Oil capacity

[timharper89]

Mercruiser 4.3L 1987 s/n B459735. When I changed my oil earlier due to a flooded carb pouring gas in the cylinders, I checked the manual, and the capacity said 4.5 quarts. I put 4 quarts in and checked the level, and it was overfilled on the dipstick. When winterizing, I changed the oil again and put 3 quarts in to start. Level was prefect. (On level surface) Question is, do I always trust the dipstick to be accurate or should I go with the manual? I do know my engine was rebuilt and does not have the same block is came with (no place for mechanical fuel pump.). Thanks. I should add to check the level, I warned the engine to temp and then let it settle for 5 minutes before checking the dipstick.

 

[alldodge]

I do know my engine was rebuilt and does not have the same block is came with (no place for mechanical fuel pump.)

Measure the amount of oil that came out, if your only getting 3 quarts then the dipstick tube may have been changed with an automotive one. If you get 3 quarts, stick a tube down the dipstick tube to see if you get more out, otherwise see if you can remove the pan drain plug

 

[alldodge]

Also measure

 

[timharper89]

otherwise see if you can remove the pan drain plug

That is how I drained the oil. Let it sit for 20-30 minutes while I went to the store. I didn't measure what came out, but I knew I put 4 quarts in the first time, and it was over filled on the dipstick.

I also should note that I did not change the filter this time, since it only had less than 10 hours on it from when I changed it before. I know that would account for some volume. Not sure how much..half a quart maybe?

 

[timharper89]

Measure the dipstick? Not sure how I'd measure the tube though.

 

[alldodge]

12 3/16 + 1 5/8 = 13 13/16

If its 13.8 inches from the base of the tube to the top, then your good so far as measurement of the oil. The tube may not be long enough on the inside to go to the bottom of the pan, but the volume will be correct.

Could remove the tube, it's just pushed in, and held above by a clamp

 

[Scott Danforth]

I also should note that I did not change the filter this time, since it only had less than 10 hours on it from when I changed it before. I know that would account for some volume. Not sure how much..half a quart maybe?

who cares about the volume. if you had to change the oil due to gasoline contamination, you also need to change the filter.

you will need to do a few oil changes if you cant get everything out of the sump via the dipstick

 

[timharper89]

who cares about the volume. if you had to change the oil due to gasoline contamination, you also need to change the filter.

you will need to do a few oil changes if you cant get everything out of the sump via the dipstick

I changed the oil and filter from the gasoline contamination. Since then, I've only had about ten hours of use, so when I changed the oil for winterizing, I just left the filter. I also drained everything from the drain plug both times. I didn't use a pump.

 

[harringtondav]

The filter volume can take up over 1/2 of a quart. My '96 4.3 tops off perfectly at 4 qts. and a new filter. Per an old mechanic, I prefill the filter before spinning it back on. This is probably anal, but it allows the oil gallery to pressurize a few seconds earlier on start up.

 

[timharper89]

So I checked the tube out. Not sure how long it is, but it is definitely way longer than 13.8". It wraps around behind the starter before going into the block. The dipstick is over 27" and is 25" on the measurement that says it should be 26 3/4" on the photo posted.

 

[alldodge]

Is either a different year motor, or dipstick has been changed

If we deduct 13 13/16 from 24 3/4 (24 12/16) equals 11 1/16
This means it should be 11 1/16 inch to the full mark

Determine the distance to the top of the pan (was 13 3/4 in above pic) from top of the tube. Then subtract that dimension from the length of the tube. Once this is know, there should be about 11 inches to the full mark

 

[QBhoy]

Both of my old 4.3’s VP and Merc took around 4.5l of oil after running to temps and topping up once the bigger than the average filter had a say in it.

 

[timharper89]

So I finally got around to measuring the tube....major PITA. Can't be certain of great accuracy due to the curves in the tube, but I did it 3 times with around 17.5-18" of tube length. That leaves 7.5-8" of dipstick to the "full" line. Since it is less than 11", wouldn't that make the oil level higher to reach the "full" mark rather than lower?

Method I used was trace a string along the tube and measure the string. Is there a better way to measure this? It was a real pain getting my hands down to the base of the tube.

 

[timharper89]

Not sure if this is relevant but didn't think of it before. The dipstick will sometimes llif out of the tube a little on its own. Not sure how to make sure I have the right stuff to properly fill the oil level

 

[alldodge]

That leaves 7.5-8" of dipstick to the "full" line. Since it is less than 11", wouldn't that make the oil level higher to reach the "full" mark rather than lower?

Agree, it would be higher.
With that there is a dip stick error, or it is correct but has a different oil pan. If the tube does not go to the bottom of the pan then it will not get most the oil. If your willing to maybe waste some oil, suck it out an measure

 

[timharper89]

What would I accomplish by measuring oil coming out? I drained it, let it sit and added oil. How would there be more oil than what I put in? I'd rather avoid draining it again if I can help it. I've already winterized it, and I don't have a pump, so it's a bit messy to deal with.

Say it is a different oil pan, tube and/or dipstick. Is there any way to know how much oil it actually needs? Is there a way to know what block I have on the motor? Since it is not original is there a possibility that has something to do with it?

 

[alldodge]

Tell me if I misunderstood
Oil was changed and I assumed it was sucked out the dipstick tube.
If this was the case then sucking it out again would indicate how much is being removed and if only 3 qts, then this would explain why 4 overfilled

If the pan drain plug was pulled, and 4 quarts over filled the motor, then I would suspect the issue is the dipstick or pan. If draining via the pan plug then there is no reason to do it again

 

[timharper89]

Yeah I used the drain plug. I don't have a pump. Makes for a bit of a mess though.

Assuming the tube or dipstick is the problem, where do I even start with that?

 

[alldodge]

If your sure all the oil came out, and the pan is OK, then I would fill it with 4 quarts, and mark the dip stick where that comes to with a file.

Then watch the oil pressure and if its stable when running its probably the stick

 

[timharper89]

Would the oil pressure be spiking if over filled?