JD 450 D LC overheating

[Dellroy Duke]

John Deere 450D LC excavator overheating. Looking for a reason. Working on excavator for a friend after he has spent thousands on dealer mechanics. Scenario is, engine began overheating 3 months ago, dealer tech came out to yard, checked it over with heat gun and said sensor was reading wrong. My friend replaced sensor and added mechanical gauge still over heating. A different dealer mechanic came out and determined engine needed new thermostats. He R&R thermostats, still overheats. Another mechanic determined hydraulic fan clutch operating in reverse ( blowing out from engine compartment). Rebuilt fan clutch and control valve. My friend degreased and pressure washed radiator ( numerous times) until clean and light can be seen through. Ran machine and still overheating but not as quickly. After about 20 mins. of loading busted up concrete into crusher it over heats. I worked on it a few days ago and found exhaust “spark arrester” about half plugged on outlet. Opened up exhaust and ran. Will run all day at full rpm without overheating now but after about 40 mins. of operating hydraulics, engine gets to redline. Stop using the hydraulics and it cools down in about 2 mins. Again, no heavy digging, just loading busted up concrete into hopper. Radiator and hydraulic cooler are not stacked, they are side by side. 180 degree thermostats were installed but if you watch temp gauge while running you can see the temp. fluctuating. Tops out at about 220 and then drops to about 170 and starts the process all over. Good flow in radiator after thermostats open, looking through cap. Almost acts as if thermostats ( one or both ) are not opening until temp reaches 220 but they are new and doesn’t explain why only overheating while hydraulics in use. Any help would be appreciated. Read all the threads I could but nothing for this scenario that I found. Sorry so long winded and thanks in advance for any help.

 

[Dave Neubert]

did it overheat since he had it or did it just start doing it. never mind does the hydrulics seem to be loading the engine more than it used to

 

[Dellroy Duke]

did it overheat since he had it or did it just start doing it. never mind does the hydrulics seem to be loading the engine more than it used to

No on the hydraulics overloading. Responds as always, No added strain with any function of the hydraulics. Very noisy area with crusher and screen running, but couldn’t hear any hydraulic squeal from a bypass or blown relief valve. Got the machine overheated then let it cool to normal operating temp. and held the bucket and boom controls against the stops in all positions with no increase of engine temp.

 

[Delmer]

Just seeing light through the radiator doesn't make it clean, that's the minimum that it's not plugged completely! use the light and LOOK at the fins to see if it's clean. The fact that it cools down quickly suggests it could be still plugged on the air side.

Use a non contact thermometer to confirm thermostat temp, block temp, and radiator return temp at the water pump inlet, while it's as hot as you get it. That will help guess better.

Could be the fan is turning on and off at 170 and 200 to control the temperature. Might help to post a serial number, I don't do hydraulic fans, but that's the first thing they need to look it up.

 

[Dave Neubert]

Check the speed of the fan and like Delmer said check top and bottom of raidaitor to see the temp differance it could be partly plugged internaly

 

[Mike85]

Did you check temp differential between top and bottom radiator hoses? The rad could be internally clogged.

 

[Dellroy Duke]

Just seeing light through the radiator doesn't make it clean, that's the minimum that it's not plugged completely! use the light and LOOK at the fins to see if it's clean. The fact that it cools down quickly suggests it could be still plugged on the air side.

Use a non contact thermometer to confirm thermostat temp, block temp, and radiator return temp at the water pump inlet, while it's as hot as you get it. That will help guess better.

Could be the fan is turning on and off at 170 and 200 to control the temperature. Might help to post a serial number, I don't do hydraulic fans, but that's the first thing they need to look it up.

Thanks for the insight. I’ll check fan speed and get his SN.

 

[Dellroy Duke]

I could not check the differential on the last time it overheated because he had it parked on the top of the rubble pile. I’ll check with him today to see if it’s on the ground yet. Thanks.

 

[Dellroy Duke]

This manual contains high quality images, instructions to help you to troubleshoot, and repair your truck. This document is printable, without restrictions, contains searchable text, bookmarks, crosslinks for easy navigation.

John Deere 450DLC Excavator Service Repair Technical Manual

Thank you so much. One item he and I don’t have. Great help.

 

[BIGHOSSHARLEYRIDER]

Having same issue. What did you do to resolve it?