cold weather hydraulic fluid recommendation for 743B

[jim743]

What is a good cold weather alternative to the recommended 10w30 Hydraulic fluid for a 743B? Are there any options to install a heater in the tandem pump?

 

[mrbb]

I personally stick with OEM recommended weight oils
and just run GOOD full syn oil in there called for weights, as they will but flow better in low temps and also, protect parts better, helping with start ups in normal winter temps


unless running in extremely low temps, when thinner oil might help on cold starts, but if your in any place with extreme low temps, you should be running a block heater and a battery tender, as your electric system will be taxed more than the oil at cold start ups in extreme cold(below freezing temps)

hell in very extreme temps, folks don't even shut there engines off!,they run 24/7

so as such, oil weight of OEM< still tends to be just fine!

I'd say again just run good Syn oil in 10w30 that meets the specs your OEM calls for!

 

[jim743]

I have edited my post, as it only showed on the header, that I was inquiring about hydraulic fluid.

I have overkill in the block heater department. 2 x 400 watt heater on oposite corners and a 1500 watt external heater. Occationally the machine is outdoors, and still struggles to start even thou the temperate guage is reading 135 F. I believe the problem is the -25C/-13F 10w30 oil in the hydraulic system? I believe synthetic fluid would be a huge improvement. I have read that Tractor hydraulic fluid or AW46 in a blend or full syn can be used? But also concerned that the synthetic fluid will develop leaks. Heating the pump would be a good solution. But there appears there is no spot to install an oil heater? Or even a battery blanket with all the hoses, linkages, etc. Just wonder if someone has come up with some creative sollution?

 

[mrbb]

if your engine is struggling to start with oil temps in the 135 range, I think you need to be doing a compression test, as oil that warm should not be causing starting issues

OR maybe you have possible fuel pressure issues!


as for hydraulic fluid,,
I doubt the 10w30 (I am guessing your using in the system) again has anything to do with starting, there not really related to each other IMO

When temps get low, your hydraulic system will warm as heat builds from the running motor, warming things up, and getting things flowing

what you need to do is allow things to run for a bit till they get warmed up, before working things hard!

NOW< if you maybe have any water in the system, that can cause other issues, making things work slow or struggling,

on older machines, (just my 2 cents)

yes witching to full or mix syn fluids can , have possible leaks on gaskets and seals, with the oil being thinner of sorts

BUT these worries from my understanding on syn oils, was something the OIL makers address by adding some additives to oils now, as to very early syn oils

to help prevent leaks on gaskets and seals

NOW I am NO expert on this, but its something I have heard many times from some folks I THINK know more on the matter than I do


BUT again
your OEM< fluids, have worked for yrs if not decades in many things in cold temps just tine

struggling to start, normally has nothing to do with hydraulic systems

there motor and motor oil MAYBE related
due to lower compression, or fuel pressure flow issues

same again ,as if you have water in your fuel, or poor quality fuel


BUT if your motor is warmed up to a 135 degree's
it should be starting rather easy, ,
SO I think you have other issues than what fluid to be running! you should be checking into!


ON LAST note, I do KNOW that model bobcat skid steers, have optional lower geared starters for, machine that struggle to turn over in colder temps

but doubt this would help you, as again your warmed up to a 135 degree's

so that should be l;Ike starting in warm weather IMO!

back to motor issues/fuel issues!

 

[jim743]

The machine has seen a rebuild several years ago. I did do I compression test on it last year. I was expecting a higher reading, I would have to see if I saved my notes.......220 or 240 comes to mind. They were all within 10 or 15 psi. I got onto this thought last year, thinking that when you are cranking it over, you are also turning the pumps. I had in the past bumped over the stick and engauged the aux circuit. not really noticable when cranking the engine over, but just slowing it down just enough that it doesn't seem to want to fire. In a sense, putting on the brakes. I was thinking a cold pump would create the same effect?

I have the delco 28MT starter on it that seems to perform well. I was considering the denso style reduction drive starter. Unfortunatly, could not find any infomation if the Denso style start would crank at higher rpm. Even went as far as contacting a large electric rebuilding company, but they couldn't provide any usefull information. I feel a faster cranking starter would make a huge difference.

 

[mrbb]

I am not 100% on your motor or numbers, But I I am GUESSING< that normal compression on things should be higher than what numbers you posted, I am sure others know more than me on this,

but a guess from me would be they should be closer to say 350 than 250!
I would think your local bobcat shop can tell you spec's on what they should be(or even a good shop that rebuilds like motors)

and or, in your service manual for your machine!


as for the amount of resistance on the pumps with cold fluid
I again do not think there should be enough to slow starting down

the starter I mentioned about being a lower geared high torque starter would be a BOBCAT OEM part, IF they made one for your exact machine

looking up a bobcat parts page for your machine should show both, normal and lower geared one if they had one

BUT a lower geared starter really won't spin things FASTER
it would just spin thing under more of a load, like cold fluids!, by having more torque to turn things over! not speed!
and again I am NOT claiming to be any expert here!

SO< I again would be checking compression numbers
and checking fuel pressures and flow at things

another thing to maybe consider checking would be timing

off on timing can also cause harder starting!

 

[mrbb]

also, you might find this worth reading, if your motor is a kubota V11702


https://www.tractorbynet.com/forums...00-250-psi-too-low-compression-to-run.595659/

 

[WBW]

As to your question about HYDRAULIC FLUID, I have always used synthetic ATF in my Cat 262C and never had an issue.

 

[jim743]

Thanks for the link mrbb. I did not test for compression where the injector is located, but modified an old glow plug to attach a standard type compression tester with a higher capacity gauge. I don't think that would make any difference thou? Unless there is an issue with the guage? I can recheck the valve clearance next time I have it in the shop. The timing had been checked after the rebuild. The top of the block was resurfaced. So some extra shim was added to the pump. I recall not being too thrilled with the timing procedue. I experimented with different shims, and left it where it seemed the happiest. Will pump timing greatly affect compression? How about a worn pump?

 

[mrbb]

Thanks for the link mrbb. I did not test for compression where the injector is located, but modified an old glow plug to attach a standard type compression tester with a higher capacity gauge. I don't think that would make any difference thou? Unless there is an issue with the guage? I can recheck the valve clearance next time I have it in the shop. The timing had been checked after the rebuild. The top of the block was resurfaced. So some extra shim was added to the pump. I recall not being too thrilled with the timing procedue. I experimented with different shims, and left it where it seemed the happiest. Will pump timing greatly affect compression? How about a worn pump?

I am honestly not sure if your timing can effect compression
or if a worn pump can or cannot
I am not going to say I am skilled enough to answer them things correctly and wouldn;'t want to give you any false hope or info!
I would highly suggest talking to the folks that did the rebuild on your motor about these things, or some other tech you trust and that has experience with rebuilding motors like yours, so you get the best advice to help you more here

OR maybe try starting a new thread about these exact questions or others

some times new post get more attention, with different topic's in it

However!~

I will say, some times anything is possible, but again, I am NOT skilled enough to say 100% either way

I know others on this site are way smarter on issues like this than me

sop maybe again try a new post asking t your new questions

rather than here where topic seems more about cold weather fluids
as I said, some will skip things if they don;'t think they have much to add on some thing, but will if thread is about something else
if you follow!