Interested in opinions about oil pressure

Dave H (MI) · Nov 17, 2015

This is on my CIH 1660 combine with the IH diesel engine. Just had the engine rebuilt this past summer after an oil issue.

First time actually working the engine today...I shelled some corn. At cold startup the oil gauge goes to the halfway mark at idle. I noticed today after about an hour of use that if I take it back down to idle the gauge dropped way over to the left in the red area. Oil warning light works and it did not come on. Shut down right away, let it cool down a bit and checked the oil, engine still warm. Looked a bit low but I cannot swear by it because the oil is really clean. There is oil on the dipstick but hard to tell how high on the dipstick. I added two quarts, one at a time, checking pressure and this did bring the pressure up above the red (at idle). Pressure on gauge at full throttle is just above the halfway mark cold and just below it hot. Remember, the oil warning light never comes on. I see no smoke, no sign of leakage. I have a few ideas of my own, just wondering if the more mechanical types here might have some ideas as to whether I have a problem and where it might be?

Bob Harvey · Nov 17, 2015

No help at all, but, any oil pressure is good - non, not so much.

IA Roy · Nov 17, 2015

Check the pressure with a mechanical gauge. The combine instrument cluster gauge or the sending unit may not be accurate

J.Wondergem · Nov 17, 2015

You might try another gauge to compare it with. Ten pounds to each thousand RPMs will work.

2510Paul · Nov 17, 2015

100% agree with IA Roy. You did not describe the oil issue you had in the first place. If your instrument grade gauge also shows low pressure at idle, I would wonder if the pump was damaged and is now less efficient and hence lacking at low idle. Just my thoughts. Paul, La Crosse, WI

Secret Squirrel · Nov 17, 2015

We used to have lots of problems getting a correct sender from our local dealer. Went to a different dealer, and received a different unit and the gauge read better. I asked the first dealer about the differences. Their answer was "this is what we sell." They believed because it would screw in that It would work. The second dealer was more precise, asking for serial #s etc.

rrlund · Nov 17, 2015

Yep,use a test gauge. My White has a gauge and a light. The gauge started only working intermittently but the light goes off after startup. I changed the sending unit,but it didn't help. A test gauge shows 30 pounds of pressure.

Tom-NoCenTX · Nov 17, 2015

As others have ask --- What was the oil issue before engine work?
What brand and weight oil are you using?
What brand oil filter?
What do you mean by "rebuilt"?
Tom

Princeton Bill · Nov 18, 2015

With the problems you have had and the expense you have had I'd drain the oil and refill it to what the manual calls for and get a good mechanical gauge like others have suggested. That will assure you it has the correct amount of oil and exactly what pressure the pump is putting out. After what you have experienced with this motor I'd be nervous too about how much pressure you have. Always check the oil every day before you start harvesting. When the engine is cold you get a more accurate reading on the dipstick. Park it so the motor is "level" that also gives you a more accurate reading. I'm not trying to be a wise guy, but with combines checking that oil every time before you start it is very important.

Mike M · Nov 18, 2015

I too would now be wondering what the original issue was before and if it did not get fixed ?
Get on the phone asap with who did the repairs and discuss this problem and if they say keep running it ask if they will stand behind it if it blows up.

Indiana Ken · Nov 18, 2015

You imply that the problem went away after adding two quarts of oil. That could suggest a problem with the oil pump pickup tube. If it is loose at the pump or cracked it could be allowing air to enter - adding the oil covered the area preventing air from entering. To check I would drain the oil to the add mark on the dip stick and verify the problem returns, than add oil to verify the problem goes away. In addition verify that the dip stick reading correlates with the correct fill amount per the manual.

Assuming your in dash oil pressure gage is electric it depends on a voltage regulator to supply a controlled voltage to it and the other dash instruments. A problem with this regulator or your charging system/battery could be causing the gage to read low at idle.

The warning light is just that a "warning", typically set very low indicating near zero oil pressure.

