SAE 30 for a 1997 5.7 EFI?
- Thread starter alwhite00
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JVM225
Well-Known Member
I think that Mercruiser recommends their 25W-40, but I know that some use straight 30W instead. I've also seen others use the Rotella diesel oil. I think the weight is 15w-40 on that. I've been using the synthetic blend of the Mercruiser (Quicksilver) 25W-40 in my motors. It's more expensive, but it's only two motors and the oil gets changed once a year so I don't mind the extra cost.
I think that the marine oils have additives in them that help with that specific environment, but truth be told I've never heard of a marine motor going bad because of the weight or brand of oil that was used in it.
I use Fram PH30 fliters on mine and buy them at Walmart. The AC Delco # is PF 25. The 97 motors should take the same. I'm sure you can check the cross reference catalogs for whatever brand you go with. If in doubt, just look up the number for any pre-LS Chevy V8's.
I think that the marine oils have additives in them that help with that specific environment, but truth be told I've never heard of a marine motor going bad because of the weight or brand of oil that was used in it.
I use Fram PH30 fliters on mine and buy them at Walmart. The AC Delco # is PF 25. The 97 motors should take the same. I'm sure you can check the cross reference catalogs for whatever brand you go with. If in doubt, just look up the number for any pre-LS Chevy V8's.
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magstang1
Active Member
I'm just wondering why you would spend the extra money on quicksilver oil yet use automotive grade fram filters?
Maybe I'm mistaken but I thought automotive filters had more filter material to trap more particles which made them more restrictive.
Generally speaking you run a marine engine at twice the RPM of an automotive engine, which requires more oil flow.
Again, maybe I'm totally incorrect.
Maybe I'm mistaken but I thought automotive filters had more filter material to trap more particles which made them more restrictive.
Generally speaking you run a marine engine at twice the RPM of an automotive engine, which requires more oil flow.
Again, maybe I'm totally incorrect.
JVM225
Well-Known Member
I'm pretty sure that Quicksilver (Mercruiser) actully sells a high performance filter that traps even more than any standard automotive filter. For some reason an advertised 97% rings a bell. Other than that I think the only thing I remember them advertising about it is that it has a dfferent paint process to stand up to the harsh marine environment. Although, I can honestly say that I've never had a filter rust through on one of my motors. I think it costs like $10 or $14 or something.
Other than that, I really don't know that there is that much of a difference (if any) between an automotive filter and marine oil filter. If I find out that there is and it really makes a difference then I'll switch.
I understand that the additives in oil designed for marine use are a bit different than what is in automotive formulas.
The environment in a boat is different and the marine engines generally operate at higher RPM than car engines for longer periods of time. There is also usually a lot more "dry" starts in boat motors. Most people start their cars a lot more frequently than they start their boats and have less time where the car is sitting. Hopefully the marine specific formulas of oil provide longer lasting coatings on internal surfaces than the automotive formulas to help reduce the impact of these "dry" starts.
Once again though; I don't ever remember seeing or hearing of a boat motor going bad because of the weight or brand of oil that the owner used. I just use what I use because it is what the people who built the motor recommend. I realize that what they recommend is what they sell, but it doesn't cost me that much more to just go with the flow.
IMHO: Regular oil changes and frequently checking oil levels is much more important.