PS pump, how hot is too hot?

[sloshy]

Sick of burning out my old 3rz pumps, so I through in a commodore one, just wondering what the over heating temp roughly is for a power steering pump? Is cooler the better? Or is there an ideal operating temp?

[ricky1970]

Never actually measured the operating temp of a PS pump when worked hard, but in general cooler (to a point) is better. Most of your common nitrile sealing elements have a max working temp rating of around 90degC, but you are best staying under this for long term use.

The PS pumps i do play with, mostly Vickers vane pumps off trucks, we fit viton seals as they can (and do) cook the std nitrile seals very quick. They are direct engine driven tho, so engine oil heat plays a factor.

In general hydraulic instalations, a general rule of thumb is if you can hold your hand on the resivoir, temps are good. You ain't gunna do that at much over 60degC.

Main drawback with PS setups is a patheticly small resivoir. And more oil to the system (bigger tank) or some sort of cooler arangment will help with temps, even an inline spin on return line filter placed where it will get airflow around it will help. Another general rule of thumb is to make the tank capicity 3x the pump oil flow, ie 30l/min oil flow = 90L resivoir. This is fine in stationary installs, but is obvoiusly a bit impractical in mobile situations, so you do what you can to keep heat under control when running smaller tanks.

Is it high operating temps killing it? If the rotor is picking up on the end plates it could be the pump is running to fast (slow it down, bigger pulley etc) and/or the oil breaking down (very low viscosity, back to heat??). 15w40 diesel engine oil can be good for running in high heat situations.

[PBBIZ2]

Sloshy, I have to admit I have never burnt out a ps pump before - what are you doing for this to happen?

Anyway, regarding temps, I have just gone thru the installation of a new hydraulic winch running off a second PS pump. I have measured the temp of the pump and winch motor and valve block without an in-line cooler and it was running at over 100deg C whilst only idling - suspect valve block too small for the flowrate.

I added a cooler and temps are now around the 38 deg C market after a fair bit of cycling, ambient temps were both 25 deg C. I went for a cooler off ebay which is an extruded aluminium barrel style. I was concerned about core damage as the cooler location was vulnerable. I was unable to get any cooling capacity out of the supplier - they are just a vendor, but it has both internal and external fins and is very robust. It wasn't expensive from memory - $75 delivered. Its approx 80mm outside dia and 500mm long.

When I received my second PS pump from the US manufacturer, they state the max operating temp is 65 Deg C. I think you should stick with the PS fluid as it flows well at most temps and I think anything thicker will be 'claggy' at low temps.

I measured the temps with a calibrated IR temp probe, non contact. I have not measured the standard PS pump, but would not expect it to run much above 45 Deg C at a guess as it is intermittent duty.

Hope this helps.

[sloshy]

Great info guys, cheers.

Sloshy, I have to admit I have never burnt out a ps pump before - what are you doing for this to happen?

I run a hilux with typical high steer and hydro assist and was using the standard toyota 3rz ps pump, and just a cooler behind the grill with no fan, so really at crawling speed, it wouldn't do much.

I am now running a vr commy pump with the standard remote res, but with a better cooler and thermo fan behind the cab, so it adds about 6.5m of hose as well.

The damage inside the 3rz pumps was a heap of scoring and gouging.

[11_evl]

Sloshy, I have to admit I have never burnt out a ps pump before - what are you doing for this to happen?

Anyway, regarding temps, I have just gone thru the installation of a new hydraulic winch running off a second PS pump. I have measured the temp of the pump and winch motor and valve block without an in-line cooler and it was running at over 100deg C whilst only idling - suspect valve block too small for the flowrate.

I added a cooler and temps are now around the 38 deg C market after a fair bit of cycling, ambient temps were both 25 deg C. I went for a cooler off ebay which is an extruded aluminium barrel style. I was concerned about core damage as the cooler location was vulnerable. I was unable to get any cooling capacity out of the supplier - they are just a vendor, but it has both internal and external fins and is very robust. It wasn't expensive from memory - $75 delivered. Its approx 80mm outside dia and 500mm long.

