Over heating engine

I have a PC180 LC-3 Komatsu trachoe that over heats after running for a couple hours, the low oil pressure light comes on then also(only when it gets too hot). It cools down faster if I leave the engine running fast vs putting at idle and the low oil pressure light goes off once it cools a little. I can leave the engine compartment hood open and it does not over heat. I had the water radiator cleaned, put new antifreeze and water into that goes down to about -20' when tested. I have replaced airfilters, the water flow from the water pump is strong at the hose going to the heater core in the cab. Put on new fan/water pump belts already.
There is some engine oil that comes out a crank case vent on the back side of the engine where the hydraulic oil pump mounts to the engine. The engine does not use oil or smoke. I never lose radiator water or have oil in the water or water in the oil. The engine has 10,000 hrs on it, I don't know if had been rebuilt in the past, I purchase it around with 9,400 hrs.

My question is could this be a weak oil pump? If so are any of you familiar with these and is the engine oil pump inside the oil pan, I believe this is a S6D95 model Komatsu engine?
Or what else could it be?

Thanks, Jason

it is standard procedure to run the engine at a fast idle like 1500-2000 rpm when cooling them down.it appears like a rad problem , either plugged cores inside or junk on the outside. when you say "cleaned" does that mean removed and boiled out in a red shop? and as for oil pressure could be due to engine brg. wear including oil pump. presume you have 15-40 oil in it. ideally u want to check the oil pressure with a master gauge when cold then as it working watch your pressure and if it drops the hotter the engine gets the engine is worn. once the engine gets to operating temp the oil is thinner and with greater brg. clearances the easier the oil escapes past the brgs. the oil pump then cant keep the pressure up.

Running it hot enough to thin the oil enough to have the oil light come on is an indication the the oil pressure is not much to begin with. Put a gauge on it. Second is oil type Using Delo, or Rotella, or Brand name 15-40 is a must (opinion). There may be a design problem getting air out of the engine compartment. Talk to a dealer about Service Bulletins. Having louvers or 12" holes made in the panels with electric temp controlled fans would likely fix it. Being tired (hours) is also a reason that it needs to work harder to do what you expect. If it is easy to start, then that is not likely. It could also have a hose collapsed internally that acts like a heart valve across the flow. Using a hand held infrared thermometer to assess the system can show where blockage is located. Jim

Sounds like an air flow problem, if it does not overheat with the hood open. With the hood closed, is it blocking air flow thru the radiator? Rev the engine up and hold a rag in front of the radiator-the fan should suck right up to the front of the radiator/grill. Or does your hood completely enclose the engine and restrict exit air, or are the radiator fins clogged with dirt? Mark.

(quoted from post at 12:58:58 12/31/20) Sounds like an air flow problem, if it does not overheat with the hood open. With the hood closed, is it blocking air flow thru the radiator? Rev the engine up and hold a rag in front of the radiator-the fan should suck right up to the front of the radiator/grill. Or does your hood completely enclose the engine and restrict exit air, or are the radiator fins clogged with dirt? Mark.

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Our big Mitsubitch, similar hours does the same, we take the motor enclosure (hood) off for the summer, end of problem.

Jim

Have seen this problem several times . So here are things to check , (1) make sure your fins are not plugged with dirt and dust or any oil spray ,(2) make sure your oil cooler fins are clean since the usually set in ft. of the rad. (3) have your Hyd. oil temp checked to make sure it is not getting hotter then Normal , if your dragging extra hot air thru the oil cooler then this will raise the Coolant temps . With age and the new antifreeze additives the tubes inside the rad built up a like ceramic coating and will NOT transfer the heat well . I had this happen on a semi . To solve that problem with out replacing the rad we got a system cleaner from Cat and to use you had to remove the T stats drain and flush the system ALL the way thru then ya added this one bottle and run the engine with the rad covered to bring engine temp up to 200 degrees and hold that temp for a half hour to 45 min. then drain and flush several times and install the Stats and refill with new antifreeze . When i did the semi you could not believe what all came out when i drained it . But the over heating problem was gone .

Yes the radiator shop boiled the radiator clean.
Fan blades are clean.
Yes I run Rotella 15-40 for diesels.
I am not a mechanic, where would I attach a manual oil pressure gauge to monitor pressures as it goes from cold to hot?
It does not have a oil pressure gauge or new enough to have a digital read out dash, I forgot to mention that.
It seems like to me this over heating issue began after I changed the oil about 2 oil changes back.

Thank for the inputs guys.

I'm wondering if all the problems might be in the instruments.

If it never boils over, never looses coolant, is it really overheating?

I would check it with a mechanical temp gauge with the sensor screwed into the head where the factory gauge is.

If it is overheating, and nothing has been changed about the sheet metal, or the fan shroud, it's possible the radiator is still clogged internally. May be time for a new core instead of having that one cleaned again. Radiator shops are afraid to get too aggressive with cleaning, start a leak, they get blamed.

As for the oil pressure, do put a mechanical gauge on it. Oil pressure light sensors are known to fail internally, give false low readings, especially if there is oil leaking from the sensor.

Mark might have it right. Make sure that you are not missing a bit of foam or other type of gasket around shroud. Had this happen on a crawler, did about everything but missed this simple thing.

Is it actually overheating, i.e. have you verified with a laser temp gun? Same with oil pressure, on many of my machines I have a small oil pressure gauge teed in where the idiot light switch is. I had a doosan excavator chase an overheating problem for a while, never boiled over but got very hot, new water pump and bigger thermostat housing was the update they offered, same problem, then I finally checked actual temperature with temp gun and found I had a bad temp sender, new sender and it's been fine.

Steve and Markct or whoever: what would be a normal operating temperature? I would guess 180' as idea temperature, based on my diesel vehicles usually running that and never any hot.
Those are good thoughts that I haven't checked, especially the sensor. I might have checked the temperature once, do not recall as that was likely 2 yrs ago.
Any reason to think the NAPA filter's are too restrictive and I should use Komatsu(dealer is 1 hour drive from me so I buy from local NAPA)?

Jason