[Terry G]

Hi,

I have owned a 2001 Mini Mill for about a year now and have just encountered a serious problem with way oil in my coolant.

Coolant was fairly clean (just replaced it about 1 month ago) and while running a job today, the coolant started getting green / brown. By the end of the job it was pretty nasty. The coolant tank has a very thick oil slick on it. I stuck my finger in it and when I took it out it looked like chocolate pudding dripping from my finger. I've attached a picture below. That is a reflection on the thick oil slick.

I never received any alarms for low pressure. I even checked my pressure twice tonight with the mill running. Once I let it self pressurize, then measured about 9:30min before the pressure went from 40 to 0psi. I then did a quick pump manually, and the pressure only lasted about 5:30min. I may not have given it a full charge though.

I decided to pull the way covers off for the first time since I owned the machine. Last owner said he took them off once a year to clean under them.

Boy was I surprised. It was disgusting in there. There was about 3" of brown nasty coolant filled up under the way cover. The first 1/2" was a solid slick of oil that I could pick up with my hand, and the bottom inch was a solid mess of chips.

I took a few pictures and was hoping someone who has taken their same or similar mill apart could let me know if this is normal for about 1 year of use. Figure an average of 2 to 3 times a week running the machine.

To sum this long message up, this is what I am not sure on:

1. Is it possible to get that much way oil in coolant over a day or two with proper pressure and no alarms?

2. Should the area under the way covers look like this after a year of 2 to 3 times a week use?

3. Should the coolant drain out from under the ways?

4. Is it normal to have the brown oil staining around the metering blocks as seen in photo 4. These look like stains developed over a long period of time.

Thanks for taking the time to read this. I wanted to pull it apart and try to understand what is going on before I called Haas to come and take a look. We only have two guys out here and they are usually booked for a while.

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I wanted to add that last month I had a small issue with the way oil pump. It was just a loose wire and I fixed it pretty easily. Though in the process I messed with the turn dial on the plunger. I was told by Haas that turning this did absolutely nothing. So I turned it a bunch of times while I had the motor off too see if it actually did anything. Couldn't see anything going on.

I have read that this could control the amount of oil pumped into the system. If so, maybe it has something to do with this new issue? Can anybody confirm exactly what this does if anything.

Thanks!

[uli12us]

It seems that you must only add water to bring the concentration to the right level. Eventually you should use a refractometer to detect the right concentration.
If its to much bedways oil than you can use an oil skimmer. In the easiest way its only a endless hose or ring (a disc can also be used) made of polyurethane who runs slowly through your coolant and will be cleaned by a windscreen or similiar wiper.

[Terry G]

Thanks for the quick reply.

I am familiar with the oil skimmers, but oil in the coolant has never really been an issue. The oil you see in the photo I posted is pretty much from 1 to 2 days of running the mill.

I can go months and months without having any noticeable oil in the coolant. Eventually a small slick will appear and I can simply clean it up easily. It is a small machine with a 25 gallon tank and not really much room to install a skimmer. I use newspaper ever once in a while when a little oil appears.

This huge oil slick just happened all at once.

The coolant concentration should be really close. I just replaced all the coolant a little over a month ago. A refractrometer would be nice to keep the concentration spot on during refills. But since then I have only topped off the tank once.

Thanks.