Now that it's pushing 100 I've been battling cooling issues with my 322C BKJ with a 3126. In past years it has stayed cool in high ambient conditions. I've washed the radiator several times and am fairly certain it's clean. No improvement. This morning I changed the thermostat and tightened the water pump belt. The fan belts are in good condition. No improvement. So I'm back to grasping at straws. I'm curious if there is a way to check water flow. I shot the radiator with a heat gun. The top was 195 and the bottom was 155. I don't know what it should be but this seems like a good temperature differential. I wonder if perhaps the water pump isn't moving enough water, but I would like to know before I swap it.
A temp drop of 10 to 15 deg would be lots. The 40 deg drop indicates an internally clogged rad core to me. How ever the water pump has it's own belt that rarely gets tightened. Check it's adjustment first. Later Bob
I just had that same issue with a 325B..... and I was sure the radiator was clean.... washed it many times and it still heated... finally had to go under the hood,,, turn the fan little by little and cleaned it thru the finger screens.... now she cools.
The water pump belt is tight. The radiator is clean externally. I am 100% positive. The machine cooled fine last summer and earlier this summer. It has the cat red coolant in it. I can't imagine why it would be internally clogged all of the sudden. Could the 40 degree drop be caused by lack of water flow, i.e. Bad water pump. I just haven't heard of a water pump failing in that way. I've had the impeller come loose from the shaft in a cummins before, but that was an immediate total failure, you couldn't operate the machine at all without overheating very quickly. I could pull the bottom radiator hose and pour water in the top to check flow. I had the cap off the other day with the engine running. Wouldn't it have overflowed if the core was plugged internally and water pump was pumping fine.
Did you see coolant circulating when you had cap off?
No, not unless you had a separate tank on the suction side of the water pump. The water pump can't push out any more water than it pulls in. 195 is not that hot, can you shoot some readings on the engine to confirm it's hotter than it should be? I'd be the first one to call you a liar for claiming the radiator is clean on the outside, but the big temp drop says that's not the problem. That leaves the pump, belt, crank pulley (one of the last stumpers had a loose crank pulley) Those temperatures were from when the engine was running hot, right?
I don't know why you would call me a liar. Maybe I'll call you fat. If it had to be any cleaner they have design issues. You could see water churning in the tank, but I couldn't get any idea as to flow volume. I shot the temperature on the thermostat housing at 210, at that time the gauge wasn't very close to the red maybe 2 bars down. One thing that makes me think there is a water flow issue is that after the machine heats up close to red, I'll stop to let it idle. In about 45 seconds it will drop one bar on the gauge and in another 45 seconds it will drop 2 more bars. Which seems really fast to me. I don't know what the actual temperature drop is as I didn't have the temperature gun with me at the time. I'm going to have a hard time shutting it down to swap parts next week, but if I was reasonably sure of a fix I would. If it doesn't get worse I can baby it along and finish the project. I would put a water pump on tomorrow if I had one on hand. Is there a way to verify adequate coolant circulation?
We shot those temperatures in a hurry so as not to stop work. I'll go exercise it tomorrow and get some more readings.
If the core is clogged internally the coolant level in the top tank should drop at full speed and rise at low speed with thermostat open. Get someone to change the speeds as you watch with the cap off the rad. If you have a variable speed fan it could be causing trouble. Later Bob
Statistics/experience. When people say they've washed/cleaned a radiator and it's still overheating, it's usually still plugged even though it looks clean from the outside. You have to get up close and have some light on the other side to see the build up between the tubes and fins. BUT that's not what I would expect the temps you posted, unless those temps are much different when it's overheating, say 210 and 200. I'll have to change my name now, I kinda like Fat Delmer.
I know what you were getting at. I've sent guys to wash a radiator before and they come back 5 minutes later and say it's done. Not the case here.
We have put clear hose in place of heater hose, run it up to open hood and watch for circulation. How's the air filter, is the foam missing from inside the hood to seal off hood and radiator top, other wise hot air will be pulled around instead of exiting out side.
Thanks for mentioning the piece of foam overworked. I went out to the machine today, it is missing. I wouldn't have thought of it causing a problem. I jerry- rigged a piece of pipe insulation in its place. I worked it hard for an hour or so this afternoon, and no cooling problems. Tomorrow will be the real test. I also drained the coolant and flushed the radiator. While I was at that I pulled the bottom radiator hose and dumped water in the top. It would drain through the radiator faster than I could pour it in. I guess that means its not plugged internally. I didn't attempt to check the flow from the water pump, because I will just replace it if I have cooling problems tomorrow. Thanks for all your responses. If someone knows better, please let me know if my method for testing flow through the radiator actually confirms it's functionality.
I think if it's falling out of the bottom faster than you can put it in the top you don't have a problem with internal plugging of the radiator core. Another thing to look for. Do you have any exhaust leaks of the system under the hood..? That could significantly increase the temperature of the engine compartment and reduce cooling efficiency. The Rule of Thumb for a conventional core radiator like this one is that a difference of about 12-15 DegF between the temperatures of the top hose and bottom hose indicates the radiator is cooling correctly.
I think my heat gun doesn't like sitting in a hot pickup seat. It was giving me crazy readings yesterday. However the machine ran 11 hours today in horrible hot dusty conditions and the temperature stayed well within normal operating range. I guess that little piece of foam over the radiator was put there for a reason, go figure. I had a raccoon take up residence in the machine over a weekend back in June, and made a nest of most of the foam on the doors in the hydraulic pump compartment. Perhaps he got that piece too. I hope the other pieces weren't as important. Thanks for all the help. I wouldn't have figured that out if not for this forum.