No oil on dip stick after adding 6 liters

4.5 l mercruiser. Oil level on dipstick was normal before I started the change. First I tried putting a plastic tube down the dipstick tube..met some resistance (a bend in the tube), pushed by it and started pumping oil out. Only got a cup or so and sucked air. Plastic tube I inserted wasn’t long enough. Removed it and attached the proper end to the threaded part of the tube. Removed close to 5.5 l, when it came out, it was not a solid stream…. Had mix of air and oil bubbles, like you get when you are just about done.. but it did it for the entire extraction.
Put in 4.5 l new oil…nothing on dip stick..added more.. now up to 6l and just the tip of the stick shows oil (still below add mark). Dip stick is 37 inches including the yellow handle
Engine runs fine. Likely too much oil.. but scary with the dipstick so low.
Ant thoughts?

let the motor sit a few minutes. then read the dipstick

Yes, leave it sit with the stick out A bit. They like to vacuum lock, either I get nothing on the stick or it looks over full. Even when checking after it sits from the last time you ran it I pull the stick and let it sit for awhile. This is true with any motor.

It has sat for a few days..still nothing but the tip of the stick shows oil. Is it possible for the dip stick tube to be pulled up so the dipstick can’t reach the oil? The tube seems tight at the top, but I can’t see where it goes into the oil pan.

Does the dipstick tube connect to the bottom of the oil pan and not go into the side of the block? If so these set ups are prone to oil level changes due to temperature changes and can be very inaccurate. I find that if you pull the stick out and wait like 5-10 min allow the oil level in the tube to equalize with the level in the oil pan, you will likely get a more accurate reading. On mine (same set up with dipstick tube connected to the pan) with a hot engine, it reads low, because warm air in the tube doesn't allow the oil to rise up properly. Keep the stick out and re-check, and then you get a reading that makes sense. With a cold engine the opposite happens, the air in the tube cools off and creates a vacuum and pulls oil up the stick and it reads way overfull. Solution is the same, leave the stick out and the level will equalize.
I changed the oil a few times in my brother's boat that had the same engine, didn't run into that problem but probably because I am so used to leaving the stick out to allow the level to equalize.

Doug1or2 said:

It has sat for a few days..still nothing but the tip of the stick shows oil. Is it possible for the dip stick tube to be pulled up so the dipstick can’t reach the oil? The tube seems tight at the top, but I can’t see where it goes into the oil pan.

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worth checking it is all the way down - also worth checking do you have the correct dipstick.

Are you in a hoist , the water or on a trailer? willing to bet that the angle of the boat is affecting your reading. Not sure if there is a drain hose on the pan or suck up only ? if you can drain it completely and top it with correct amount use the level the correct amount goes to or bottom of stick

I will try again tomorrow. Warm the engine, pump out the oil, add 4.5 litres, leave the dipstick out 5 min and recheck. It is sitting level in the water.
Thanks for the suggestion of the dip stick level needing time to meet the level in the oil pan.

Measure your dipstick. I bet if you pulled your dipstick tube you would leak oil. If not you have oil disappearing somewhere?

Yesterday, with no oil on the dipstick, I ran the engine (oil pressure gauge was reading normal). Then I proceeded to pump out 6 litres of oil. I put 4.5 litres back in. Let it sit level in the water with the fill cap off and dipstick out for 20 min, and still nothing in the stick when checked. Started engine, oil pressure ok. No oil in the bilge, and no oily smoke from the exhaust.
Does anyone know, is the oil pan bigger on the 4.5 l 250 hp vs the 200 hp model? I have the 250 hp. Should I add more oil and see how much it takes? Or just run with the 4.5 litres of oil? Thanks for your thoughts.

Doug1or2 said:

Yesterday, with no oil on the dipstick, I ran the engine (oil pressure gauge was reading normal). Then I proceeded to pump out 6 litres of oil. I put 4.5 litres back in. Let it sit level in the water with the fill cap off and dipstick out for 20 min, and still nothing in the stick when checked. Started engine, oil pressure ok. No oil in the bilge, and no oily smoke from the exhaust.
Does anyone know, is the oil pan bigger on the 4.5 l 250 hp vs the 200 hp model? I have the 250 hp. Should I add more oil and see how much it takes? Or just run with the 4.5 litres of oil? Thanks for your thoughts.

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I would not over fill it but also would take dipstick to dealer and see if they can compare length as something is wrong here.

You may be able to find a universal replacement dipstick that hits the oil level

Are you sure that all of the tube and parts you pushed into the dipstick tube came back out? Odd that everything read normally before you changed the oil. Is this the first time you've performed this service on this engine? In not, were there any issues the last time?

All of the plastic tube I pushed in came out. The dip stick goes in relatively easily. The only thing different this year, is the boat was in for service.. bellows, spark plugs, serpentine belt, gear oil. I had done the engine oil change last year, so advised them to forgo that service to save some $.

Did you try the leaversit with the stick out yet?