Using car oil

[1ranger487vs]

Will using car oil of the same weight like castrol or pennzoil void my warranty

[Facemelter]

The main question I like to ask when this question comes up.

How often are you changing the oil in your boat motor?

Second question.

Why give Mercury any kind of out to be on the hook for warranty coverage?

[bass-action]

Pretty sure there are extra additives in marine oil for moisture/water.

[mactlman]

Pretty sure there are extra additives in marine oil for moisture/water.

this!!!

[Johnnyred]

Pretty sure there are extra additives in marine oil for moisture/water.

Water buildup in 4 stroke outboard oil requires marine oils and their special additives to minimize its ability to cause damage. They are of course cooled by a constant supply of cool lake water therefore do not reach anywhere near the oil temps of an automobile. The water vapor that is a normal part of the combustion process builds slowly in the outboard's oil that would otherwise escape through an autos tailpipe. The base oils may be the same in a 10w-30 auto and marine oil but the additives definitely are not.

[EuropeanAM]

Pretty sure there are extra additives in marine oil for moisture/water.

Car oil does not meet the specifications for your marine engine.

Additionally, most automotive oils have the friction modifiers removed (the ones that help to protect your high-RPM outboard), and lack many of the additives that help to combat corrosion, condensation, etc.

And finally: Most of the 4-stroke oils are BLENDS (rather than multi-viscosity).

Biggest key to not meeting specs is NMMA-FCW Certification.

[Michael333]

I wouldn’t do it. Marine engines operate at much cooler temperatures. Auto oil is not intended for that.

[1ranger487vs]

Will that cause it to void the warranty

[mactlman]

Will that cause it to void the warranty

It’s your engine do it you think is best. Let us know how it works out in the end

[SilverFox579]

Will that cause it to void the warranty

If Mercury determines the oil used caused the failure and did not meet specified requirements, you bet.

The chart GPtimes posted shows the specified oil -- FC-W or FC-W Cat 10w-30. Automotive oil is not NMMA FC-W certified.

The bold text above the specification chart is clear:

IMPORTANT: Nondetergent oils, multiviscosity oils (other than Mercury or Quicksilver NMMA FC-W certified oil or a major brand NMMA FC-W certified oil), full synthetic oils, low quality oils, and oils that contain solid additives are not recommended)

Run whatever you want in your engine run and pray you never have an oil related failure.

[goodman_fishing]

Don't do that. Cars dont sit at 6,000 rpm for 10-20-30+ minute runs.

[1ranger487vs]

Every 50 hours

[ifishinxs]

There has been some testing in this regard. The info is out there if you want to take the time.
Bottom line is that these motors are exspensive. There are a bunch of marine oils on the market that are acceptable.
After sifting through all the information. I decided that Mercury/Quick silver synthetic blend is as good as it gets and is priced where it should be.

[1ranger487vs]

The question was will it void your warranty

[Johnnyred]

The question was will it void your warranty

Short answer: No a manufacturer cannot just void a warranty for something like the oil you choose. That is against federal law. Manufacturers have to prove that an action you take (like your chose of oil that you put in your outboard) caused the damage that you are making a warranty claim for (like lubrication-related engine failure). They can always deny a warranty claim which is completely different than voiding your warranty. Voiding a warranty means you have no warranty coverage for anything.

But really this is the wrong question to be asking and the wrong way to look at it. The question is what can I/you do as the owner that will maximize my/your chances that my outboard will last and avoid repairs? With respect to engine oils for an outboard, the answer is use an oil that is formulated for Marine engines and is FC-W certified. Look at your outboard's manual to see if they recommend a full synthetic or a blend.

[Zone18]

The question was will it void your warranty

Im sure if they could prove the oil was not manufacture recommended type they would most certainly deny your clam if you had one. You need to follow the rules the engineers set just to be on the safe side. Why would you not want to? saving a few dollars on oil could cost you 30k in the long run.

[moymurfs]

The question was will it void your warranty

(Correct me if I'm wrong.) Since the whole warranty covers more than oil related parts; I'm going to assume you really mean something like "Will Merc deny an oil related repair if I use car oil"
I still don't think there is a definitive Yes or No answer.
If the person who was doing it, on an engine that was still under warranty, ACTUALLY told the dealer they were doing it, it might raise a question with Mercury. The issue would be compounded if the failure could be remotely connected to lubrication. Make no mistake, Merc isn't in the business to pay. The majority of Merc's response depends upon what their dealer tells them. Bottom line, If the owner told the dealer they were doing something other than Mercury required/approved, ESPECIALLY within the warranty period, then they (owner) deserve to pay for the whole repair.

[jrh_67]

I'm pretty sure using an improperly rated oil will void the warranty if you were to ever have an internal engine problem. The question I would have to ask is WHY would you use an oil that's not rated for marine use in your engine when it isn't recommended?

[PatriotAW4]

Regular gasoline engine oil no don't use it, diesel motor oil possibly depending on the weight, some of it is rated for marine use.

[Michael333]

The bottom line is run a marine rated oil with the correct viscosity, these motors cost too much money to try to use the wrong oil to save a few bucks. Use oil that is certified by the nmma.