Dipstick question

kneedeep

My 09 340 has twin 350's. when I check the port oil with the engines cold & then later in the day (waiting 20 minutes or so for all of the oil to drain) the oil is at the same level on the dipstick. On the starboard engine, there is sometimes a significant difference (an inch or more on the dipstick) & I'm not sure which level to trust?? Any ideas why there would be a difference? If I trust the lower amount showing on the dipstick, I'm low on oil, if I trust the higher dipstick reading, I have too much oil. I check the oil multiple times per weekend & have decided to trust the lower reading, which happens more often, but it freaks me out when I get the occasional high reading.

Black_Diamond

Did you change the oil or have it done?  Too much oil is bad, it will foam and reduce its ability to lubricate.  An inch is a lot of oil though to vary on the stick though.  Even if the oil is draining back from the filter (bad filter by-pass valve) it should only vary about .5 quart with is not an inch.

OldDogNewTrix

I've never noticed that but then again I usually only check the oil once a week. Now you've got me wondering, I.'ll pay more attention to it.

kneedeep

I changed it myself. I put 4 quarts in each engine. I'm not positive how much I sucked out because it all went into a 5 gallon pail that already had some oil in it. I did warm the engines up & took my time to get as much out as possible. The thing is, sometimes the dipstick shows one level and then a few hours later it can show a drastically different level! The other motor always reads the same.

Michael T

Gentlemen, I only check my oil and change my oil after the engines have reached operating temperature and had a chance to drain. Your oil level does not depend on how much you put in but rather on the following: How much did you take out? Did you change the filters? Did you swap dip sticks? did you change a dip stick? Are your oil filters the same size as before? Slope of the boat can have an effect oil level engine to engine from side to side and port to aft - but not that much (one inch). Anyweay you should treat each engine as an individual unit. What you put in one versus the other, in my opinion, is irrelevant. Right now, in your case, I would warm the engines up to operating temperature, allow them to sit for 10 minutes or so. Then I'd check the oil level on each stick and add to slightly below the top fill, then recheck. I have always gone with my "hot" oil readings on the stick(s) and that has served my engines well. MT

MarkB

Are you saying the level changes by more than an inch on the same dipstick. If so, it could be that the oil is wicking up the dipstick. So clean and measure a few times. It could take 5 or so measurements to get a good reading as the oil oculd be in the dipstick well itself.

OR

Are you saying the oil level difference between the starboard and portside engine is 1" different. If so, why would these two levels be related, unless you have some listing on your boat.  One could be low and the other ok.

kneedeep

I get different levels on the same engine, same dipstick, same weekend. I check the engine both cold & warm. When I check it warm, i Wait 20 minutes so that the oil all drains down. It's very strange.

aero3113

I wonder I the drain holes in your lifter galleys are clogged causing the oil not to drain sometimes?

212rowboat

Frothed oil will do this, but is usually accompanied by a loss of pressure.. do you see that at all?

kneedeep

Aero, the oil is changed regularly & I only have about 150 hours, so I'd hope nothing is clogged in the engine. Drew, The pressure for that engine (with fluctuating dipstick readings) is 50 at 3800rpm & the other engine (steady dipstick readings) is 60. BUT, I don't trust my friggin faria gauges! I'm getting vessel view over the winter. Back to the oil, frothed means bubbles, would I be able to see bubbles on the dipstick, or would they be gone by the time the oil settles back down into the pan?

212rowboat

I bet you're over filled a bit... It's easy to do.. you'll see froth on the bitter end of the dipstick, but not always.. it froths when the oil slaps against the crank under the windsor tray, and if it slaps enough pressure isn't possible.. very bad..

It's straight oil, though, right? Not a milkshake? Or chocolate fondue looking stuff? :-)

Oh... Pull your pcv valve.. shake it.. it should rattle.. if not, you may be building crank case pressure, which does the same thing to oil sometimes..

kneedeep

Straight oil, looks perfect on the dipstick. I'll check the pvc valve. Thanks.