Heavy Equipment Forums Heavy Equipment Community

06 JD 450 excavator overheating. Isuzu motor

daewoo 220lc-iii · 2025-06-15 14:04

Hello I have a 2006 JD 450 LC excavator. Starting to overheat, went to drain coolant and change thermostats. Couldnt find thermostats had to call mechanic. He can’t find them either. Go to drain coolant and rads full to the top. But get less than 5 gallons out of the drain. Thought inside of radiator might be plugged, put air to it and air comes out the drain, poured coolant back in and comes normal speed out the drain like there isn’t any internal restriction. Shouldn’t there be more than 5 gallons in the rad? It’s about 4x4ft and around 6-10 inches wide. Can’t find the thermostats (quoted 400$ each x2 for new), can’t seem to drain the coolant amount that should be in the rad, am I missing something?

Replies15
  1. #1daewoo 220lc-iii2025-06-15 14:09

    Ran fine at idle. Within 15 minutes of light work I checked fuel level and noticed temp was touching the red zone, dropped bucket and sat for 2 minutes and temp slowly started dropping. Shut machine down, hosed out rads, blew dust out of filters, checked coolant, everything looked good. Fired back up. Idled for 15 minutes till engine warmed up, temp was normal, once again 12 buckets of light work and back to red zone

  2. #2SLK0012025-06-15 14:13

    How many gallons does the manual say should be in the entire system. My 290G LC only holds 6 gallons in the entire system.

  3. #3SLK0012025-06-15 14:15

    Check for a collapsing return (suction) hose. Also, FIND the thermostats - they could be frozen, or clogged.

  4. #4daewoo 220lc-iii2025-06-15 18:38

    Says there should be around 55L or so for the cooling system. When we pulled the plug didn’t even get 20L even though it was full to the top, could most of the fluid be trapped in the block and egr. Or should it almost drain the whole system out the rad drain? Can’t seem to find the thermostats. Every diagram I find online, doesnt seem to match up to what I got even though everything’s stock. Some show a cover for thermostats similar to a car (2 bolts and bowl over it and hose fitting) some show a water manifold tube, my machine doesn’t seem to have either of them, I’ve included the 2 I found online to this reply but motor doesn’t have that manifold or the little thermostat cover

  5. #5Diesel Dave2025-06-16 11:13

    Thermostat location info and part #. See 2 screenshots below. ​

  6. #6daewoo 220lc-iii2025-06-16 11:24

    Awesome thank you very much Dave, it is greatly appreciated, I’m gonna head over and pull them out. Hopefully their the same ones I ordered lol

  7. #7Diesel Dave2025-06-16 11:36

    Thermostats part # 8983192540

  8. #8daewoo 220lc-iii2025-07-29 10:45

    Changed thermostats water pump cleaned radiator, new air filter same issue. Lasts about 20 minutes then almost touching red zone. Let cool for 4 minutes and back at 50% in the cool zone. Get 4 or 5 buckets in and back to red. Tried using heat gun on engine parts and cooling system everything reads nearly same temp. Can’t find any cooler or hotter locations. Engine runs fine no hesitation just slowly heats up. Over 6k into it and still same issue

  9. #9mg23612025-07-29 12:12

    What is the temperature you are seeing when it reaches the red zone with the heat gun? Is the hydraulic overheat light on? Hydraulically driven fan? If so, has the maximum fan speed been checked?

  10. #10daewoo 220lc-iii2025-07-29 18:04

    Photos of temps taken when coolant temp needle is 50% in the cool/blue zone, and again when it’s half a bar from touching the red zone. Averages 93*C and 110*C

  11. #11mg23612025-07-30 05:02

    Did you confirm those temperatures with an infrared temp gun at the thermostat housing

  12. #12SLK0012025-07-31 14:15

    Four minutes isn't near enough to cool back to the normal zone. I now suspect your temp sending unit. Performing mg2361's test of temp at the thermostat housing should confirm a bad sending unit.

  13. #13daewoo 220lc-iii2025-08-13 10:24

    Their temperature reads exact same as temp gun I bought. Sensors are reading accurately. Oil and coolant reach 110*C, takes approx 4 minutes for it to return to 83*C. New rad, new water pump, new thermostats, new sensors, new coolant, new engine oil, every filter on the machine new, new hyd oil….

  14. #14daewoo 220lc-iii2025-08-13 10:24

    Yup. Sensors read accurately. Both engine oil and coolant reaches 110*C

  15. #15mg23612025-08-13 12:20

    Has anyone checked the fan speed and compared it to specifications? That is checked with the hyd oil at 50-60*C, fan speed control solenoid unplugged, engine at fast idle, work mode set to dig mode and power mode set to HP. Fan speed should be 1270-1370 rpm.