Engine Oil

[Boilers2000]

Wanted to confirm the proper engine oil for a 92 Mercruiser 4.3LX. I believe its 25-40W, service manual is being vague/can't find where I found it before. I question it because I'm ordering a new oil filler cap and the one I was going to order per the parts list shows 5W-30. Second guessing myself. Thanks in advance.

 

[HT32BSX115]

Howdy,

Here's the "official" answer

http://www.mercurymarine.staging.yar...ercruiser.aspx

This site is pretty slow to load for some reason.....

Here's what they say there:

What type of oil should I use? Can I use synthetic oil?

Engine Oil

To help obtain optimum engine performance and to provide maximum protection, we strongly recommend the use of the following oils listed in the order of recommendation:

1. MerCruiser / Quicksilver Synthetic Blend, NMMA FC-W rated, 4 cycle oil.

2. MerCruiser / Quicksilver 25W40 NMMA FC-W rated oil.

3. A NMMA FC-W rated oil.

4. MerCruiser / Quicksilver 4-cycle 25W40, non FC-W rated oil.

Note: The use of non-detergent oils, multi-viscosity oils (other than as specified), non-FC-W rated synthetic oils, low quality oils or oils that contain solid additives are specifically not recommended

Let me also add that usually, if you ask: "what type of oil should I use" on a discussion forum such as this one and MOST ALL other forums, you will get unlimited "Here's what I use and I've never had a problem" type answers......

Do a search here. There's a plethora of oil threads that say the same thing......If you don't want to use whatever Mercruy suggests, you can use pretty much whatever you want. It's all been tried with good results. Boat engines usually don't fail or wear out due to brand/type of oil used. They do fail for a "plethora" of other reasons.

YMMA

Cheers,

Rick

 

[Alumarine]

The cap you are ordering must be for a car or truck.

 

[Bondo]

Ayuh,..... I run Rotella T in 15W-40,....... You can run 'bout any oil you want too,......

 

[QBhoy]

Hi. Truth is that many oils will be just fine within the realms of your environment and of suitable weight to suit.
The official answer is quicksilver 25w-40. My advice is to use the quicksilver synthetic blend version. Not much dearer and 100% seems to keep its form better come the end of the season or when changing oil after the interval.
There are 100% better oils out there but I like to keep the service file OEM as much as I can.
Plenty of choices out there on marine orientated oil that will suit.
Ps. You’ll need 5 litres or more than the standard 4l tub it comes in usually. Perhaps 5 quarts is the us term ? The quicksilver only comes in 4 quarts usually or 1 quart. Unless you go commercial size

 

[Scott Danforth]

Oooh....another oil thread.........

 

[QBhoy]

Oooh....another oil thread.........

Haha. Thought the same. Without doubt the most hated and loved topic

 

[harringtondav]

If you can find a viscosity/temp chart for your engine you'll see Bondo's logic. I like synthetics. I go for one that meets the 40W min on the top end, 15 min on the bottom. I use Valvoline 20W50 VR. I never boat below 45 deg F, and like the viscosity for hot weather higher rev boating. Merc loves to sell their lubes, but there are others that work just fine.

 

[Boilers2000]

Even though the cap shows the box with a quicksilver PN must not be the true part.

Thanks for confirming the oil...hopefully someday I'll get to the same level of understanding of my engine and drive, until then by the book for me with confirmation from you guys.

Thanks again for the input and advice, this forum is invaluable for new boat owners!