4.3 L V6 Oil Change Warning

[Zathrus]

Don't be lazy with your oil changes!

Don't think that your boat doesn't need an oil change based on what see on your dipstick!

During my pre-season prep on my newly acquired 2005 Maxum 1800 SR3, I noticed something disturbing and wanted to pass it along to you guys. The prior owner must have thought this even though he told me he changed the oil every season. When I looked at the dipstick it looked really clean but when I drained it (the proper way) the colour shocked me. It was "dark black" (very dirty) and couldn't have been changed in years. It was so sad to see as the engine was recently rebuilt and only had 105 hours on it. I realized why.

The dipstick on this particular year engine (2005 4.3L) and possibly many more models, doesn't feed through the engine block and dip into the oil from above. Instead the tube runs down the side of the engine to a "T" fitting attached to the drain on the oil pan. That's fine for checking the oil level, but because of this, oil in the oil pan never really mixes with the oil in the tube and doesn't change color or represent the actual condition of the oil. It also won't show signs of water in the oil. How ridiculous is that? Especially on a boat engine!

[The Pirate]

Not unlike the situation I had with my 4.3. Bought on-line, sight unseen. Could best be described as, "little use, even less maintenance". Oil was 1.5 qrts low and very dirty.
I've used Marvel Mystery oil since prior to oil change and fresh filter.
Probably 4 changes since. Has gotten better and better in terms of it flowing out, even if a bit cool.
Excellent point about the dipstick not reaching all the way into the pan and not reflecting whats actually in the engine!

[shrew]

Yes, the dipstick tube creates a vacuum, like holding your thumb over a drink straw. As a result, the oil doesn't circulate through the dipstick tube.

This is why you shouldn't use the dipstick to determine if there is water in your oil. It is better to drain, or pull a valve cover.

[DirtyHippo]

interesting photo with the drain hose coming through the transom drain. do you have a photo of the other side attached to the engine? i will be looking into chainging the oil next year in my boat (just got it and used it once then winterized it) and i'm going to be looking to set up the best way to drain without too much hassle

[Zathrus]

Hi DirtyHippo and congratulations on your boat purchase!

I photoshopped my 1st picture to better illustrate that oil pan fitting. I did a search online for the "dual" fitting but all I could find was a drain hose kit.

I hope this helps, Happy boating!

[Zathrus]

Note: The oil drain hose "swivels" so you can point it up and suck the oil out with a pump or down and out the transom drain hole into a pan. Either way it makes for a mess free oil change.