Hi, We have a Deere 6068HF engine running an irrigation pump. I figured it might be the most similar to the generator area as both are industrial engines. Serial number is PE6068L249542 and it has roughly 3000 hrs on it. We keep getting a fault pop up on the screen that reads “Engine Coolant Temp Signal Slightly High” with SPN 110 and FMI 15 above it on the screen. Coolant temp was 205 on the screen. Checked the obvious things like coolant and radiator, and they seem clean and new coolant this season. This fault has popped up from time to time before and don’t want to be stuck without a pump this time of year. Not sure if there’s any troubleshooting that can be done in the field or through the screen, maybe to determine if the sensor might be the culprit, but any help appreciated. Thank you.
Not much you can do with that monitor. Belt good? First thing I would do is compare the temperature you read with the monitor with the temperature taken at the thermostat housing (that is where the temp sender is mounted) with an infrared temp gun. See if they match (+/- a few degrees). Post results. Also shoot the upper radiator hose and the lower radiator hose (engine running and code active) or top radiator tank and bottom radiator tank and note the temperature difference. Post results.
Ok so pump was running all day today and screen was reading 205 again. Fault wasn’t up, but I took the temps to get an idea. Temp sender 199-202 Upper hose 170/ inlet at block 201 Lower hose 145/ inlet at block 190 Upper radiator 147 Lower radiator 170 Front cover 200 The belt also seemed to have good tension and looked in decent shape
Close enough. I don't suspect a sensor issue. I know many here on the forum would say your temperature drop would be perfect. But Deere likes to keep a tight temperature drop (on their own equipment at least). Approximately 10*F although I would be comfortable with up 15* difference. Your temps indicate a 23-25* difference. So I would suspect a coolant flow issue because the coolant is sitting in the radiator too long causing the higher temperature drop. A thermostat that won't open all the way could cause that. Also a water pump could cause that as well. If I recall correctly, those engines have a plastic impeller. If one or more of the fins broke, or the impeller starts to slip on the pump shaft that could give those issues. With the above being said, when a Deere engine is put into an OEM application, many times the OEM supplier puts the cooling system in and not Deere. So those temperature drops could vary and can be like throwing darts to determine what is normal, even though Deere supplies them with cooling system capacity requirements. Seem clean and being clean are two different things. If possible try to wash out the radiator fins to be sure it is clean. Also make sure any baffles around the radiator are in place and not allowing air recirculation. I have seen normal temperature drops on cooling systems and still have overheat issues that ended up being air recirculation issues.
Some of those engines had plastic implers in the water pump it maybe stating to slip on the shaft
Cheap trouble shooting pull the water pump and check the impeller. Bob
Thanks for the suggestions everyone. I’m going to wash out the radiator first, and then on to checking the water pump/thermostat if that doesn’t help. Not sure if it matters, but it doesn’t get run under a hard load, the screen shows about a 40% load when running at 1500 rpm, but can run for almost 24 hours depending on the weather. Thanks again
Running at 40% load is not ideal for prolonged operation in a compression ignition engine, especially in a standalone application with a governed rpm. I'm sure there are many different opinions out there but personally I like to see a diesel primary mover pulling between 75 - 90% load. Prolonged operation (especially in colder weather) in an under load condition will lead to wet stacking (incomplete combustion, carbon/sludge buildup) which will certainly decrease the service life of your engine. In my experience those 6068's are a very reliable platform, run em hard and give them the love and maintenance they need and they will serve you a long time indeed. As a bonus they are a dead simple engine to overhaul, and the parts are cheap and available. Love em!