2002 Mercruiser 4.3 Outdrive Oil and Motor oil

[Phil Chieco]

Is it safe to use a good quality 15w40 motor oil and 80w90 Valvoline outdrive oil in my 2002 4.3 mercruiser.

 

[PatSea]

I would go with whatever lubes are specified in the owners manual

 

[mixman]

As stated above, just match up the specs. I've got Honda outboards and I never buy re-branded "Honda Oil/Lube". Mercruiser (and Honda, and Yamaha, etc.) don't make lubes. I find buying the stuff at Walmart (oil filters too) saves quite a bit of $$$$.

 

[Phil Chieco]

What if I cannot find 25w 40 in another brand? I was hoping to use 15w 40.

 

[mixman]

You'll need to see if that viscosity is acceptable with Mercruiser. If not stated in the manual you'll have to contact them.

 

[sugilbert]

15w40 is just fine. In my OD's, however, I only use Merc synthetic.

 

[j-d]

The MerC synthetic gear lube is the best out there, and available at Walmart.

Likewise, if your 2002 calls for the MerC 25W-40 SynBlend, Walmart has that also.

Along with Oil and Fuel Filters, all branded Quicksilver, which is MerC's non-dealer retail (like Walmart) brand.

As noted earlier, Gear Lube is tricky. I'd stick with the MerC product.

Oil...? I was using straight 40HD and it got a little hard to find, so I went to 20W-50 Castrol, which was Dino Oil. But ya know what? The MerC oil at Walmart isn't all that much more expensive than quality brand automotive oils.

 

[BillK]

I've always used the Merc oil and get it at WalMart, just not enough cost difference for my annual oil change. But if you want to use something different you can (it's just a GM 4.3) here is what Merc says:

To help obtain optimum engine performance and to provide maximum protection, westrongly recommend the use of Quicksilver 4-Cycle 25W-40 Marine Engine Oil. This oil isa special blend of 25-weight and 40-weight oils for marine engines. If not available, a goodgrade, straight weight, detergent automotive oil of correct viscosity, with an APIclassification of SH,CF/CF-2, may be used.In those areas where Quicksilver 4-Cycle 25W-40 Marine Engine Oil or a recommendedstraight weight oil are not available, a multiviscosity 20W-40 (SH, CF/CF-2) or, as a secondbut less preferable choice, 20W-50, with API service ratings of SH, CF/CF-2 may be used.IMPORTANT: The use of non-detergent oils, multi-viscosity oils (other than Quicksil-ver 25W-40 or a good quality 20W-40 or 20W-50), synthetic oils, low quality oils or oilsthat contain solid additives are specifically not recommended

As far as gear lube, I really would stick with the Merc High Performance gear lube.

 

[ALKA2710]

I use 15-50 Mobil 1. Best stuff out there is my opinion only.

 

[Phil Chieco]

Thank you for all the advice. I will stick with the Merc outdrive oil and find a good alternative engine oil most likely 15W 40. always used that in my 3.0 and never had issues.

 

[easttnboater]

I run Rotella T 15-40.

 

[j-d]

quote:

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Originally posted by ALKA2710

I use 15-50 Mobil 1. Best stuff out there is my opinion only.

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Mobil 1 sounds like a VERY good alternative. At its Walmart price vs Walmart for the Merc Quicksilver oil, looks close to two quarts free with each jug.

I like the Rotella idea too. Another oil that needs no introduction, anywhere!

I get lost in the Zinc/ZDDP discussions, but my understanding is that special care needs to go into oil selection IF the engine has a flat tappet valve train, vs the nearly universal roller type.

 

[JVM225]

I get the Merc 15w40 and gear lube at Walmart for my kids 3.0 Mercruiser. I could get something cheaper, but for the one change a year I go for the extra few bucks. I also add a bottle of STP that costs less than 3 bucks at Walmart. The STP has ZDDP in it and I feel like it leaves a nice film on everything which helps when long periods of time go between starts. For that reason I use the STP in my 68 GTO, C6 Corvette, and both of my kids cars. My wife and I drive leases that get used every day so I don’t bother putting it in them.

 

[GeeBee]

For the outdrive use the Merc synthetic. That is an area where you want the exact specification.

For the motor 15W-40 is fine. I also have used Rotella also for many years. Using a diesel rated oil is better than a gas engine rated oil because it has more corrosion inhibitors and more copper and zinc ideal for marine engines.