Why 5W30?

[Frank Sorbello]

Was wondering why Power Trac uses 5W30 motor oil in the hydraulics. Why wouldn't you use hydraulic fluid for hydraulic pumps, motors etc... Wouldn't the Robin engine start easier in cold weather with a load using hydraulic fluid vs motor oil.

Thanks
Frank

 

[mikehaugen]

I can't help you much with an explanation but I will say that it is not that uncommon. At work we have industrial hydrualic units and some spec ATF, some sae 30 motor oil, and others spec different grades/viscosities of hydraulic oil. My bunton mower specs 10w40 for the hydraulics. I don't know the reasons, I just do as I'm told. :confused3:

 

[MossRoad]

The hydraulic fluid in my old IH2500b was equivalent to 10. It was not multi-viscosity. It was stuck at 10.

5W30 starts at a 5 and increases to 30 as it heats up. Therefore, 5w30 is easier to push through the pumps when its cold than straight hydraulic fluid is. And it won't push past the seals as easy once its hot. At least, that's my understanding of it.

 

[Gary Fowler]

This sort of reinforces the idea of using Universal Transmission/ hydraulic fluid since so many different brands spec different oils and likely as not, most of the components are pretty much identical.

 

[MossRoad]

I think if engine oil works for the hydraulic system on the Power Tracs, that's what is prudent. Why? Because its available everywhere and no confusing specs to deal with. Has anyone heard from any of the hydraulic systems manufacturers as to what's best?

 

[ponytug]

Just FYI: My 1445 says 10W30 or 10W40.

I would like to offer some information that may help clear up the viscosity issue, since it has come up more than a few times; 5W30 oil must pass both the specification for a 5 weight winter oil (W), and for a 30 weight oil. In common terms, it flows like a 5 weight winter oil when cold, and a 30 weight oil when hot. The standard temperature for measuring viscosity is 212F.

A 10 weight oil is different from a 10W oil, since the latter must meet the specifications for winter (i.e. cold) flow.

Basically moving from a 5W to 15W oil makes no difference at the low temperature end, and a slight difference at the warm end. Moving from a 30 weight to a 50 weight oil almost doubles the high temperature viscosity (12.5 to 21.9cSt). So, moving from 5W30 to 15W30 should have no effect. 5W30 to 15W50 should double the high temperature viscosity, while leaving the low temperature viscosity unaltered. I can confirm that moving from 10W40 to 15W50 had no effect at low temperature, and a modest effect at high temperatures.

Broader ranges, e.g. 5W50, require the use of large amounts of additives, primarily viscosity enhancers, that tend to breakdown over time and shear, reducing the performance of the oil, so these oils may lose viscosity faster than a 15W30 oil, assuming that you only need a 30 weight oil when hot. YMMV...

Finally, in principle a 50 weight oil will take more horsepower to pump due to the increases in viscosity, and it will heat up faster due to the internal resistance. Depending on the pumps and motors, it may deliver more HP by having reduced fluid leakage by the pump and motor seals.

On my PT 1445 neither effect seems grossly observable against the background of variable air temperature and workload.

If you want to know more, there is a nice table at Motor Oil Viscosity Grades Explained in Layman's Terms

All the best,

Peter

 

[Frank Sorbello]

If you drained your hydraulic tank and went to a synthetic oil, would that help with starting in severe cold weather?

 

[KMA]

Oil and hydraulic fluid are hotly contested topics... I started a thread years ago that may address some of your questions:

http://www.tractorbynet.com/forums/power-trac/116623-best-synthetic-hydraulic-fluid-money.html

I went with Rotella T Synthetic 5w-40 due to cost and previous positive experiences with the product. It may help slightly in cold weather starting, but I'm not sure it would be enough to justify the additional expense. IMHO, you would want some other benefits in order to make the switch. Good luck!

 

[RalphVa]

Hydraulic oil is plain 5w5 oil. The 5w30 will be the same as hydraulic oil at low temperatures.