01gentdc · Nov 18, 2015

don't know the answer ,, but different oils will effect oil pressure ,,.I always used rotella in my 391 f -600 grain truck ,, guage was up on the 80 percent side , and even hot it varied less than 5/8s on the guage ,. had a guy do a tune up and oil change , he put o-reillys oil in it and the pressure was down around 40 percent..i have a DC Case , that carries 20 lbs at start up , as it warms up wide open it barely has 8-10 lbs ,, at idle it barely bounces the guage,,. another DC carries 35 lbs , my 800 Diesel carries low oil pressure too . I am told that perhaps the cam bearings are worn ,so far so good,,. my 4020 only carries 25 lbs cold,. and is less than 20 lbs ,.. most important in your problem ,, is what history occurred in this motors story ,,

Dave H (MI) · Nov 18, 2015

I agree with you 100% Bill. Based on the other replies this is the course of action that I had already decided on. While I appreciate the interest of certain responses, and while I don't want to sound like a jerk, I cannot at this time discuss the repairs on an open forum. That is just the situation at present...end of discussion. I am going to remove all the oil currently in the machine and replace it with oil as specified in the manual at the quantity specified in the manual. I will then put a mechanical gauge on it and check pressure cold and hot. Appreciate all the comments and ideas and will post back when I know something.

Russ from MN · Nov 18, 2015

I have drilled very small holes in a dip stick so I can see the oil, but you need a drill press and a very small drill. But, you have another problem, and I think others have given you some good ideas.

dwag · Nov 18, 2015

Be nice if you could look at the old crank brgs and see if they are stamped .010. Had a Deere once that had std brgs on mains that were undersized. You should have 45/50# at startup cold idle or wide open.

37chief · Nov 18, 2015

On a recent rebuild you should have good pressure. I wonder how good the oil pump is. I think you are doing the right thing by changing the oil, and starting out fresh. We all like to see good oil pressure. I had a Ford with a 460. It had almost no pressure at idle, a little more running. The truck made several trips from California to Lewistown Montana, and years after. The old chevy 6 motors had no oil pressure to the rod bearings for many years, and seamed to be ok. I guess what I am saying as long as the oil is getting to the bearings the motor will probably last a long time, if the rebuilder will not stand behind his work, and do anything about the problem. Stan

Dave H (MI) · Nov 18, 2015

One of the reasons I want to change out the oil is that I went thru the trash and can only find 10W30 jugs. This would be OK if I was running in temps below 30 degrees, otherwise the manual says straight 30W. We absolutely check the dipstick each morning (RELIGIOUSLY!!!) and I also climb up and pull it randomly thru the day. I no longer have any budget for negligence...but I digress. Yesterday it was 60 degrees here and she was working hard. I am likely to finish in over 30 degree weather next week. I want to make sure there is 30 weight oil in there and a change out is the only way. I have a half dozen older tractors that do next to nothing and are not so fussy about their oil so I can reuse the stuff I drain out.

sotxbill · Nov 18, 2015

The oil pressure may be perfectly fine. half way running is ok... in the red when reved up is NOT okay.

In the red at idle may or may not be okay, but if the oil light is working and staying out at idle, I would assume that the pressure is very good and okay. The red light will be set for just below normal idle pressure and its telling you that your okay. It will NOT put out 50 lbs of oil pressure at an idle and NEVER would.

As others have said.. check for correct type of oil for the temperature your operating in. Also check for "extra" oil where diesel fuel is getting into the crankcase and diluting the oil. This can cause the bearings to fail. If the oil level keeps going up, your getting either diesel or hydraulic fluid into the crankcase.

pete 23 · Nov 18, 2015

The old chevy you referred to had 14 psi oil pressure to mains etc and the rods were fed through a pressurized dipper system. Talk about engineering. GM had a tool to align the nozzles spraying those dippers. No way of knowing how much pressure the rods actually received with a spray of oil coming at them when that engine was turning over. Chevy claimed a lot of pressure due to the dipper collecting that spray of oil, but was not unusual to knock out a rod bearing. Had a couple of those engines.

