I am still puzzled by my recent cooling problems with my JD450C. I did a job last month and noticed it started running hot. I was able to rev the engine enough to cycle the thermostat and cool the engine back down. I noticed no leaks but added some K-Seal Radiator Repair. No change. I have the dozer back at the shop now. I have replaced the thermostat, radiator cap, tightened the belt which was little loose to the point I could turn slip the fan, I just flushed the system yesterday and thought I had solved the problem as I let it run for over an hour and monitored the temp. I also was changing out the water as I was flushing the system. I noticed that when I rev the engine between 1800-2200 rpms, the thermostat will open and cool the engine....sometimes it opens around 190....other times it will go up to 200 + before opening. I let it idle for a while and noticed it was opening and closing like normal....then I continued to let it run and checked on it and it had began to run hot again and it had overflowed....immediately pulled the cap off and added water again and it cooled down. At this point, I am running just water as I don't want to waste the anti-freeze until I figure out the problem. Could the water pump be going bad as there are times when the water exchange happens but other times it doesn't? I am at a lost for figuring it out now and I hate to go thru all the work to pull the nose off and labor until I can properly diagnose it.
It sounds like it could be a head gasket, if you fill up the cooling system and let it run with no radiator cap on it and see if it is making bubbles that’s usually a tell tale sign of a head gasket leaking. I have a Deere 350 dozer was having similar issues a few years back and ended up being a head gasket.
If its a head gasket putting gases into the system, drill a couple small holes in t-stat to let air out as a test if it is an automotive style t-stat.
Yikes! I do remember seeing bubbles and foam inside the radiator when I pulled the cap. Can I just pull the head without having to pull off the nose and front engine cover? Any tips on this repair if I have to pull the head?
After reading Andy81's post, I am seeing bubbles and foam in the radiator when I pull the cap. It is an automotive style t-stat Did you have any block cracks once you inspected?
Is it bubbling at Low Idle with the engine warm, or do you have to take it to High Idle before you see bubbles..?
Once I drill a couple of small holes, I'm guessing this post goes hand in hand with Andy81's post....the holes will allow the gases to pass into the radiator which will make it easier/quicker for me to see bubbles...am I correct? If I don't drill holes to let the gases by, will I still be able to see air bubbles making their way to the top of the radiator?
If the thermostat is even slightly open, which it ought to be with the engine warm, yes.
I haven't really checked ....other than I remember seeing foam when I pulled the cap; however, this could also be a result of the K-Seal radiator sealant that I poured in as well. I will remove the radiator cap and let the engine warm up to see if I see any bubbles surface. I may have created an air pocket as well as I was opening the drain cock on the block when changing out the coolant...flushing the engine.
The continuous stream of small-ish bubbles you will see resulting from combustion gases entering the cooling system will be completely different to the "burp" that happens when a pocket of air trapped in a cooling system is released.
Ok, thx....I will remove the cap and look to see bubbles. If this is the problem, do I need to pull the nose, radiator and the water pump to access complete removal of the head and checking valve clearance upon reassembly?
Pick up one of these. It takes the guess work out of knowing if you have a combustion leak in the cooling system.
Pardon my ignorance, but how do you use it and where can I find one?
I just looked it up and now I understand it. thx for suggestion.
I have found with this test kit it has to be a real bad leak on a diesel for it to work, fluid will typically go from blue to green i have only had one diesel actually turn it yellow , and didnt need the test kit to know what was going it was to show the customer.
It will make it quit heating up because the air cant get trapped by the t stat. And will probably help with the block check fluid if you try it as you dont want to suck up cooling water into the fluid
You have to get the right test fluid for it the one for diesel. Bob
I haven’t had much luck with the combustion gas test kits when used on diesels, either. I use the Caterpillar air displacement method. Modified radiator cap or fitting with a tube going to a inverted Nalgene bottle filled with water. Run the engine at temp for 1 minute and measure water displacement. Compare to spec based on engine size. That probably doesn’t make much sense. Cat has a Special Instruction published for this method. You can buy a kit with the vented cap, hose, instructions and container.
Check if there's water or coolant in the oil too.