When I received my second PS pump from the US manufacturer, they state the max operating temp is 65 Deg C. I think you should stick with the PS fluid as it flows well at most temps and I think anything thicker will be 'claggy' at low temps.

I measured the temps with a calibrated IR temp probe, non contact. I have not measured the standard PS pump, but would not expect it to run much above 45 Deg C at a guess as it is intermittent duty.

Hope this helps.

do you have any pics of your setup and a link to cooler you are using??

[PBBIZ2]

Michael,

tried to paste the link, but it dropped the completed message out - operator error I suspect! Jump onto ebay, punch in 'oil cooler' and scroll down thru the list for a 'polished aluminium finned cooler, 18" long, price $125 - gone up a bit, but different vendor - AH Components is the seller - looks like a drag car accessory dealer.

The barrels have the same fin format internal in contact with the oil as they have external in contact with the air. Its a strong, fully welded assy and the heat transfer is direct. 1/2" bsp inlet/outlets from memory. Doesn't leak and would take a hell of a hit to damage it. I have mine mounted behing the winch on top of the chassis rails, in front of the radiator on a GQ.

If you have a search under RUNVA HYDRAULIC WINCH, scroll thru the pages and my build is there, but does not show the coler as it was added later after discovering the heat issue.

I can take a photos this weekend and send if you want - let me know. The photo on ebay does not really show what/how it is configured - but the barrel looks like a standard finned heat sink on an electronic board, with the fins about 10mm long and 2mm thick down the length of the body. I have clamped the body to a bridging bar cross the chasis rails, then bolted the bar to the chassis.

[-Scott-]

In general hydraulic instalations, a general rule of thumb is if you can hold your hand on the resivoir, temps are good. You ain't gunna do that at much over 60degC.

60 degrees? You're a hard man! 45 degrees is about the hottest I can hold indefinitely. Above that, either the device cools down as I hold it, or it gets to the point that I have to let go.

[Bumpy45]

In general hydraulic instalations, a general rule of thumb is if you can hold your hand on the resivoir, temps are good. You ain't gunna do that at much over 60degC.

60 degrees? You're a hard man! 45 degrees is about the hottest I can hold indefinitely. Above that, either the device cools down as I hold it, or it gets to the point that I have to let go.

Not indefinately. Put your hand on it, count to five as fast as you can, if you reach five then have to pull it away then the temp is about 60 or less.

[Guy]

In general hydraulic instalations, a general rule of thumb is if you can hold your hand on the resivoir, temps are good. You ain't gunna do that at much over 60degC.

60 degrees? You're a hard man! 45 degrees is about the hottest I can hold indefinitely. Above that, either the device cools down as I hold it, or it gets to the point that I have to let go.

work hospitality for a while .. when you start you wince picking up a plate .. after a month or two you dont even notice your skin sticking to it ..

[Turbo Tonka]

was the scoring and gouging due to heat or are you running it dry at times somehow on the trails causing the damage??

If its been too hot the seals will normally go hard or just turn to shit and there will be signs of heat with colour change in the pump body etc.

[Willy Hilux]

I went through 3 x 3rz pumps and got sick of rebuilding them with no luck. Went to a Ford XF (I think) tear drop one and no probs now, but still was getting hot. Now have a pretty large oil cooler under the tray with it's own thermo fan. With the length of line and the size of the cooler, I don't think I'm gunna have any more dramas.

[ricky1970]

In general hydraulic instalations, a general rule of thumb is if you can hold your hand on the resivoir, temps are good. You ain't gunna do that at much over 60degC.

60 degrees? You're a hard man! 45 degrees is about the hottest I can hold indefinitely. Above that, either the device cools down as I hold it, or it gets to the point that I have to let go.

Not indefinately. Put your hand on it, count to five as fast as you can, if you reach five then have to pull it away then the temp is about 60 or less.

Yeah, thats pretty much what i ment. Not hard at all, workin in hydraulic oil every day the hands quite soft.