What am I doing wrong?

[ToadHill]

The last 2 times I changed the hydro oil in my Dk35, it takes forever to fill. I pull out the dipstick, open the filler tube ,put in a funnel and start to pore. All goes well for the first 3 or 4 gallons then the stuff just backs up and burps and gurggles. It will take maybe a pint or two between burps and thats it.

Is there an air bleed that I'm missing or something.

 

[Highbeam]

Maybe leave the dipstick out of the hole. I pour through a pretty narrow funnel so there is plenty of room in the fill tube for air to come back out. Pour slower?

The good news is that it is infrequent.

 

[IslandTractor]

I second Highbeam's suggestion. Pull out the dipstick.

I've had a different problem recently with regard to hydraulic fluid that may be related. I put the tractor away and a week later checked the hydraulic fluid before starting it. The dipstick was bone dry. I muttered a bit then added about a quart of hydraulic fluid before rechecking the dipstick. It now read well over the recommended range and when I started the tractor hydraulic fluid started bubbling out of the dipstick hole. I suspect there was some sort of "vapor lock" that caused the false low reading and that I then overfilled the reservoir. This is the second time I've had trouble like this so I will now be more careful about assuming the reading is correct unless I remove the dipstick and open the fill tube cap before assuming I am getting a correct reading.

 

[Rocky Kioti]

I second Highbeam's suggestion. Pull out the dipstick.

I've had a different problem recently with regard to hydraulic fluid that may be related. I put the tractor away and a week later checked the hydraulic fluid before starting it. The dipstick was bone dry. I muttered a bit then added about a quart of hydraulic fluid before rechecking the dipstick. It now read well over the recommended range and when I started the tractor hydraulic fluid started bubbling out of the dipstick hole. I suspect there was some sort of "vapor lock" that caused the false low reading and that I then overfilled the reservoir. This is the second time I've had trouble like this so I will now be more careful about assuming the reading is correct unless I remove the dipstick and open the fill tube cap before assuming I am getting a correct reading.

I also read bone dry or close to if I just check dip stick after tractor sits for a week or so. I found I have to take out and recheck. So far has worked everytime. Found this out when I did fluid change and knew there was the correct amount of fluid installed. Vapor lock maybe.......... Don't know

 

[Highbeam]

After just replacing my hydro filter mount bracket (argh) I had to add a couple of gallons to come up to level. I very much noticed that the dipstick reading was not consistent.

My theory is that the really good dipstick seal is so good that it pushes air down the tube and pushes oil out. The dipstick is pretty short and takes its reading from within the tube rather than from the sump as is typical with a pickup truck engine.

Sooo, I check it a few times and would get different readings until eventually it levels out.

Maybe temperature of this air pocket makes it expand and contract to push oil out of the tube or something.

 

[IslandTractor]

I'm glad to hear I am not the only one with inconsistent dipstick readings. Multiple measures seems to make sense especially if it is reading unexpectedly low.

 

[glmf]

ditto for me on the inconsistent readings, just went from no oil to way high in no time. Another thing is the oil is so hard to see on the stick, seems though I read on here somewhere about a Caterpillar oil dye you could add to the oil to make it more visible,,,anybody got a line on where to get some of that stuff?? And yes, having the fill cap off, seemed to make the readings more consistent.

 

[ToadHill]

The dipstick is out when I fill the Hydro unit.