In our commercial dewaxing plants we had big rotary vacuum (on one process) and rotary pressure filters (on another process). Both used commercial hydraulic systems to drive the rotating drum and to provide variable speed. Our mechanics just used multigrade motor oil in them. At that time I worked, it was 10w30. The 5w30s didn't come out until we learned how to make near synthetic and synthetic oils.

Synthetic oils WILL NOT have very many additives mentioned by the person above.

Ralph

 

[ponytug]

Kevin's thread was very informative to me, and helped me think about when to change the oil and what to replace it with. Having decided that viscosity additives have a limited lifetime, I also drained my hydraulic tank and when it was drained, the fluid was significantly less viscous than the 10W40 that had been going in.

Given the lack of difference in low temperature performance between 5W and 15W, I went with Mobile 1 15W50 full synthetic oil (Walmart, on sale). As noted above, 15W is no different at low temperature compared to 5W, but 50 weight oil has some higher temperature viscosity performance advantages in theory.

In practice, the steering is a little stiffer with 15W50 compared to 10W40 when cold, which suggests that specifications may not fully capture actual usage temperatures. :laughing: Otherwise, I can't see any effect. If I were doing it again, I am not sure I would go the synthetic route, but it depends on how well and how long the viscosity holds up. Just for the record, a really cold start for here is 32F, but the PT1445 cranks right over and starts right up. The engine runs Delo 10W40

It was great to see the bottom of the tank and see that it was completely clean. (Hurrah for regular filter changes!) Whether it is worth the cost ($18/gal x 20 gallons) is a personal decision.

All the best,

Peter

Oil and hydraulic fluid are hotly contested topics... I started a thread years ago that may address some of your questions:

http://www.tractorbynet.com/forums/power-trac/116623-best-synthetic-hydraulic-fluid-money.html

I went with Rotella T Synthetic 5w-40 due to cost and previous positive experiences with the product. It may help slightly in cold weather starting, but I'm not sure it would be enough to justify the additional expense. IMHO, you would want some other benefits in order to make the switch. Good luck!

 

[woodlandfarms]

Peter, how often are you changing your hyd oil (at that price, I hope not often).

For me my PT tends to blow the occassional hose and I say I run through a case of 10-40 Chevron costco cheapo a year. I mulled over putting fancy stuff in (I have fancy stuff in the engine) but didn't feel the benefits in the hydraulics outweighed the cost.

 

[J_J]

Was wondering why Power Trac uses 5W30 motor oil in the hydraulics. Why wouldn't you use hydraulic fluid for hydraulic pumps, motors etc... Wouldn't the Robin engine start easier in cold weather with a load using hydraulic fluid vs motor oil.

Thanks
Frank

Simple reason is that it works well and has been working well for about 20 years.

Is there any better oil for your climate, maybe if you tested them all.

Just about any mineral based oil will work including some synthetics fluids. Just have to find a fluid you like. Price also makes a big difference.

My hyd tank holds about 20 GPM of 10W-40 motor oil, so changing out that much fluid from a $4 a qt to $10 a QT could get expensive.

 

[ponytug]

Carl,

It was the first time in six years. I hope that this fill will last at least six years. I would have done it sooner, but I was fence sitting on the regular vs. synthetic oil. Part of the impetus was that I cross threaded the filler cap for the tank at around 300 hours and I didn't discover it until after power washing the tractor. While I couldn't ever see anything in the oil, I was concerned about what might be in there. (Apparently nothing)

With various "issues" that the tractor has had I probably put in three gallons of top up oil over six years, of which two gallons were a single incident (motor seal blow out) in the first six hours of tractor use. I have the vent from the automatic brake circuit routed back to the tank. It used to leak a small amount every brake cycle. PT has a fix for it, supposedly on all of the newer machines.

