Last weekend I drained the oil from the bottom outlet on the bottom of the oil pan on my Universal M18. The engine had been warmed up to 160 degrees. I drained the oil with a vacuum style oil drain pump until I could hear the sound of air coming the engine. I pumped some more to be sure I had it all out. I checked the see-thru side of the reservoir of the pump. It was filled to the 3 quart mark. I removed and replaced the filter. The engine manual calls for 3 quarts of oil with filter change. I put in exactly 3 quarts. I started the engine and ran it to check for leaks, etc. I shut off the engine and checked the dipstick. The dipstick shows the engine has too much oil in it, perhaps by about 1 quart, but who knows?. Is the dip stick incorrect? Someone on another forum suggested this could be due to the fact that the M18 is mounted on a slant in a Cape Dory 30B.
Universal M18 Oil & Filter Capacity
- Thread starter Chesapeake Bob
- Start date
My M-18 manual says between 2.5-3 quarts. I use a Fram filter because they are smaller and allows more room for the coolant line that runs above it. I find that 2.5 does it. It takes several hours for all the oil to drain back to the pan. After the engine cools, it always shows a little bit higher. Drain out 1/2 quart and you should be golden.
What this teaches you is what we all learned the hard way, i.e., what you just did. 
In the future, when you change the oil, add only about 70% of what you think you need, and give it time to drain down into the sump/pan. Check it a few times and just add little bits until you reach the fill marks, there are usually two: low and high.
In the future, when you change the oil, add only about 70% of what you think you need, and give it time to drain down into the sump/pan. Check it a few times and just add little bits until you reach the fill marks, there are usually two: low and high.
Stu, so are you saying the engine manual is incorrect when it states "3 quarts" (with filter)? Should I only be refilling with 2 1/2" quarts in the future? The refill was exactly three quarts. The fact that the engine is mounted on an angle is an interesting thought. In theory, it would be impossible to get an accurate reading unless the dipstick was corrected to allow for the angled mounting. Thanks.
Curious. If you actually took out 3 quarts, and the dipstick registered full before you took out those 3 quarts, it should take 3 quarts to refill to full on the dipstick. Are you sure you removed 3 quarts?
Other than that, my M-18 takes about 2.5 quarts but after 14 years of changing the oil I still approach it like Stu.
I know that Maine Sail has a lot of experience with the Universals. I was hoping to see him weigh-in on this one. Thanks everyone!
Assume the manual printed by the OEM is most likely correct. The dipstick may not be correct if the engine as installed is angled or the boat trim is affecting the stick oil level. I'd run 3 quarts if that's what the manual says. The guys who built the engine know best.
Less oil results in higher oil temps, which can break down the oil's effectiveness (if taken to an extreme).
Less oil results in higher oil temps, which can break down the oil's effectiveness (if taken to an extreme).
Most sailboat inboards are slanted aft. On the M18, this makes the dipstick more sensitive to level. If I'm 1/2 a quart low, no oil shows on the dipstick. And just 1/4 quart high, way over full mark.
The m18 takes 2.5 qt. my best guess is that you didn't really remove 3 quarts from just the pan. The pump reservoir must be inaccurate or splashed oil may give false reading or etc. whereas the new-oil bottles will be exactly accurate.
The m18 takes 2.5 qt. my best guess is that you didn't really remove 3 quarts from just the pan. The pump reservoir must be inaccurate or splashed oil may give false reading or etc. whereas the new-oil bottles will be exactly accurate.
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Often times the vacuum tube is not at the absolute bottom of the oil pan and some oil will still be inside the engine. This is often the result of the engine bed & shaft angle. Sometimes sucking the oil out when it is cold will get more old oil out, but it takes about 6-8X as long because the oil is so thick when cold.
Regardless fill it back to the full mark on the dip stick and then be sure to check it again when the engine is cold. On some engines so much oil remains in the pan, no matter what you do, that a double oil change is the only solution to have it clean enough for a winters rest.
No, what I'm saying is that the manual is right but you can NOT get it ALL out. Others have commented on why since your question was posted. You either do what Maine Sail says, or just replace most of it and keep on going. Been working that way for me for 18 years. My boat, my choice.
Thanks for the thoughts everyone. (Stu, I was not questioning your wisdom or experience.) The oil looks nice and clean on the dipstick, but it would appear that I need to drain just a "scoshe" out to lower the level. Thanks again!
Chessie Bob, what they're saying is that no matter what the manual states, put in less than the full amount and then check the level on the stick after waiting a bit. Adjust from there. The amount in the manual is probably correct but maybe all the oil hadn't all drained down before you sucked it out, or maybe, as IStream said, it had already been high. Whatever the case, it's best to sneak up on it from the low side.
Chesabob. You do not say whether you replaced your oil filter. If you did not then this would account for the excess oil. The 3 quarts (quaint language, USA must be the only country in the world still using quarts) with oil filter would no doubt mean that the engine and the oil filter combined would take 3 quarts. If the oil filter was not changed, then the oil in the oil filter would account for the difference. (I think, but I have no idea how much a quart is??)
BTW. When we change oil on our Ford 75hp, we remove the oil filter, put a bucket under where it is fitted, and run the engine for about 30 seconds. It belches out all the oil (about 10 litres, no idea what that is in quarts) in no time. My engineer encouraged me to do this as it has no effect on the engine ("groan" I can here some old timers saying) (And bear in mind I am nearly 70) But have done this so many times now, and no issues, so must work. And it is quick.
BTW. When we change oil on our Ford 75hp, we remove the oil filter, put a bucket under where it is fitted, and run the engine for about 30 seconds. It belches out all the oil (about 10 litres, no idea what that is in quarts) in no time. My engineer encouraged me to do this as it has no effect on the engine ("groan" I can here some old timers saying) (And bear in mind I am nearly 70) But have done this so many times now, and no issues, so must work. And it is quick.
The problem is that the dipstick on every Universal engine that I have ever worked on will not allow you to drain from the bottom of the pan. Further, if the engine is canted aft, as it is on Catalina, O'day, and Cape Dory, the engine drain plug, which IS at the bottom of the pan, is at the front of the engine. I have found that the pan usually retains about a quart of old oil unless you drop the oil pan (eighteen 10mm bolts if I recall correctly).