Oil too hot
 

What would cause my oil to get too hot? I didn't have the problem until I had my oil changed. Now when climbing out of California or on 80 out of Salt Lake my oil temp warning comes on. The ambient air temp is warmer now than before the oil was changed. I have an ISX 530 HP.

Where did you get your oil changed?

Ambient air temp will affect oil temp somewhat. So will the load on the engine and how much oil is in the pan.

Do you have an oil temp gauge?

If not how do you know its too hot?

It should be the same as the water temp or lower

I had the same issue with a 07 565 thermostat in the oil cooler I think.

Mine would derate at 250f

The oil temp on my ISX runs 230 all the time while my water temp runs 190.

I had a oil themostat stick closed and the oil temp rose and shut the engine down. Part was cheap but the labor at a Cummins shop was a little pricey. I think the total bill was around $700

The oil cooler is the first cooler on the front. What sort of shape is it in? Are a majority of the vanes bent closed?

The oil cooler on a ISX is below the exhaust manifold on the passenger side. My ISX has a double oil cooler.

When it got pinhole in it I replaced it for $2,000

How does the engine fan draw air thru it down there? Seems like a great spot for an oil heater!

I thought the same thing when they pointed out my oil cooler to me. It bolts to the block and has your coolant flowing through it and I don't think air has anything to do with cooling the oil on a ISX.

I had oil in my coolant so I took it to the shop and they said the oil cooler has a hole in it so I asked how big a job. They pointed to the cooler and said about everything on this side of the engine has to come off..

I thought what a dumb place to put something you are trying to cool.

The oil thermostat is in the front of the block behind the ac compressor.......I never figured that one out either.

Just goes to show why you would not want me turning wrenches on a truck!!

That's the trans oil cooler up in the front.

The engine oil coolers is actually water cooled, that's why I said the temp is usually close to what the water temp is, at least on my Cat it is.

There are no thermostats on the oil cooler that I know of, again that would be on a Cat

He said he had a ISX 530hp

Yes the ISX has an oil cooler thermostat which goes into the front of the oil cooler.
Here's a picture of it from the service manual.

The oil cooler uses the engine's cooling system to remove heat from the engine oil; that cooler is NEVER found out by the radiator, that I've ever heard of, always installed on the side of the engine block. It is normal for engine oil temp to run higher than engine coolant temp.

If oil temp is going out of range, and coolant temp is not; First thing to check is the oil level, and check oil for coolant contamination. Second, verify that the ECM is reading the oil temp correctly. If the oil is running too hot (and coolant is not), the oil thermostat could be the cause.

Keep in mind, engine oil degrades quickly in high temps.

The job of a thermostat (oil or coolant) is not simply to cool, it is to maintain temperature within a given range; too cold = bad, too hot = bad.

Oil Thermostats Replaced
 

So far I have replaced the oil temp sensor ($150) and the oil thermostats ($802 at cummins). My oil still overheats on long or severe pulls. Coming back from Ohio with 43500 lbs in the box, I got alarms on the long steady pull up to Laramie WY and on Donner Pass. Both times near the top so I have significant capacity to pull, just not enough.

I do have a very small amount of coolant in my oil, not enough to make cream, but I have to add about a quart of coolant every three to four days.

I am really afraid this is going to get very expensive.

How do you know that you have coolant in the oil?

Did you sample the oil and have it analyzed?

Just because you're adding a quart of coolant every 3 or 4 days doesn't mean the coolant is necessarily going into the oil.

If you do indeed have coolant in the oil (or vice versa), then have the oil cooler checked.

Since you've already tossed nearly a grand at it with no improvement, I'd recommend taking it back to the Cummins dealer and telling them you don't want to see it again until it's fixed right.

Starting to sound like my last truck... changed the oil cooler thermosats and ocasionaly it would still get a hot oil alarm and derate, it also used coolant but the oil samples must have been good still.

When I had the hole in the oil cooler I would get oil on the cap of the coolant tank and when you would poke a hole in the oil filter before taking it off a small amount of coolant would run out first.

Before changing the cooler my oil would heat up to right where the buzzer goes off on a long pull.

Now my oil temp never moves off 230 degrees.

The Cummins tech told me that the oil thermostats were 239 degrees so 230 is about right.

Oil was tested and showed chemicals consistent with coolant. When the oil changer poked holes in the oil filter some green fluid came out before the oil.

When I took it to Cummins they said troubleshooting the problem took several steps. I was fully aware that changing the thermostats may not fix the problem. I am not making much money at this yet so I am careful not to spend more than I have to. I guess I havent spent enough yet.

Sounds like a oil cooler is in your future.

Take your water filter off and see if it is full of oil. If your oil cooler has a hole in it your water filter will catch the oil.

Mine had a double oil cooler on it so it was a little more expensive to replace. I think it was around $2000-2300 to replace.

Ever since the first Cummins Turbo Charged 270HP, 855CI engines, the engine oil has been used to cool the pistons from the bottom. That's why oil temp is usually a little higher then the coolant temp. The pistons get very hot under a load so it would not be uncommon for the oil temp to get a little high when your pulling a long grade but the ECM should cut the power back before the oil temp light comes on.

Do you have a pyrometer (exhaust temp gauge) and have you noticed where its running when the oil temp light comes on?

If you are getting oil in the coolant and/or coolant in the oil, there are a few things that can cause that. The oil cooler has been mentioned and would be the most common failure. A pressure test by Cummins should help find the problem without all of the guess work.

So we all went the same place. Since my indication was oil overtemp we all fixated on oil. The problem was, are you ready?

Water temp sensor reading too low!

To exacerbate the problem my fan clutch hub was bad and I had a small hole in my heater core bleeding off pressure.

At any rate, I took it to Volvo in Albuquerque and said, fix it. I ask him how it was possible to boil coolant at 170 degrees. We replaced all the broken stuff and tested it. Still funky readings. Changed the temp sensor and everything fell in. Water temp was reading 130 to 150. Changed the sensor and water temp jumped up to 180 to 200.

Climes the hill on i40 and the oil never budged above 231.

Thanks for the update LostSoul.

So it would seem that the temp sensor was the key component here. It was not reporting the correct temp to the computer so the engine was not cutting back as the temp climbed. The only indication was in the oil temp. I hadn't heard that the coolant was boiling.

I wonder if the fan hub was really bad or just not coming on because of the incorrect coolant temp reading.

Were you having any issue with fog on the inside of the windows from the leak in the heater core?

Shnerdly, you hadn't heard that the water was boiling because I forgot to mention it. That was the missing piece. While stuck on the side of the road near flagstaff waiting for her to cool it hit me...water doesn't boil at 170 degrees and if the temp sensor was defective and the coolant was much hotter than what was being reported all of our current symtoms would occur. And of course with the heater core leaking blessing off pressure it made it even worse.

Actually it wasn't the fan clutch but the hub that was bad.

Hi,

for charge air cooler queries of problems you should contact Vestas aircoil, they manufacture and design charge air coolers for large diesel engines. Not so much for trucks though, but should be able to give any advise regarding cooling.

Hi,

Reading through the posts here on charge air coolers, if you have any questions I may be able to assist. I work for a company called Vestas aircoil who design and manufacture charge air coolers for diesel engines.