Foamy hydraulic fluid need expertise

[ck26]

Hello,

I just did the 50 hour service on my CK260. After doing the service, and ensuring I had the HST fluid at the right level, I noticed that it appeared to be foamy (see pic). The foam was on the dip stick after coming up to temp and checking it warm.
I stopped by my local dealer and they said if it's running fine, then it's fine. That it could be foamy just from use. I'm no diesel mechanic but I thought this was an indication of some problem (overfilling, air getting into it, etc).

What are you thoughts?

 

[oldnslo]

Did you replace a filter that is on the inlet side of the pump? If yes was it an OEM filter or some off brand? Some models of tractors are sensitive to filter used in that application.

Do you hear any growling sound from the pump if under load like lifting load on FEL? This would also indicate air leak or restriction from incorrect filter on inlet - suction side of pump.

 

[RandyT]

And don't forget that they can also be sensitive to certain THF oils. I did my first 50 hour service with Rural King branded oil and it immediately started foaming within a few hours. Switched it out for Rotella HD tractor fluid. Been fine ever since. But the Rotella T tractor hydraulic fluid is Spirax S4 TXM in a different tagged bucket.

 

[ck26]

Did you replace a filter that is on the inlet side of the pump? If yes was it an OEM filter or some off brand? Some models of tractors are sensitive to filter used in that application.

Do you hear any growling sound from the pump if under load like lifting load on FEL? This would also indicate air leak or restriction from incorrect filter on inlet - suction side of pump.

I did replace both filters (Hydraulic filter & HST filter) and they are OEM. I do not hear any unusual sounds. the machine seems to run fine. But from the little I know, I understood foaming to indicate an issue. I topped it off with Shell Spriax S4 TXM (dealer recommended). I did not do a full fluid change, just the filters.

 

[ck26]

And don't forget that they can also be sensitive to certain THF oils. I did my first 50 hour service with Rural King branded oil and it immediately started foaming within a few hours. Switched it out for Rotella HD tractor fluid. Been fine ever since. But the Rotella T tractor hydraulic fluid is Spirax T4 TXM in a different tagged bucket.

Interesting, I didn't know that. My dealer recommended grabbing a gallon of Spirax T4 and I used that to top it off. Now I'm wondering, what does Kioti use from the factory? I wonder if the top off is different fluid and maybe having a bad reaction...

 

[RandyT]

Interesting, I didn't know that. My dealer recommended grabbing a gallon of Spirax T4 and I used that to top it off. Now I'm wondering, what does Kioti use from the factory? I wonder if the top off is different fluid and maybe having a bad reaction...

The OEM oil from Kioti used to be Donax TD which is now superceded to the Spirax S4 TXM

 

[Coyote_CS2220]

Hello,

I just did the 50 hour service on my CK260. After doing the service, and ensuring I had the HST fluid at the right level, I noticed that it appeared to be foamy (see pic). The foam was on the dip stick after coming up to temp and checking it warm.
I stopped by my local dealer and they said if it's running fine, then it's fine. That it could be foamy just from use. I'm no diesel mechanic but I thought this was an indication of some problem (overfilling, air getting into it, etc).

What are you thoughts?

The photo "looks" like there is more than just foam on the surface. I might be wrong, but here is the issue.

Foam is cause by air getting into the fluid. It is unlikely that it is a chemical reaction of different Shell labelled fluid.

The air is either being added by mechanical whipping/agitation or injected directly from the engine/pumps (leaking seal or suction side air leak, maybe ?).

The problem with air bubbles in oil or hydraulic fluid is that under pressure they compress easier than the fluid and they reduce lubricity (air is a poor lubricant). Air bubbles "IN" circulating oil or hydraulic fluid is not something you want.

With the engine running and warmed up and the same foam visible in your photo, is it possible to to pull a sample of the THF from lower in the tank using a clear pipette to see if the THF is filled with tiny bubbles which float to the surface to create the surface foam in your photo?

The THF that is being drawn into the HST and Hydraulic pumps should be clear and bubble free.

Yea, the foaming does not look right to me. My THF is always foam/bubble free and for my fork lift, the hydraulic fluid is always bubble/foam free.

Keep asking the question. What is creating the foaming in the THF reservior?

BTW I use Spirax S4 in my machine.

PS.......it is also possible that when you changed out the THF, you managed to add air into the system by not draining all the fluid. The foam is being created by the circulation system clearing the added air. Keep checking the reservoir. If the foam disappears over time and you see a fluid drop on the dip stick, then this is what happened. Top up the fluid as required and you are good to go. But keep monitoring what is going on. If the foaming persists, you will need to find the reason.

 

[ck26]

The photo "looks" like there is more than just foam on the surface. I might be wrong, but here is the issue.

Foam is cause by air getting into the fluid. It is unlikely that it is a chemical reaction of different Shell labelled fluid.

The air is either being added by mechanical whipping/agitation or injected directly from the engine/pumps (leaking seal or suction side air leak, maybe ?).

The problem with air bubbles in oil or hydraulic fluid is that under pressure they compress easier than the fluid and they reduce lubricity (air is a poor lubricant). Air bubbles "IN" circulating oil or hydraulic fluid is not something you want.

With the engine running and warmed up and the same foam visible in your photo, is it possible to to pull a sample of the THF from lower in the tank using a clear pipette to see if the THF is filled with tiny bubbles which float to the surface to create the surface foam in your photo?

The THF that is being drawn into the HST and Hydraulic pumps should be clear and bubble free.

Yea, the foaming does not look right to me. My THF is always foam/bubble free and for my fork lift, the hydraulic fluid is always bubble/foam free.

Keep asking the question. What is creating the foaming in the THF reservior?

BTW I use Spirax S4 in my machine.

PS.......it is also possible that when you changed out the THF, you managed to add air into the system by not draining all the fluid. The foam is being created by the circulation system clearing the added air. Keep checking the reservoir. If the foam disappears over time and you see a fluid drop on the dip stick, then this is what happened. Top up the fluid as required and you are good to go. But keep monitoring what is going on. If the foaming persists, you will need to find the reason.

thanks for replying. This is super helpful. I'm going to run the tractor for a bit and monitor over the next few days. Hopefully it is a matter of air getting into the system and it will work itself out. I do have a manual fluid extractor, that I use for oil changes. I'll try and pull a sample with that and see if I can tell what the lower fluid looks like.