Yanmar SA424 possible water contamination in Hydraulic Fluid

[Hulaballoo]

The motor gradually dying is a typical symptom of a fuel filter that is pulling in gelled fuel - as the fuel filter becomes progressively plugged with wax and gel. Easiest to just replace the filter. Now is the time to add some serious anti-gel to the fuel tank. Having a bit too much anti-gel won't hurt anything.

50/60 degress F may not be enough temperature to deal with gelled fuel. Don't feel bad, I had some fuel gell on me in our tractor last year in spite of 50 years experience. There is no commercial test for diesel fuel gel point - called "cloud point" - although it is simple to test yourself.
Once it has gelled or has "waxed", there are plenty of articles here on TBN on what to do. Last year on mine I used Power Service 911 and followed that with John Deere TY26787 winter fuel conditioner and de-icer. Be generous with the dose. It may take a few days of near summer temperatures even with the 911. .

Regarding the transhydraulic oil. Your's will most likely be OK. Open center type hydraulic systems can handle some water because of the fluid emulsification additive and because any extra tends to end up at the bottom of the sump and filters.
Sure, take the hyd filters inside...thaw them out, check the gasket and reuse. If yours has more than one filter keep the order the same.

BTW, I used JD HyGard Lo Viscosity in my Yanmars. At one time it was recommended by Yanmar. You want to get the Lo Viscosity HyGard for your/our climate. Most of the trans/hydraulic fluids - even the name brands - do not offer a low viscosity. Yes, HyGard is miscible with other trans/hydraulic fluids. I live in the Colorado mountains and the regular viscosity JD HyGard is just too viscous for our climate.

Travelers is OK as a warm weather flushing oil, but you may flush better using a lower viscosity fluid.
If you read up on what the advertising term "compatible with" really means on cheap trans/hydraulic fluid, you will probably want to end up with a name brand trans/hydraulic fluid in your tractor in spite of the cost.
Yanmars are too nice and precision to risk for pennies.
Enjoy,
rScotty

Good stuff. I've seen that diesel 911 product, and will pick some up this weekend when I'm home. I'll also source some of the low viscosity HyGard. I'm not adverse to spending money for quality (which I thought I was with the oil I unwittingly contaminated), but for a flush I'm interested in the diesel idea. Is there any risk of running the Lo Viscosity HyGard year round? A few days of the year will hit triple digits. Likewise, is there any risk of running the regular viscosity fluid on extremely cold days, or is it just noisy and slow?

 

[Hulaballoo]

No, did you mean to call them hydraulic motors??? Or do you mean hydraulic pumps?



If you have a shop manual for your Yanmar it will have a hydraulic schematic. If you do, and want, you can post the hydraulic schematic and we can go through that with you. It will answer at least some of these questions.
Luck,
rScotty

Yes, I did mean pumps, though I also realize that there are also motors onboard. I believe those would turn the high pressure fluid into forward motion when I push the drive pedal. Kind of a compressor vane vs a turbine vane relationship, but with a different mechanism?

You reminded me that a helpful stranger gave me a flash drive with loads of awesome information on it, and I just found the info stored on my computer. Though I don't believe it contains a service manual per-se, it does have a powerpoint presentation that was probably written for service techs. I'll attach a screen hot of the hyd diagram, which I'm not very good at reading.

 

[Hulaballoo]

Once the diesel and 2-bottles of Seafoam are in the system, drive the tractor around at the 1200rpms and move anything with the controls for the hydraulics. This way, the water is captured and so is the bad fluid gunk. Then drain.

When we see Yanmars, Deeres, Cub Cadets in a bad way for hydraulics, this is our go to for cleaning the system. Both diesel and Seafoam have lubrication properties too, so nothing in the cleaning will be harsh on the gears, pump(s) or lines. Just keep the rpms low to avoid heat and friction as diesel and Seafoam are thinner in viscosity.

I'll try this very thing. Do you see any need to attempt to flush the diesel/seafoam out of the system, or just drain it and refill with a high quality (perhaps thinner) hyd fluid?

 

[Hulaballoo]

When you say it wouldn't restart, do you mean it was cranking but not starting? Or not cranking, like just a click when the key was turned to start position?

If it was cranking but not starting, likely a fuel issue. Warmer weather may or may not be enough to get fuel moving again. Regardless of what it takes to get it started (filters, anti-gels, etc.), make sure it's running on winter diesel.

If the engine was not cranking after it stalled, or cranked very slowly, then that is another issue entirely and possibly bad news.

The advice about not attempting to start after rollover is due to the risk that engine oil leaked past the rings and into the combustion chamber/swept portion of the cylinder. If this was the case, attempting to start it could cause hydraulic lock and serious engine damage. Nothing for you to worry about in your situation.

I mean that it cranks, and sputters as if wanting to start, but seems to be starved of fuel. I've got a bottle of Lucas anti-gel at the house, but may need to go with a product like Diesel 911 to clear the problem out. Hopefully this is all it is. I could replace the fuel filter as suggested earlier, but as I don't have another on hand, I may put my block heater to use, put a heat gun on low power to the fuel filter and see if I can get it to fire up. A fresh tank of winterized fuel and hopefully I can get it all out.

The hydro-lock risk makes sense. I'm familiar with the same problem on old radial engines on the downward hanging cylinders, (and on motorcycles that inexpertly attempt river crossings).

 

[bmaverick]

I'll try this very thing. Do you see any need to attempt to flush the diesel/seafoam out of the system, or just drain it and refill with a high quality (perhaps thinner) hyd fluid?

The diesel and Seafoam have no issues to flush out. JDM J20C or J20D work fine with the little residue left.

