, offsetting the reduction of reducing the ZDDP, flat tappets gave way to roller tappets and rocker arms, etc.; both roller tappets and rockers are still in use today. My point is: aren't we comparing apples to oranges here? That isn't to say that this or that GM oil recommendation will spell trouble for our first gen LT5s. But, it remains to be seen if the new oil recommendation can bridge the gap between the specific application (roller tappets/lower rpm vs. flat tappets/high rpm) requirements.

Your mileage may vary. But, as for me - I'll stay with the "Kool-aid" until something else proves to be better...hopefully in an application other than MY LT5! Just sayin':)

Re: 0W40?
 

Excellent Summary Paul :thumbsup::cheers::cheers:

Re: 0W40?
 

Well said!