milky hydraulic oil

[tylermckee]

Long story short we had our dealer out to CHANGE the hyd. oil in an excavator, and they didnt change it, they ran the old oil through a filter system they have and pumped it back into the machine. 1 day later we notice that the oil is very milky, looks like a brown/green milk. dealer so far wont actually come out and say that they f***** up, but they sent a guy out to 'flush' the system today and after an hour of use the oil looks almost as bad as it did. obviosly they didnt get everything out of the system, but what do they actually have to do to remove ALL of the contaminated oil from the machine. We have oil samples that are goining out for analysis tomorrow so we will be able to get a rough number of what and how much mater or whatever got in the system.

-What does it take to remove all the bad oil?
-what kind of long term damage can result from this? probably ran the machine ~10 hours, 5 of those hours with a breaker on.

[Kgmz]

What did they do to flush the system?


It is very hard to get the water out of hydraulic fluid. Sometimes can be removed with water absorbing filters in the filter cart. But you have to do it over and over again and keep changing the filters because they can't capture all that much water. Then you run the machine, cycling everything to get the contaminated fluid into the reservoir that was in the lines, cylinders, pump, etc. And then run all the fluid in the reservoir all over again, and again.

But the best thing is to drain all the oil out and start all over again with new fluid in the reservoir and the running everything to get what you could not drain into the reservoir and then running it through the filter cart. And the very best thing is to drain all the fluid out and then flush the system with a very light viscosity fluid and then drain and dump the flushing fluid. Then fill with your normal fluid.


I am wondering how the water got into your fluid. Could be that their filter cart was contaminated somehow, old filters with water in them, etc. Or it could be that the water was already in your system sitting in the bottom of the reservoir, and that when they ran the fluid through the cart it got emulsified into the oil and they did not have a water absorbing filter in the cart.


Depending on how much equipment a company has I recommend that most get their own filter cart. We bought our Parker filter cart a few years ago when our old excavators oil got contaminated with water. Still not sure how it happened, but I think the water was from condensation in the tank as it had been sitting unused for quite awhile. When I found out the cost to clean the fluid and system from the dealer, I decided it was better to invest the money in something I could use over and over. And since we own over 10 pieces of equipment that have hydraulic systems it has been well worth the investment.

Forgot to add we paid about $1100 for our cart, and I see now that they are selling for around $1400 now.

[John C.]

At this point the only way to get it out is to dump is all. That means dumping the oil from the bottom of the reservoir, taking the suction hose from the pump and draining that out and taking as many hoses loose and flushing them out as possible. You will still need to refill and run the system and then flush again to clear the cylinders, motors and coolers unless you go for a total teardown. I've done it both ways. If there is no metal I might just flush and take my chances. It may also depend on what the stuff actually is. It might have come from marine or aircraft use and not be compatible with your machine's system.

I would never run a high performance hydraulic system on any oils that are not specifically recommended by the manufacturer.

I take it that you caught the issue before running the machine for much time. Taking the oil samples is great because you now have an actionable claim against the dealer that did the deed. Push for everything you can and get an attorney on retainer for possible legal action. The fact that the dealer went for another flush instead of doing what was proper indicates their idea of the solution is somewhat less than what may be needed.

[rino1494]

Our one dozer had milky hyd fluid. We drained the tank and disconnected the hose on each cylinder one by one and we hooked up a air chuck to it and blew back through the tank. Changed the filter, filled up with fresh oil and now the sight glass on the hyd tank is crystal clear.

[tylermckee]

They drained our machines fliud into a 'clean' oil drum, then ran it through their filter cart into the machines tank. they have also ran 2 other machines oil through their filter after they did ours, and they say they didnt have the same problem.I think they had something in the drum, another kind of oil or water. we caught it within 8-10 hours.

When they came back to fix it they did 'flush' the system, but i dont know exactly what his procedure was.

As of now they have our machine at their shop, not sure what their plan of attack is yet. they seem to think something with the machine is causing the issue, but i'm having a hard time believing that when the oil that was in the system had 3,000 hours on it and looked great.

[mrnick777]

we had a bobcat withthe same problem and flushed it through the aux ports

[Catpower]

About 30 something years ago had that problem when exchanging hydraulic equipment with a friend. Was told years later that when you mix John Deere hyd oil with ( Ford hyd oil) it will turm milky! Is this still the same when mixing hyd oils? It amazes me that places try to say we didn't do anything wrong. Why they would let it go out the door or say that they are finished with it when they aren't?:beatsme What do they figure that we aren't going to notice it?

[Johnsoils]

A PAO synthetic hydraulic fluid will not emulsify typically. I've had problems with conventional oils in large air compressors and hydraulic systems. After switching to AMSOIL, I've been able to leave the machine down overnight and drain the condensate/water off the bottom of the crankcase or tank.

