blowing oil 312H

[JoeB 34]

i just changed the oil in my 312H with kohler engine  i though i put the right amount in by checking the dipstick.  However when i run it there is air and oil coming out of the filler lifting the dipstick.  any advice is welcome  i hope it is bad news 

best

joeb

[Darb1964 1,093]

Drain all the oil out on a level spot. And add the recommended amount of oil, I think it's a quart and a half. I have a312-A myself and changed the oil a few weeks ago and should be able to remember the exact amount. You over filled it by a lot I would say. Maybe someone put the wrong dip. In it. You do not want to run it that over filled can do a lot of damage.

[oldlineman 1,495]

Also may want to check crankcase breather for obstruction. More likely too much oil as stated above, since it happened after oil change but not a bad idea to check breather also Bob

Edited May 17, 2021 by oldlineman

[gwest_ca-(File Mod) 11,243]

If your tractor has a row of idiot lights on the dash the engine oil capacity is 2-1/2 quarts. Without the lights 2 quarts.

 

The dipstick cap has a rubber insert that should grip the tube and hold it there. As they lose their grip with age they will pop up when started. Once started they usually stay down. The crankcase air pressure increases at start-up until the crankcase breather can exhaust the pressure. Once that happens the crankcase pressure should go to a vacuum which holds the gauge in. If you can figure out a way to hold the gauge in at startup you should be good. The alternative is to replace the dipstick.

 

Oil blown out the filler tube without the gauge sealed to the tube is normal.

 

I added an adhesive bumper to the bottom of the hood so the dipstick can't pop up on startup.

 

Garry

[gwest_ca-(File Mod) 11,243]

If the dipstick is removed every time the piston goes down on a 12hp model there is approximately 30 cubic inches of air pushed out the filler tube taking oil with it. When the piston comes back up 30 cubic inches of air is sucked back down the filler tube. This in and out cycle happens once every revolution of the crankshaft. So at an idle this happens approximately 1000 times. That is about 16.6 times per second. That is why a properly operating breather is necessary. Air is forced out but can't get back in past the check valve so the crankcase is placed under a vacuum.

 

Garry

[JoeB 34]

Thanks for the help. Now for a question that reveals my lack of experience. Where is the breather. How do I get to it to take it apart and clean it. Will I need new gaskets when I reassemble?  Are there any other things I should look for. As you see I am a novice so please imagine trying to explain to a 10 year old 

best

joe

[gwest_ca-(File Mod) 11,243]

Here are the breather pieces

https://www.partstree.com/models/51-12ke02-312-h-toro-garden-tractor-sn-020000001-029999999-1992/kohler-breather-and-vent-26/

 

The breather is positioned below the carb on the front of the engine.

 

Service manual is your friend

Garry

[JoeB 34]

thanks lots for your help  have a happy fourth

 

joe

[clueless 3,111]

If there wasn't any oil blowing out of the filler tub before you changed the oil and now there is, there's about a 90% chance you put to much oil in.

[richmondred01 2,289]

There are different lengths dip sticks. Just because it fits doesn’t make it the right one.

drain the oil, measure out 2.5 quarts and put it back in. 
once it’s in mark the dipstick.