How much oil pressure

DennisArrow · May 30, 2004

I have a tl 2300. I use rotella 15/40 oil. When brush hogging the unit gets pretty hot, just above the mid mark on the temp guage. When I slow down to take a break I come down from around 2400 RPM to around a thousand to let it idle the oil light flickers and then dissapears at around 1500. I put an oil pressure guage on it Saturday, when cold it is in the 65 PSI range at 1500 and above. Once warmed up this RPM range stays at just below 50 to 55 at 2400 RPM. At idle it gets down to around 20. Wondering if this is acceptable. Trying to find some straight 40 weight oil to see if this makes a difference.
Any thoughts?.....Dennis

gbirky · Jun 1, 2004

Your oil pressure regulator valve is probably opening in the 50-60psi range. When hot, it normally won't generate as much oil pressure. I work at the Mack Trucks Powertrain plant, and when we test new engines, we require only 20 psi oil pressure when hot at idle (650 rpm). 20 psi at idle should be plenty for your Iseki.

DennisArrow · Jun 2, 2004

thanks Greg..........I am not familiar with the oil pressure regulator valve.......or even if my tl2300 has this.......could you please explain.......thanks.....Dennis

gbirky · Jun 3, 2004

On my Yanmars, its nothing more than a ball and spring buried in some fittings in the engine block behind the oil filter. Its function is just to relieve excess oil pressure generated when the engine and oil are cold. I thought they were normally set at around 30-35psi, but your tractor may be different. Our Mack engines relieve at 60psi.

larso1 · Jun 3, 2004

Dennis,
On my Iseki TS1610F, a 975cc twin Isuzu motor, there are two relief valves in the aluminum casting that's bolted to the block and that the oil filter is mounted to, one relief on each side of the filter. The larger piston and spring type is the safety relief valve and relieves at 64-psi. The smaller ball and spring relief is supposed to open at a differential pressure of around 12- to 17-psi as I remember. That smaller relief is supposed to open when the filter becomes clogged and / or as the engine is set at a higher speed. Both valves can be easily removed with a wrench.

Bill in CO

DennisArrow · Jun 9, 2004

Bill.......I wonder if any others out there have mounted an oil pressure guage on a TL series and what their results are.........Thanks for your input....looked in my parts book and couldnt identify an oil pressure relief valve.......probably dont know what I am looking for though......This is an Iseki engine in the TL series............thanks for the help.....Dennis

powellfun · Jun 16, 2004

I have a TL2700 with a similar problem. After speaking with an Iseki mechanic in Hawaii, I think the problem is dilution of oil with diesel. It is most likely getting into the engine through a bad diaphragm in the lift pump. Anyone every have a similar problem?

DennisArrow · Jun 16, 2004

I agree about fuel getting into the oil someway........shouldnt be doing this after a fresh oil change and filter............perhaps I should try this?

gbirky · Jun 17, 2004

If there is fuel or hydraulic fluid in the engine oil, you should be able to notice an increase in oil level as measured with the dip stick. Check before use, and after (but let it sit for about an hour first so the oil can drain back down into the pan).

powellfun · Jun 17, 2004

I already done the oil check and confirmed a dilution. I had about 1/2 quart increase. I believe the oil pressure light is caused by a loss of viscosity due to fuel dilution of the oil, especially when hot. The only other possible dilution source would be the hydraulic pump. But I cannot see 1/2 qt. dilution of hydraulic oil causing a change of viscosity which would result in an oil warning light. I pulled the diesel lift pump and the diaphragm looks good. Since the tractor runs fine without a noticeable loss in power, the next logical source of problem is the fuel injector pump. Is there a way to perform a pressure test on the diaphragm lift pump to make sure?