I have a 2018 cat 246d with 825 hours. I just noticed oil separation in the antifreeze reserve tank. I siphoned out approximately 5 oz of oil. I'm assuming engine oil? Could it be hydraulic oil? Any idea what's going on? tia!
The oil I siphoned off smells more like hydraulic oil than engine oil.
Shouldn't be hydraulic oil. I don't believe there is any spot on that machine where they could cross-contaminate. I think they might have an engine oil cooler around the oil filter base. Been a few years since I last touched a CAT skid steer. Post the last 8 of the S/N and I'm sure someone with SIS can help you out.
Byfo4657 There are no other signs or symptoms of any issues. No leaks no smoke no power loss
Don't usually see much for head gasket failures on those engines in my experience. If you do the main symptom is usually pushing coolant out of the rad and into the plastic bottle, as well as issues with cab heat.
The actual coolant level has stayed the same where it should be. The oil was on top of the antifreeze. I've started running the air conditioner and it is fine. I'll check the heat. How does the engine oil cooler fail and allow fluid transfers? Is it a gasket issue within the cooler or is it a crack somewhere? Seems like there would be some sort of a leak with a cooler failure
I'm not entirely sure it has an oil cooler, I can only go off memory as I no longer have access to SIS.
Absolutely. the hydraulic oil cooler is piggy-backed in a package with tbe coolant radiator and both are air-cooled. Not sure it has an oil cooler either. At least I can't see one from a quick glance.
I knew they were side by side but I could have sworn they were separate units. Guess my memory's a bit foggy there too.
This is what they Are showing for engine oil cooler
That's the one @92U 3406 was talking about. The engine oil cooler #3 is in the base of the engine oil filter. That's where engine oil under a fair amount of pressure is right next to coolant at maybe 10psi. On the OP's machine both radiator and the hyd cooler are just one Part Number.
Is it possible that the crossover of fluid is happening at the engine oil cooler?
Certainly. Try disconnecting the coolant pipes where circled and temporarily connect the two hoses together. Then start the engine and check if you have oil coming out of the circled coolant ports of the cooler.
Update* spoke with a cat mechanic and he said oil cooler failure was somewhat common on these and was pretty sure that's what I had going on. I went ahead and replaced the cooler (not a bad job) and flushed the radiator. Ran it for a few hrs with so sign of oil in the reservoir.
Did you flush the cooling system with detergent.? If not you might find traces of oil appearing in the expansion tank from time to time literally forever. The best thing to use is Cascade dishwasher detergent because it is non-foaming. Don’t be shy with it, toss a load in and get the cooling system well warm. Rinse and repeat until there is no trace of oil when the system is drained.
I have not flushed the system with detergent. I did remove all the oil from the reservoir tank prior to flushing. As of now I have no oil showing up in the reservoir tank after a few hours of running. If I do I will use the detergent method. Thanks!
*UPDATE* I've got a small amount of oil showing back up in my antifreeze reservoir. The oil cooler was replaced last year and the machine ran fine all year. There are no other symptoms going on with the machine. I guess it could be possible that residual oil from the initial oil cooler issue is still in the line but I don't believe this is the case considering it was ran all last year without incident. What are some other things to start looking for in this situation? I'm assuming it's not the actual oil cooler that is the issue. I recently changed the oil and filter. It was around this time that I noticed the oil. Not sure if this is anything to look into or just a coincidence. TIA Byfo4657
Myself I would drain only the reservoir, give it a good cleaning and refill it with fresh coolant. If you get a noticeable amount of oil back in there in a short period of time then I'd investigate it further.
If I clean out the reservoir and I am still getting oil back in where should I look next?