My John Deere 4720 is running hot in 15 minutes. Chronological history below. 1. Oil cooler leaked oil into radiator. I had to flush the cooling system and change the oil cooler twice so far. Still running hot. 2. Removed then changed then removed the thermostat again. Still running hot. 3. Changed the radiator thinking it plugged and flushing wasn’t clearing it. Still running hot. 4. I did a pressure test to 14psi and vacuum test with full vacuum while engine was warm. It held both pressure and vacuum. Still running hot. 5. I tested for a head gasket leak with the leak detector liquid 3 times. I didn’t detect a leak. I didn’t see any bubbles before checking but I wanted to rule it out. Still running hot. 6. Disconnected the discharge of the water pump where it goes into the top of the radiator and extended the radiator hose so it couldn’t gravity flow. I put a water hose in the radiator to keep a water supply to the water pump and ran it to test how well the water pump was pumping. It pumped good but had instances where it would burp bubbles. (I have a video of this) I raised the water pump hose about 4’ to give it some head pressure to pump against and it still pumped good. Still running hot. 7. I elevated the front of the tractor and ran it to see if maybe it had an air lock in the engine and wasn’t getting completely full of water. Still running hot. 8. I couldn’t think of anything else to do so I removed the head. I didn’t see any cracks on the head gasket, the head or the block. 9. I looked at the water passages in the head and block and they are clear. I flushed the head with a water hose through all of the ports and water flowed well. 10. I noticed that the tractor was hard to push by hand when in neutral. I found the linkage from the emergency brake was bent and slightly activating the brakes. I don’t think that was enough to make it run hot, but I wanted to mention it. 11. Another thing that I noticed was that it looks like the water pump impeller ate into the plate that it attaches too. The wear is only about a 1/16” but I was wondering if that’s enough to let discharge pressure flow straight to the suction side and limit how much flows through the head. I think I ruled this out as a problem by testing the water pump flow with the discharge hose disconnected. I just wanted to mention it. ( I have pictures of this also). Sooo, I’m not sure what to do next. I still have to put the head back on. But I’m scared that wasn’t the problem?
Deere 4024 engine in that, correct? What temperature are you running? Did you test the accuracy of the temperature gauge? Post a picture of the wear on the timing cover from the water pump. That only happens when there has been either an impeller failure or a bearing failure in the water pump. Has the water pump had a previous failure and was replaced? You mentioned you replaced the oil cooler twice for oil contamination. Are you still getting oil contamination, or has that been resolved?
Thanks for your questions. 1. I’m not sure what engine it is but I attached the number plate below. 2. The original thermostat didn’t have any numbers stamped on it and the new one that I bought didn’t have any on it also. I researched online and it said 180° thermostat. So I assume that the temperature the engine should run. 3. I checked the water temp and around the engine with a laser temp gun. The water temp was about 220° with a 180° thermostat. The engine block was hotter in the rear by about 10°. I checked the oil temperature before the oil cooler and it was about 230° and after the oil cooler was about 220°. Seems high. but interestingly enough right before I brought it into my shop to take the head off my temperature gauge quit working and was stuck all the to right indicating very hot as soon as I turn the key but without the engine running. So I thought that my sensor was bad and I changed the sensor. The gauge still pegged out after I changed the sensor so I assumed it was the gauge. The gauge is part of the instrument cluster and doesn’t look like it can be changed without changing the cluster. I would be mad if it was the gauge the whole time but would be relieved to know finally know what’s wrong. I believe the cluster went out due to heat from the engine. The plastic started changing color like it got hot. I wanted to test the temp sensor in a cup of water and heat it with a torch but now the gauge quit working so it wouldn’t be representative test now. 4. I attached a picture of the timing cover wear below. 5. The oil contamination problem was solved after the second cooler replacement.
This is a link to a YouTube video of my water pump test.
4024?!?! Call that abomination a “Powertech” was a blasfeme !
I really like the tractor and haven’t had any problems with it. I brag on it often because it’s given me less problems than some of my other equipment.
Well - apparently you do have a problem, otherwise you wouldn’t be here.
That is strange and inconsistent bubbling out. Have you purge the air out of the cooling system?
With all my toiling on those pieces of crap on Atlas Copco - I’ve never had cooling problems with them ( on engine side). Mostly low boost and fuel system troubles.
I’m not sure how to purge the air out. I couldn’t find any high point that I could open. I did drive up my trailer ramps with the front tires and pick up the front even higher with the bucket to get the front of the tractor/radiator much higher than the engine so that it would let air out of the block. But that all I could think of.
The most effective way to ensure no air in the cooling system is by using a vacuum cooling system filler. Airlift, snapon, harbor freight probably sells them also. Eliminates any chance of an air pocket in the cooling system. Not insinuating this is your issue but it answers the question of air in the system.
Thanks, I’ll pull a vacuum on it when I fill it up.
Belt slipping? Seeing the timing cover wear, are you sure the bearings are good in that water pump? Impeller tight on the shaft?
Is the tractor low on power? Blowing smoke? Blue, white or black? Will it over heat at idle/ high idle or only when operating?
I checked both pumps.(the one that was on it when I bought it add the new one I installed when it started running hot). Both pumps didn’t have any slack in the bearings and I didn’t see any damage to the impellers. That leads me to believe that the damage must have came from a water pump that got changed by the previous owner. I bought it about 15 years ago. So that would mean that it ran for 15 years with that damage done to the timing cover and it didn’t run hot. At least that’s what I’m thinking right now. I attached pictures of the water pumps below. The on the left is the one that was on it when I bought it and the one on the right is the new one that I pump on. I can see what I think are the original stamp/press marks on the impeller from the manufacturing process. If the impellers were hitting the back plate, I thought I would see damage or scratches to the impellers.
It ran perfectly. Good power, no smoke. It didn’t run hot at idle.
This is my question. Is there any evidence the engine is running hot besides the gauge? You need to check the temps at the engine outlet and the engine inlet. If the thermostat is working correctly, it should open and allow and maintain the temp rating. The temp from the top of the radiator to the bottom will be 20-30 degrees on average depending on the fan speed and blade size.
I’m trying to follow the flow of water through the head and block when the thermostat is closed and I don’t see a port that allows the water to circulate from the discharge side of the pump then through the engine and back to the suction side of the pump. I always thought that when the thermostat is closed, the water will still circulate through the engine. But when the engine gets hot the thermostat will open then it will allow the water pump to pump through the engine then out to the radiator then back to the pump.
Is there a fan clutch? Is it engaging
It doesn’t have a fan clutch. The belt wasn’t slipping and it was turning the right direction.
Is the fan installed the right direction? We had a skid steer once, Deere, not that it matters, but the fan was flipped around. It still moved air, but only about half as much as it should. The fan blades should be moving like your hand cupping air.
Good question. Yes. It is pulling air through the radiator from front to back. I did route the belt in the wrong direction once and the fan was going backwards. But I corrected it.
If you can route it wrong to spin the fan backwards, is it possible to spin the water pump backwards?
Another good question. I did check, both belt routes and they both spun the water pump the right direction.
Is the pump driven with the flat side of the belt, or the grooved side? Sounds like there could be a couple different routing possibilities if you had a longer/shorter belt? I'm sorry if this sounds dumb, but when the water pump was off, I'd have taken a paint marker and put an arrow on the pulley showing direction.
It’s driven by the flat side.
I figured out the water flow. It does circulate through the engine and back to the suction side of the pump when the thermostat is closed. They have a journal molded into the timing cover that routes water back to the suction side of the pump.