Den N Ms · Nov 18, 2015

Dave,I have seen an oil galley plug left out on the front of a engine during a rebuild cause the same problem as you are having.It was ran that way for a couple of years till the timing cover was taken off and the plug was found to be missing.Replacing the plug solved the oil pressure mystery.

the tractor vet · Nov 18, 2015

Well untill ya put a knowen GOOD test gauge on it and check NOBODY knows for sure. BUT on a 400 sires engine you should have really good oil pressure above 60 psi and no lower then around thirty psi hot at and idle Main , rod and cam bearing Clearance along with the out put of the oil pump gives you the pressure . Now if say someone at some time left out a galley plug or a piston cooling jet was missing then the pressure will be down . So in other words if bearing clearance is at the far end of spec's and the oil pump is getting to far out of spec.'s and also you choise of oil weights there is something not wright with this engine or your gauge . Now wheather the guy that did the engine did it correctly and checked every detail with mic.'s and plasta gauge , made sure that all galley plugs were installed and all cooling jets were in place installed new cam bearing and FIT the cam to the bearings . I have no idea as i did not build the engine I have seen way tomany socalled engine rebuilds that people just slap a kit in them and check nothing and call it GOOD . A good 400 sires engine will peg the gauge and be better then half way up at idle HOT .

37chief · Nov 18, 2015

Back around 58, I spread the rod dipper a little open on my 34 Chevy to make sure it got a little extra oil. When I was 16 I guess I was trying to outsmart the GM engineers. Stan

MARK ROBKE · Nov 18, 2015

The 1660 that I ran a little bit this fall read just over half way,warmed up at full throttle and maybe a 1/4 way over at low idle.But------ check it with a manual gauge-then you will know what your actual pressure is.Don't guess that the gauge is perfectly accurate.Those gauge sender units like to fail a lot.Also an electric gauge can have poor connections somewhere and give false readings.It would also be better to idle above 1000 rpm to get better fan speed for cool down.Don't change your oil to straight 30w.10w30 is 10w when cold and 30w when hot.It makes sure oil is flowing everywhere quicker when the engine is cold.If anything-use 10w40 Rotella or the Chevron brand 10w40 . Then you will have 40w when the engine is hot.Oils are way better improved since your engine was new and all oems will tell you 10w40is better than 30w.Mark

Princeton Bill · Nov 18, 2015

With the problems you have had and the expense you have had I'd drain the oil and refill it to what the manual calls for and get a good mechanical gauge like others have suggested. That will assure you it has the correct amount of oil and exactly what pressure the pump is putting out. After what you have experienced with this motor I'd be nervous too about how much pressure you have. Always check the oil every day before you start harvesting. When the engine is cold you get a more accurate reading on the dipstick. Park it so the motor is "level" that also gives you a more accurate reading. I'm not trying to be a wise guy, but with combines checking that oil every time before you start it is very important.

Russ from MN · Nov 18, 2015

If the oil pump is sucking some air wouldn't that cause foaming, and that would cause low oil pressure?

Indiana Ken · Nov 18, 2015

Russ, Yes if the pump was sucking air the oil pressure would be lower. In the orginal post it was implied the oil pressure increased after adding oil. If the extra oil covered the crack, the pump would not suck air and the oil pressure would return as if the crack did not exist.

Hobo,NC · Nov 18, 2015

When I can not read the dipstick because the oil is to clean I paint the tip with a sharpie :wink:

gary1466 · Nov 19, 2015

(quoted from post at 19:23:19 11/18/15)
When I can not read the dipstick because the oil is to clean I paint the tip with a sharpie :wink:

I would wonder if the pickup tube gasket used was the correct one. Gasket kits include a gasket that has a odd shape opening instead of the normal rectangle shape. it may be sucking air. Drive to a steep slope with the right side on the downside to see if this makes a difference. I know the tractors oil level is almost pan full. suction tube bolts to front cover not far above pan gasket surface this may cover air leak

Hobo,NC · Nov 19, 2015

(quoted from post at 02:01:20 11/20/15)

(quoted from post at 19:23:19 11/18/15)
When I can not read the dipstick because the oil is to clean I paint the tip with a sharpie :wink:

Click to expand...

I would wonder if the pickup tube gasket used was the correct one. Gasket kits include a gasket that has a odd shape opening instead of the normal rectangle shape. it may be sucking air. Drive to a steep slope with the right side on the downside to see if this makes a difference. I know the tractors oil level is almost pan full. suction tube bolts to front cover not far above pan gasket surface this may cover air leak

He needs to put a master test gauge on it and verify he has a issue. If he does he will need to do some test with the gauge installed before he cracks it open. Until he does that I would not venture a guess.

Depending on were the test gauge taps into the circuit could point in the direction he needs to go.

Interested in opinions about oil pressure

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