2008 246 BR using oil

[summer friend]

I have a 2008 246 with the 350 mag and it uses 1 to 2 quarts of oil every 25 to 30 hours is this normal?

[alswagg]

No it is not.  What grade of oil are you using?  25W40 as specified by Mercruiser?  1qt per 100 hrs is normal.  Al

[summer friend]

I'm using the 25w40 syn. I do run at higher rpms (40 - 4500) for most all my boating.

[alswagg]

The 350 mag has an oil capacity of 5 1/2 qts including the oil filter and cooler.  How much are you installing during a routine oil change?  I have heard of some having the wrong dipstick and actually allowing too much oil to be in the pan.  This will cause oil usage also due to the cranck journals are splashing in the oil.  Check the part number on the dipstick and verify it is correct with model engine you have.  Good luck  Al

[summer friend]

Everthing is correct as far as the oil capacity and dip stick go, but luckily I found out today after calling the dealer I'm still under warranty until the end of the month. So they started a warranty claim on it and we're going to see what Rinker says about it.

[AlexisandChad]

Good Luck!  Keep us informed. We are always trying to expand out knowledge base.  Except for Al, he need's a brain dump!!   

[alswagg]

Sorry, but Rinker won't do anything for the engine.  The Engine is warrentied under Mercruiser.  Hopefully your dealer sent in all the correct paperwork.  Good luck  Al

[summer friend]

The dealer heard back from Mercruiser today and they said at full throttle it is acceptable to use 1-2 qts every 12-16 hours and 1-2 qts every 16-20 hrs at average throttle.

[Gene]

I dont buy it. If I told a truck owner it was normal to have to a quart between every oil change he'd shoot me. Seems excessive but I dont pay the warramty claims, My 454 Merc with 300 hours doesnt use a drop all season. Tyr adding a can of BG MOA found at Big A or Napa or Car Quest.

[summer friend]

It's still hard for me to Believe but since it's not leaking or burning oil where do you start to diagnose this problem?

[earl1z19]

There is a good chance it is burning it. With the exhaust exiting in the water it would be hard to tell unless you had an extreme problem.

[Gene]

Obviously if you don't have oil in the bilge it's not leaking. I would say it's burning it and the only way to tell would be to start checking basics like looking at the spark plugs first. If one looks browner or oily that's the cylinder to start with, get a compression test done to start with. All the cylinders should be within 5-10% of each other if the engine is in good shape. I do not know what the compression should be as far as PSI. You may also have a valve seal or valve train issue but that's doubtful I think.

[alswagg]

Try replacing the PCV valve.  If the valve is stuck open,  the engine will suck more than required out of the vent system.  The oil will also get sucked out somewhat.  Good luck  Al

[Gene]

Try replacing the PCV valve.  If the valve is stuck open,  the engine will suck more than required out of the vent system.  The oil will also get sucked out somewhat.  Good luck  Al

yes Al I forgot about that also.

[Oldntired]

A little information on rings as they are engineered.  Some engines have controlled oil burning as a function of lubing the pistons.  This is usually on high performance engines such as the HP Chrysler engines of the '60s and early '70s which were designed to burn about one quart in 600 miles.  All engines have some degree of burning designed into them.  I have no information on Mercruiser engines as to oil burning but the information that you received may very well be true.  All mechanical parts have tolerances and you may just have several ring sets that hit the low end of tolerance.  I had a six pack 440 that was a pain to keep plugs in if my wife drove it because of this.  Again I have no knowledge of Mercruiser engineering so this may or may not apply.