Quicksilver 25w40 or Pennzoil 40w Marine ??

[PT1]

My brother has a SeaRay boat with a 7.4L GM engine and his dealer says to use the quicksilver 25w40 which is almost $5/qt. He says he can get Pennzoil Marine 40w at Wallyworld for $2.40/qt but wants to run the 40w because it is never below 50 degrees when he starts the boat. I told him I would ask the experts. Well what do you think??

 

[alreadygone]

I'd say that would be an excellent choice. If you look at oil chart in Merc manual, straight 40 is next prefered choice. I've been using Delo, or Rotella 40 in inboards for years, excellent results.

Bob

 

[PT1]

Does it handle fuel dilution better than the 25w40?

 

[Geoff]

Indmar recommends Pennzoil marine 15w-40 for all engines except the big block 8.1, which gets a straight 40w rec. I have seen same straight 40w for the 7.4l engine.