# Hydro Fluid Question??? ON BOBCAT 743



## ramdieselsmoke

Hi i just bought a 89 bobcat 743, i am trying to find the fluid level for the hydro. i noticed a sight glass on the fluid tank. i am wondering if i should see fluid when cold or hot? right now i dont see anything in the sight glass machine is cold. what kind of 10w30 should i use? castrol? thanks


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## DGODGR

My Bobcat is not as old as yours so you may want to wait for a reply from someone who has your model before you do anything. I make sure that the sight glass (mine is on the side of the frame) has oil in it even when it's cold. Mine has a small bean in it so you can tell if there is oil (the bean should be floating). The oil will expand as it heats up. The oil will be higher than the sight glass when it reaches operating temperature. On my tractor ('06 A300K) there is plenty of room to handle that expension. I'm not sure where you are getting the 10w30 idea from. If it comes from a manual, I'm sure the answer to your questions can be found there. I use Bobcats Hydrostactic/hydraulic oil. I'm not sure of the of the ISO or SAE spec for that oil. If you have that spec you can buy any oil (dosn't have to be Bobcat oil) that meets that spec. Now that I'm thinking about it... Does the 743 come with an oil cooled Duetz engine? If so, are you talking about the cooling oil or the hydraulic oil (as mentioned in your post). If it's cooling oil I don't think I can be of much help (as if I am anyway). I had an A220 previously (an oil cooled unit w/Duetz engine) but I never had an issue with the cooling oil, nor did I ever have to add oil.


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## ramdieselsmoke

DGODGR;1006955 said:


> My Bobcat is not as old as yours so you may want to wait for a reply from someone who has your model before you do anything. I make sure that the sight glass (mine is on the side of the frame) has oil in it even when it's cold. Mine has a small bean in it so you can tell if there is oil (the bean should be floating). The oil will expand as it heats up. The oil will be higher than the sight glass when it reaches operating temperature. On my tractor ('06 A300K) there is plenty of room to handle that expension. I'm not sure where you are getting the 10w30 idea from. If it comes from a manual, I'm sure the answer to your questions can be found there. I use Bobcats Hydrostactic/hydraulic oil. I'm not sure of the of the ISO or SAE spec for that oil. If you have that spec you can buy any oil (dosn't have to be Bobcat oil) that meets that spec. Now that I'm thinking about it... Does the 743 come with an oil cooled Duetz engine? If so, are you talking about the cooling oil or the hydraulic oil (as mentioned in your post). If it's cooling oil I don't think I can be of much help (as if I am anyway). I had an A220 previously (an oil cooled unit w/Duetz engine) but I never had an issue with the cooling oil, nor did I ever have to add oil.


i dipped the tank its about 3inches below the sight glass, i just bought the machine it hasnt been used much at all in the past 7 years like200hrs. the aux hydraulic lines leak a little but there are no other leaks on the machine so im guess that is why im low on fluid. i did read you can use a type of 10w30 but no one says what brand or synthetic or not. i would like to know that. thanks jc


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## ramdieselsmoke

just went to carquest and picked up a 5gal bucket of AW 46 hydraulic fluid. so im allset


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## ryde307

From my understanding and according to the dealer we work with all bobcat hydro fluid is 10w30. I don't remember if its synthetic or not. I would say it is in the hydraulic setting.


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## ramdieselsmoke

ryde307;1008710 said:


> From my understanding and according to the dealer we work with all bobcat hydro fluid is 10w30. I don't remember if its synthetic or not. I would say it is in the hydraulic setting.


After allot of online research, i talked to the bobcat tech, he said bobcat hydraulic fluid called black gold is what should only be used in 743's. also all repair manuals as of 2008 say to use only that, its been tested and proven that 10w30 is not good enough, it breaks down so your machine over time will break down. he said if you only have to add alittle just to get through the rest of winter season aw46 is the closest to black gold you can get, ive done allot of reasearch and this is the true answer BLACK GOLD bobcat hydraulic fluid is the only stuff to use. also he said only to use the aw46 if im less then 1 gal low no more, and to have it changed as soon as i can with the black gold.wesport


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