Another good maintenance practice is to use a desicant breather on your hydraulic system to filter out both contaminates and moisture. Moisture enters the hydraulic system through open reservior breathers or vents. We had a lot of problems with industrial gear boxes here in NE Iowa in the humid summer months. Since installing the desicant breathers and AMSOIL, no more moisture or maintenance issues. Please feel free to contact me if you need vendor information on the desicant breathers or AMSOIL.

[Durette]

There's no replacement for actually CHANGING the fluid. Your oil can get coked (partially burnt) because these systems can run up to 200 F. Absorption of air and contamination with water only make matters worse. Petroleum oils form acids when contaminated like this, and it forms acids which can eat your seals, valves, and metal parts.

Yeah, it costs a lot to change the fluid, but your seals and system will thank you.

[Johnsoils]

I agree that if your fluid is contaminated and/or oil analysis shows that it needs changed that this is the only option. Synthetic hydraulic fluids will stand up to temperatures way above 200 F. If you want to see some spec sheets on synthetic hydraulic fluids let me know. I would be glad to send them to you. Here in Iowa a newer problem with hydraulic systems over heating is the new air planters that the farmers use to plant corn and soybeans. These planters are huge, 24-rows or more. The air blower motor is powered by the hydraulic system and man do they get hot. Several of the farmers have switched to AMSOIL synthetic 5W-30 tractor hydraulic/transmission oil and dramatically dropped their hydraulic system temps. They are also able to run the fluid longer, as it is not breaking down or coking under the extreme operating conditions. Also, AMSOIL uses a full-synthetic base stocks, the best in the industry. This higher TBN base stock has no parrifin, sulfur or nitrogen molecules in it when it's new. These contaminates are common in new conventional petrolium oil, so when you add heat and moisture you have acid formation right off the bat. AMSOIL's full synthetic oils helps combat acid formation. Each AMSOIL product is formulated for a specific application and engineered for peak performance, reduced wear and extended drain intervals.

The AMSOIL ATF was tested to 500 F and it would not give up. Finally the third party testing service called of the test. If your having short oil life caused by high operating temperatures and acid formation. I'm sure that AMSOIL synthetics could help you out. See my web site (**************.com) for more information on the products and data sheets, or drop me an email and I'll get the information to you, or call you. Providing knowledge and documentation on AMSOIL product performance is what I like to pass on to folks. I'm here to help if people are having problems, or just what some information to gain some knowledge on synthetics, greases, or filtration. If it turns and burns, I'm interested. Thanks, John

[Durette]

I agree that if your fluid is contaminated and/or oil analysis shows that it needs changed that this is the only option. Synthetic hydraulic fluids will stand up to temperatures way above 200 F. If you want to see some spec sheets on synthetic hydraulic fluids let me know. I would be glad to send them to you. Here in Iowa a newer problem with hydraulic systems over heating is the new air planters that the farmers use to plant corn and soybeans. These planters are huge, 24-rows or more. The air blower motor is powered by the hydraulic system and man do they get hot. Several of the farmers have switched to AMSOIL synthetic 5W-30 tractor hydraulic/transmission oil and dramatically dropped their hydraulic system temps. They are also able to run the fluid longer, as it is not breaking down or coking under the extreme operating conditions. Also, AMSOIL uses a full-synthetic base stocks, the best in the industry. This higher TBN base stock has no parrifin, sulfur or nitrogen molecules in it when it's new. These contaminates are common in new conventional petrolium oil, so when you add heat and moisture you have acid formation right off the bat. AMSOIL's full synthetic oils helps combat acid formation. Each AMSOIL product is formulated for a specific application and engineered for peak performance, reduced wear and extended drain intervals.

The AMSOIL ATF was tested to 500 F and it would not give up. Finally the third party testing service called of the test. If your having short oil life caused by high operating temperatures and acid formation. I'm sure that AMSOIL synthetics could help you out. See my web site (**************.com) for more information on the products and data sheets, or drop me an email and I'll get the information to you, or call you. Providing knowledge and documentation on AMSOIL product performance is what I like to pass on to folks. I'm here to help if people are having problems, or just what some information to gain some knowledge on synthetics, greases, or filtration. If it turns and burns, I'm interested. Thanks, John

I'll agree AMSOIL is the best there is. I use their TSO 0w30 in my car. I used to work at NAPA, and I sold stuff from their whole line. For a while I actually bought the stuff directly from their distribution center in Orlando. Unfortunately, not everyone uses good synthetic fluids. All people see is the short term benefit of using cheap dinosaur juice, and they don't sit down and do the math. Good synthetics offer longer equipment life and longer change intervals; you'd be stupid to do anything else.