 

[bmaverick]

I mean that it cranks, and sputters as if wanting to start, but seems to be starved of fuel. I've got a bottle of Lucas anti-gel at the house, but may need to go with a product like Diesel 911 to clear the problem out. Hopefully this is all it is. I could replace the fuel filter as suggested earlier, but as I don't have another on hand, I may put my block heater to use, put a heat gun on low power to the fuel filter and see if I can get it to fire up. A fresh tank of winterized fuel and hopefully I can get it all out.

The hydro-lock risk makes sense. I'm familiar with the same problem on old radial engines on the downward hanging cylinders, (and on motorcycles that inexpertly attempt river crossings).

Te best fuel cleaner is Seafoam. Not only to clean the engine inside, also the fuel.

You might need to pull the fuel tank, clean it all out, then replace the fuel line and finally the fuel filter, fuel bowl and o-ring.

Your machine was made from 2014 to 2022. If contaminated fuel got into the fuel system, you need to clean and replace items.

 

[rScotty]

Good stuff. I've seen that diesel 911 product, and will pick some up this weekend when I'm home. I'll also source some of the low viscosity HyGard. I'm not adverse to spending money for quality (which I thought I was with the oil I unwittingly contaminated), but for a flush I'm interested in the diesel idea. Is there any risk of running the Lo Viscosity HyGard year round? A few days of the year will hit triple digits. Likewise, is there any risk of running the regular viscosity fluid on extremely cold days, or is it just noisy and slow?

Low Viscosity may sneak past some seals in hot weather, but only a little and should not be a problem. Regular Viscosity in cold weather is reluctant to be sucked into the hydraulic pump. Running dry can make the pump noisy and slow below zero F until the fluid warms up.

If the HyGard seems thin in the summer, JD recommends mixing in some standard HyGard. The Lo viscosity is the same oil with added viscosity extenders. I personally would stick to the lo-viscosity product. There's a reason JD sells it as well as using it for new tractor fill.
The exception is the front axle. There I would stick to 80/90 multiweight synthetic. It is very slow to drain and fill

Diesel to flush? Well, that is an old, old mechanics story that did begin as a common flushing procedure in manual transmissions. That was 70+ years ago when the old manual shifting tranny shelled out a component. But those old manual transmissions were just gears, bearings, and the odd syncro. They didn't have hydraulic pumps, power steerng, HST transmissions or any of the hydraulic systems that tractors have. They didn't even have filters. It might be OK. I've never seen any studies, Let us know how it works.
rScotty

 

[Hulaballoo]

Te best fuel cleaner is Seafoam. Not only to clean the engine inside, also the fuel.

You might need to pull the fuel tank, clean it all out, then replace the fuel line and finally the fuel filter, fuel bowl and o-ring.

Your machine was made from 2014 to 2022. If contaminated fuel got into the fuel system, you need to clean and replace items.

I have no reason to believe contaminated fuel got into my system, just perhaps summer diesel that had no anti-gel additive. The only other possible source of contamination is that I left the tank 1/3 full for a few months, so perhaps some in-tank condensation and the resulting small amount of water. What is it about the model years you mention that would necessitate replacement of these components?

The hydraulic fluid contamination is another story. That bucket was stored outside for a bit and has an air vent built into the cap that would allow pooled water to enter. I have no such concerns about the fuel.

 

[rScotty]

Yes, I did mean pumps, though I also realize that there are also motors onboard. I believe those would turn the high pressure fluid into forward motion when I push the drive pedal. Kind of a compressor vane vs a turbine vane relationship, but with a different mechanism?

You reminded me that a helpful stranger gave me a flash drive with loads of awesome information on it, and I just found the info stored on my computer. Though I don't believe it contains a service manual per-se, it does have a powerpoint presentation that was probably written for service techs. I'll attach a screen hot of the hyd diagram, which I'm not very good at reading.

Nice flow diagram. In the center, the thing like a cup or shallow U is the symbol for the common sump. Right above it is the symbol for a filter, and notice it is 35 micron type. Then going on up are two pumps - the circles with a triangle inside.
Somewhat higher and to the right is the HST filter I described. It is a 10 micron super filter for the HST.
The thing inside the HST box with the big arrow is the variable displacement pump that runs the HST. Lots of different ways to depict that...
Hey It looks like your loader bucket dump has a regenerative valve, that's nice.
rScotty

 

[Hulaballoo]

Quick update: I waited until the warmest part of the warmest day (a couple weeks ago now) and the tractor started up. I added an anti-gel rich fresh diesel to the tank and she's running as good as ever. As for the hydraulics; I put 1.6 bottles of Seafoam in the hydraulic tank (the rest in the fuel), checked that the level was full, then started it up. Slow, shuddering hydraulics that didn't get much better as they warmed up. Then I checked the sight glass...off the glass low. I realized that cycling the cylinders by hand had the desired effect of draining more contaminated fluid, but also required a gallon or so more fluid than the stated capacity. Oops. I made up the difference with fresh diesel and eventually it seemed to get all of the air out of the system. Everything is running great now! I'm grateful for the knowledge of this community.

Now the next step. I figure my hydraulic system is 4/5 mildly contaminated hyd fluid, and 1/5 diesel. I've warmed it up thoroughly a couple of times by pulling the kids around the neighborhood on sleds, then cycled every cylinder a few times to mix everything up. I imagine that the Seafoam has done its work right away, or is there benefit to leaving it for a bit? I plan to warm it up one more time, lift all 4 corners off the ground, drain the hyd system again, filters included, cycle each cylinder by hand again, this time I'll also try to rotate the drive motors and steering cylinders. I'll re-fill with fresh fluid and call it good.

I intend to use at least some low viscosity HyGard. Because this machine maybe working hard in summer months, I'm inclined to mix the Yanmar specified viscosity with the low stuff, perhaps in a 2 to 1 ratio. Is this overthinking it? Any reason not to mix fluids?