I do install the oil filter fully filled, so I have probably added 2-3 gallons (12 filter changes) worth of oil there. I also have half a dozen high strength magnets on the oil filter to trap any metal debris going through the filter. After I change the oil, I move the magnets to the new filter.

So far, I haven't blown any hoses, though I have had more than a few start weeping.

All the best,

Peter

Peter, how often are you changing your hyd oil (at that price, I hope not often).

For me my PT tends to blow the occassional hose and I say I run through a case of 10-40 Chevron costco cheapo a year. I mulled over putting fancy stuff in (I have fancy stuff in the engine) but didn't feel the benefits in the hydraulics outweighed the cost.

 

[woodlandfarms]

So you change your large filter every 6 months? How many hours are you putting on it? I do once a year and am probably 100 to 150 hours a year max.

You should see Ken Simolo's magnet setup. He sent me one that I have yet to install (don't want to take the tank apart quite yet). When I do I am going totry and figure out a tank temp guage and oil level sight.

 

[ponytug]

Dear Carl,

I'm a slave to the recommend service intervals, such as they are. I change it every 50 hours, so yes, about twice a year.

I love Ken's magnet setup. Since it works on the full flow, I think that it is way better than mine, but it hasn't made it to the top of my do list, yet. I keep thinking that I ought to put a full flow filter on the PTO return to tank line to do a full filter on the oil, when it isn't being used by the PTO, or perhaps on the PTO line with a cross connector when not using the PTO line. Still in the concept stage....

All the best,

Peter

 

[woodlandfarms]

Keep me in the loop on your concept. My PT has two Hyd filters The big boy that runs the tram (OK, this is a mystery to me as the tram is a closed loop system, right? so not a lot of oil flowing?) I guess I am wrong on that as it has the 1" Hydro lines coming and going.... Probably pulling more oil than I think....

I also have a High Pressure filter on the lift tilt dump circuit but no filtering for PTO.

 

[ponytug]

Carl- I think that your "big boy" is in the inlet to the makeup oil to the tram, i.e. the charge pump. It is large to have low cavitation under the vacuum conditions of cold start up charging. The other fine filter is one I would like to have and is a fine filter on the rest of the oil via the lift/steering/curl circuit. Based on my knowledge filtration, I think that it is a toss up whether repeated 30 micron filtration is better than low flow 2 micron filtration. The PTO filtration has the advantage of high volume polishing, while the lift/curl/steering circuit has the advantage of low flow.

All the best,

Peter

All the best,

Peter

 

[woodlandfarms]

sorry on the hijack, but just to be clear. The filter on the tram pump is pretty worthless, right? not much oil (relatively) goes through that system. The PTO of course would be the best, right?

 

[MossRoad]

I'm gonna say right, and wrong. Its not worthless if you consider it is the only thing protecting the entire tram circuit, which is the variable volume pump and 4 wheel motors. As I understand it, that is essentially a closed loop system with makeup oil coming from the tank, through that filter and into the charge pump inside the variable volume pump. It does not filter the PTO circuit. On the 400 series, that is the only filter.

 

[ponytug]

As MR points out that one filter protects the most expensive components on your tractor, which I think is worth something. In addition to the tram (variable volume pump), you have the four wheel motors, and that is a pretty expensive set. On the 18XX series, the motors have case drains that return some oil back to the main system. Carl, I believe your 1850 is older, and has the extra filter. Terry once mentioned to me that they didn't feel it was useful to have the extra filter in the 18XX series. I can't recall the reasoning. Possible rationales might have been power loss and the fact that the case drains return filtered oil to the main tank.

All the best,

Peter

I'm gonna say right, and wrong. Its not worthless if you consider it is the only thing protecting the entire tram circuit, which is the variable volume pump and 4 wheel motors. As I understand it, that is essentially a closed loop system with makeup oil coming from the tank, through that filter and into the charge pump inside the variable volume pump. It does not filter the PTO circuit. On the 400 series, that is the only filter.