I found the special instruction for the Cat Bottle Test. Air and gas in the system can also be checked by another simple test called the Bottle Test. The equipment needed to perform this test is a bucket of water, a calibrated half liter or pint bottle and a length of hose attached to a modified radiator cap. After the pressure test the engine should already be at operating temperature [90°C to 99°C (195°F to 210°F)] and the expansion air and gases vented. Install the modified radiator cap and hose. Submerge the bottle in the bucket, filling the bottle completely with water. Invert the bottle keeping the mouth under water. Place the loose end of the hose into the water-filled bottle. Continue to run the engine at constant temperature and rpm (between 1500 to 1800 rpm). If there is a combustion gas leak, the gases will make their way to the radiator, through the hose and into the inverted bottle. If more than 0.5 L (0.13 gal) of water per minute is displaced, air or gas entering the cooling system is excessive. Under a load condition on a dyno, 0.75 L (.195 gal) per minute would be excessive. There is probably an internal leak that will require removal and inspection of the cylinder head, gasket, injector adaptors or cylinder liners.
The Cat Bottle Test specs above are for a 10 liter engine. You can do the math and adjust it for different displacements. Or, I’ll try and find my chart from Truck Engine Analyst class way back in the day.
Haven't seen the chocolate milk, thank God.
The 450C back when I was working on them were known for head gasket problems. And from people over-torquing the head bolts going back together, cracked blocks. The cracks occur in the web wall below the deck, so you could only find them after pulling the liners. Learned that the hard way after changing a couple gaskets after the last mechanic had already changed it a couple times and then finally sending the block in to be decked. Hope you have better luck.
Thx much, I filled the radiator with water and cranked it up....didn't see any bubbles so I'm going to try changing the water pump. An old diesel mechanic told me that he has seen it where the water pump propellers sometimes just wear down and fail to move the water like it should. I'm hoping that is my problem....crossing my fingers.
have you checked inlet and outlet temps of the radiator? Cat has a psi spec to verify if the water pump is working correctly.
Nowing75, That’s a good point. I’ve seen many great Techs that struggle with trying to diagnose cooling system issues. Understanding the concept of heat rise across an engine block is a life-changing revelation. No engine manufacturer that I’m aware of, other than Cat, provides those specs. To locate them in the Cat system, look in the TMI. Go to test spec data and look for “ Delta T Jacket Water ( in-out). It will Be in the 12-14 degree range.
Simplified, check the radiator inlet and outlet temps with a infrared thermometer, while the engine is overheating. Thermostat should be open. Should see a Delta T around 12 degrees across the radiator. This is the fun part; if the Delta T is greater, it means a flow problem. The coolant is spending too much time in the radiator. ( bad water pump, internally plugged radiator) If the Delta T is less than 12 degrees, it means a capacity problem. ( externally plugged radiator, radiator inadequately speced, bad shroud, fan belt slipping, air flow issue. Summary: capacity issue or a flow issue.
Special shout out to the Caterpillar Technical Communicator & Engine Trainer at the Halton Company back in 1993 that taught me that concept during the week-long engine diagnosis class. He even put bugs in the cooling systems of a couple machines that we had to T/S overheat and overcooling conditions. Cat even provides test ports on their engines so temp probes can be installed to monitor JW in, JW out and water mix temps. Monitor all three temps and record at 2 minute intervals during the complete thermal cycle.
No, I had no idea about this process.
get a non contact thermometer, you can get a good one used off fleabay for $10-20, the only downside is they're not accurate on shiny bare metal, so I like to take the temperature of the painted inlet on the engine from the bottom radiator hose, and the outlet to the top of the radiator. Take these temps when the engine is as hot as you have run it, and as quick as you can safely can.
I had the same overheating problem with my 350 - radiator was just dirty with soot from a hole in the exhaust under the hood, and a little oil, over time just built up a small layer of grime on the radiator. I really didn't think it would be the problem but after doing the water pump and seeing no difference, pressure washing the radiator fixed my overheating problem. It doesn't cost a thing and is worth a try. I do it beginning of every year now and it definitely helps.