Oil Pressure LIght on 751 F

[Stephend]

I have a 751 F with 1440 hours, it is a 1999 model. I use Rotella 15w-40 with less than 20 hours on the oil. I change oil every 50 hours. My problem is the oil pressure light comes on when the temperature is below 30 degrees. It will go off if i idle the engine to the lowest setting with the speed level and operate the aux hydraulic switch to lower the eng. rpm even lower. Once the engine is warn the light stays off at all rpms. The oil light does not come on at all once started when temps are 40 or above. The engine does not use any oil between changes. Is my problem the wrong oil weight reange, defective oil pressure switch, oil relief valve stuck open, or What? Thanks

 

[Tazza]

Thats quite odd, the oil is thicker when the temperature is colder which should keep the pressure higher. All i can think of is there is a problem in the filter with the colder temperature causing the oil to be restricted and lowering the oil pressure. That is the same oil that i use, but its not very cold here at the moment.

 

[sterlclan]

Thats quite odd, the oil is thicker when the temperature is colder which should keep the pressure higher. All i can think of is there is a problem in the filter with the colder temperature causing the oil to be restricted and lowering the oil pressure. That is the same oil that i use, but its not very cold here at the moment.

check the sender if it is easy enough to pull you could put a guage in and see what is really going on. ive seen a bad ground act funny like that before too

 

[skidsteer.ca]

Thats quite odd, the oil is thicker when the temperature is colder which should keep the pressure higher. All i can think of is there is a problem in the filter with the colder temperature causing the oil to be restricted and lowering the oil pressure. That is the same oil that i use, but its not very cold here at the moment.

Are you sure the light is for your engine oil pressure and not your charge oil / transmission pressure?
It sould like how the trans would behave when the oil is to thick.
It can't get through the filter fast enough until the oil warms up some. As it slowly warms you can keep increasing engine speed.
Why are you using such heavy oil?
I hope you don't work in really cold temps, or that you have a heated bulding to park in.
10/30 is what is usually used in hydraulics and 5/30 for temps below 0
15/40 is like pudding at -20f

 

[nobull1]

Are you sure the light is for your engine oil pressure and not your charge oil / transmission pressure?
It sould like how the trans would behave when the oil is to thick.
It can't get through the filter fast enough until the oil warms up some. As it slowly warms you can keep increasing engine speed.
Why are you using such heavy oil?
I hope you don't work in really cold temps, or that you have a heated bulding to park in.
10/30 is what is usually used in hydraulics and 5/30 for temps below 0
15/40 is like pudding at -20f

Not to hi-jack the thread but that is what happens on my 763c with my hydraulic light. Cold weather the light comes on at anything above idle till it has run for a couple of minutes, than all is fine. I asked the dealer and they didn't seem too worried and said not unusual. I don't have much experience with this machine as of yet, and I am waiting for a manual to increase my knowledge. So! is this normal for machines to do this. The person I bought it from claims to use Bobcat oil, and I have no reason to not believe him.

 

[skidsteer.ca]

Not to hi-jack the thread but that is what happens on my 763c with my hydraulic light. Cold weather the light comes on at anything above idle till it has run for a couple of minutes, than all is fine. I asked the dealer and they didn't seem too worried and said not unusual. I don't have much experience with this machine as of yet, and I am waiting for a manual to increase my knowledge. So! is this normal for machines to do this. The person I bought it from claims to use Bobcat oil, and I have no reason to not believe him.

My 853c does this to, I put fresh 10/30 in last spring and new filters. But @ 20 far the trans light will stay on at startup with the engine at idle. after 2mins 1/4 throttle ok, 5 mins and all is normal, no more trans/charge pressure light.
Ken

 

[nobull1]

My 853c does this to, I put fresh 10/30 in last spring and new filters. But @ 20 far the trans light will stay on at startup with the engine at idle. after 2mins 1/4 throttle ok, 5 mins and all is normal, no more trans/charge pressure light.
Ken

Ken

This is almost the same as mine acts when cold. I guess this is normal for some machines ? One thing this does is make you want to let it warm up before using the hydraulics-this can only be a good thing for the machine.

 

[Stephend]

Are you sure the light is for your engine oil pressure and not your charge oil / transmission pressure?
It sould like how the trans would behave when the oil is to thick.
It can't get through the filter fast enough until the oil warms up some. As it slowly warms you can keep increasing engine speed.
Why are you using such heavy oil?
I hope you don't work in really cold temps, or that you have a heated bulding to park in.
10/30 is what is usually used in hydraulics and 5/30 for temps below 0
15/40 is like pudding at -20f

Thanks everyone for the valuable feedback. I am new to the world of Bobcat skid steers and need all the help I can get. Since the unit is used, repairs are expensive and I have limited funds I appreaciate help. I am going to switch to a 10w-30 at least for the winter and check the oil pressure with a gauge to make sure. Iwas using 15w-40 because the guy I bought it from said that was the weight and brand he used.